|Masayuki Sasaki||Last modified date：2021.07.30|
Professor / Graduate School of Medical Sciences, Faculty of Medicine, Department of Health Sciences, Medical Quantum Science / Department of Health Sciences / Faculty of Medical Sciences
|Masayuki Sasaki||Last modified date：2021.07.30|
|1.||Yuma Tsubaki, Go Akamatsu, Natsumi Shimokawa, Suguru Katsube, Aya Takashima, Masayuki Sasaki, Development and evaluation of an automated quantification tool for amyloid PET images, EJNMMI Physics, 10.1186/s40658-020-00329-4, 7, 1, 2020.12, <title>Abstract</title>
Quantitative evaluation of amyloid positron emission tomography (PET) with standardized uptake value ratio (SUVR) plays a key role in clinical studies of Alzheimer’s disease (AD). We have proposed a PET-only (MR-free) amyloid quantification method, although some commercial software packages are required. The aim of this study was to develop an automated quantification tool for amyloid PET without using commercial software.
The quantification tool was created by combining four components: (1) anatomical standardization to positive and negative templates using NEUROSTAT <italic>stereo.exe</italic>; (2) similarity calculation between standardized images and respective templates based on normalized cross-correlation (selection of the image for SUVR measurement); (3) voxel value normalization by the mean value of reference regions (making an SUVR-scaled image); and (4) SUVR calculation based on pre-defined regions of interest (ROIs). We examined 166 subjects who underwent a [<sup>11</sup>C] Pittsburgh compound-B PET scan through the Japanese Alzheimer’s Disease Neuroimaging Initiative (J-ADNI) study. SUVRs in five ROIs (frontal lobe, temporal lobe, parietal lobe, occipital lobe, and posterior cingulate cortex and precuneus) were calculated with the cerebellar cortex as the reference region. The SUVRs obtained by our tool were compared with manual step-by-step processing and the conventional PMOD-based method (PMOD Technologies, Switzerland).
Compared with manual step-by-step processing, our developed automated quantification tool reduced processing time by 85%. The SUVRs obtained by the developed quantification tool were consistent with those obtained by manual processing. Compared with the conventional PMOD-based method, the developed quantification tool provided 1.5% lower SUVR values, on average. We determined that this bias is likely due to the difference in anatomical standardization methods.
We developed an automated quantification tool for amyloid PET images. Using this tool, SUVR values can be quickly measured without individual MRI and without commercial software. This quantification tool may be useful for clinical studies of AD.
|2.||Tetsu Nakaichi, Shozo Yamashita, Wataru Kawakami, Haruki Yamamoto, Masayuki Sasaki, Kunihiko Yokoyama, Accuracy of metabolic volume and total glycolysis among six threshold-based target segmentation algorithms, Annals of Nuclear Medicine, 10.1007/s12149-020-01484-5, 34, 8, 583-594, 2020.08.|
|3.||Natsumi Shimokawa, Go Akamatsu, Miyako Kadosaki, Masayuki Sasaki, Feasibility study of a PET-only amyloid quantification method: a comparison with visual interpretation., Annals of nuclear medicine, 10.1007/s12149-020-01486-3, 2020.06, OBJECTIVE: Visual evaluation is the standard for amyloid positron emission tomography (PET) examination, though the result depends upon the physician's subjective review of the images. Therefore, it is expected that objective quantitative evaluation is useful for image interpretation. In this study, we examined the usefulness of the quantitative evaluation of amyloid PET using a PET-only quantification method in comparison with visual evaluation. METHODS: In this study we retrospectively investigated a total of 166 individuals, including 58 cognitively normal controls, 62 individuals with mild cognitive impairment, and 46 individuals with early Alzheimer's disease. They underwent 11C-Pittsburgh compound-B (PiB) PET examination through the Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI). Amyloid accumulation in cerebral cortices was assessed using visual and quantitative methods. The quantitative evaluation was performed using the adaptive template method and empirically PiB-prone region of interest, and the standardized uptake value ratio (SUVR) in each area was obtained. RESULTS: Visual evaluation and SUVR were significantly correlated in the cerebral cortices (ρ = 0.85-0.87; p < 0.05). In visual evaluation, sensitivity, specificity, and accuracy were 78%, 76%, and 77%, respectively. Meanwhile, for quantitative evaluation, sensitivity, specificity, and accuracy were 77%, 79%, and 78% in mean cortical SUVR (mcSUVR) and 79%, 79%, and 79% in maximum SUVR (maxSUVR), respectively. CONCLUSION: The PET-only quantification method provided a concordant result with visual evaluation and was considered useful for amyloid PET..|
|4.||Akihiko Takahashi, Akihiko Takahashi, Kazuhiko Himuro, Keita Funada, Masayuki Sasaki, Shingo Baba, Impact of Collimator on DaT-SPECT Imaging: Monte Carlo Simulation Study, Radiology and Medical Diagnostic Imaging, 10.31487/j.rdi.2019.04.06, 1-6, 21 January, 2020., 2020.01, Aim: The purpose of this study was to assess the impact of the collimator in viewing the dopamine
transporter, using 123I ioflupane single-photon emission computed tomography (DaT-SPECT) images
utilizing a Monte Carlo simulation.
Methods: For the purpose of this study, the Monte Carlo simulation of electrons and photons (MCEP)-
SPECT was used. A numerical phantom was created from a real basal ganglia phantom and installed within
the code. The specific binding ratios (SBRs) were 5.03 and 2.01 for the background concentration of 7.44
kBq/mL or 7.04 and 3.03 for a background concentration of 5.56 kBq/mL. The simulated images were
evaluated using a recovery coefficient (RC). Initially, we simulated the performance of 14 collimators
without resolution correction to investigate the impact of the collimator dimension. The effects of two
resolution correction methods (collimator broad correction (CBC) and three-dimensional frequency–
distance relationship (3D-FDR)) on two reconstruction methods (Ordered-Subsets Expectation
Maximization (OSEM) and Filtered back projection (FBP)) was assessed for collimators that demonstrated
a better RC value.
Results: Five low-energy high-resolution (LEHR) collimators and one medium-energy general-purpose
(MEGP) collimator demonstrated superior RC values. These collimators had a high aspect ratio (holelength/hole-diameter). The maximum RC value without resolution correction was 64.9% when the image
was reconstructed with OSEM. The RC value improved to 79.7% when the resolution correction of CBC
was applied. When the resolution collection was applied, the RCs improved by approximately 1.2 times
when compared against those without the resolution correction. In terms of the reconstruction method, the
RC obtained using OSEM was statistically insignificant when compared to the RC using FBP. The
difference in the RC value with collimators decreased according to resolution correction.
Conclusion: The LEHR collimator with a high aspect ratio, and the OSEM with spatial resolution correction
were confirmed to be appropriate for DaT-SPECT imaging. In terms of the reconstruction method, CBC
was more favourable than FDR..
|5.||Shinji Amakusa, Koki Matsuoka, Shingo Baba, Tsuyoshi Yoshida, Masayuki Sasaki, Differences in edge artifacts between 68Ga- and 18F-PET images reconstructed using point spread function correction, Nuclear Medicine Communications, 10.1097/mnm.0000000000001079, 40, 11, 1166-1173, 2019.11.|
|6.||Akihiko Takahashi, Shingo Baba, Masayuki Sasaki, Assessment of collimators in radium-223 imaging with channelized Hotelling observer: a simulation study, Annals of Nuclear Medicine, 10.1007/s12149-018-1286-4, 32, 10, 649-657, 2018.12.|
|7.||The influence of minimal misalignment on the repeatability of PET images examined by the repositioning of point sources..|
|8.||Kei Wagatsuma, Keiichi Oda, Muneyuki Sakata, Motoki Inaji, Kenta Miwa, Masayuki Sasaki, Jun Toyohara, Kenji Ishii, Validation of scatter limitation correction to eliminate scatter correction error in oxygen-15 gas-inhalation positron emission tomography images, Nuclear Medicine Communications, 10.1097/mnm.0000000000000882, 39, 10, 936-944, 2018.10.|
|9.||Hashimoto N, Morita K, Tsutsui Y, Himuro K, Baba S, Sasaki M., Time-of-flight information improved the detectability of sub-centimeter sphere using clinical positron emission tomography/computed tomography scanner., J Nucl Med Technol., 10.2967/jnmt.117.204735., 39, 10, 268-273, J Nucl Med Technol. 2018 Sep;46(3):268-273., 2018.09.|
|10.||Naoki Hashimoto, Keishin Morita, Yuji Tsutsui, Kazuhiko Himuro, Shingo Baba, Masayuki Sasaki, Time-of-Flight Information Improved the Detectability of Subcentimeter Spheres Using a Clinical PET/CT Scanner, JOURNAL OF NUCLEAR MEDICINE TECHNOLOGY, 10.2967/jnmt.117.204735, 46, 3, 268-273, 2018.09, Recent advancements in clinical PET/CT scanners have improved the detectability of small lesions. However, the ideal reconstruction parameters for detecting small lesions have not yet been sufficiently clarified. The purpose of this study was to investigate the detectability of subcentimeter spheres using a clinical PET/CT scanner. Methods: We used a clinical PET/CT scanner to obtain the data of a National Electrical Manufacturers Association body phantom consisting of 6 small spheres (inner diameters, 4.0, 5.0, 6.2, 7.9, 10, and 37 mm) containing F-18 solution. The background activity was 2.65 kBq/mL, and the sphere-to-background ratio was 8. The PET data obtained for 2 and 120 min were reconstructed using ordered-subsets expectation maximization (OSEM), OSEM + point-spread function (PSF), and OSEM + time-of-flight (TOF) with voxel sizes of 2.04 x 2.04 x 2.00 mm (2-mm voxels) and 4.07 x 4.07 x 3.99 mm (4-mm voxels). A gaussian filter was not used. The image quality was evaluated by visual assessment, as well as by physical assessment of the detectability index and recovery coefficients. Results: According to the visual assessment, the detectability of the spheres improved using TOF and a longer acquisition. Using the OSEM+TOF model, the smallest visually detected spheres were 5 mm in diameter with a 120-min acquisition and 6 mm in diameter with a 2-min acquisition. According to physical assessment, the detectability of spheres 10 mm or smaller using the OSEM+TOF image was superior to that using the OSEM image. In addition, the detectability of each hot sphere and recovery coefficient with 2-mm voxels was superior to that with 4-mm voxels. Although OSEM+PSF images showed less background noise, detectability and the recovery coefficient were not improved for spheres 8 mm or smaller. Conclusion: The TOF model with 2-mm voxels improved the detectability of subcentimeter hot spheres on a clinical PET/CT scanner..|
|11.||Multicentre analysis of PET SUV using vendor-neutral software: the Japanese Harmonization Technology (J-Hart) study..|
|12.||Keishin Morita, Akira Maebatake, Rina Iwasaki, Yuki Shiotsuki, Kazuhiko Himuro, Shingo Baba, Masayuki Sasaki., Evaluation of the reconstruction parameters of brain dopamine transporter SPECT images obtained with a fan-beam collimator: A comparison with parallel-hole collimators., Asia Ocean J Nucl Med Biol., 10.22038/aojnmb.2018.10330, 6, 2, 120-128, 2018.02.|
|13.||Shinji Amakusa, Koki Matsuoka, Masayuki Kawano, Kiyotaka Hasegawa, Mio Ouchida, Ayaka Date, Tsuyoshi Yoshida, Masayuki Sasaki, Influence of region-of-interest determination on measurement of signal-to-noise ratio in liver on PET images, Annals of Nuclear Medicine, 10.1007/s12149-017-1215-y, 32, 1, 2018.01, Objective: On 18F-fluoro-2-deoxy-d-glucose (18F-FDG) positron emission tomography (PET), signal-to-noise ratio in the liver (SNRliver) is used as a metric to assess image quality. However, some regions-of-interest (ROIs) are used when measuring the SNRliver. The purpose of this study is to examine the different ROIs and volumes of interest (VOIs) to obtain a reproducible SNRliver. Methods: This study included 108 patients who underwent 18F-FDG-PET/CT scans for the purpose of cancer screening. We examined four different ROIs and VOIs; a 3-cm-diameter and a 4-cm-diameter circular ROI and a 3-cm-diameter and a 4-cm-diameter spherical VOI on the right lobe of the patients’ livers. The average of SUV (SUVmean), standard deviation (SD) of SUV (SUVSD), SNRliver and SD of the SNRliver obtained using ROIs and VOIs were then compared. Results: Although the SUVmean was not different among the ROIs and VOIs, the SUVSD was small with a 3-cm-diameter ROI. The largest SUVSD was obtained with a 4-cm-diameter spherical VOI. The SNRliver and the SD of the SNRliver with a 4-cm-diameter spherical VOI were the smallest, while those with a 3-cm-diameter circular ROI were the largest. These results suggest that a small ROI may be placed on a relatively homogeneous region not representing whole liver unintentionally. Conclusion: The SNRliver varied according to the shape and size of ROIs or VOIs. A 4-cm-diameter spherical VOI is recommended to obtain stable and reproducible SNRliver..|
|14.||Akihiko Takahashi, Kazuhiko Himuro, Shingo Baba, Yasuo Yamashita, Masayuki Sasaki., Comparison of TOF-PET and Bremsstrahlung SPECT Images of Yttrium-90: A Monte Carlo Simulation Study, Asia Oceania Journal of Nuclear Medicine and Biology, 10.22038, 6, 1, 24-31, 2018.01.|
|15.||Yuji Tsutsui, Shinichi Awamoto, Kazuhiko Himuro, Yoshiyuki Umezu, Shingo Baba, Masayuki Sasaki, Characteristics of Smoothing Filters to Achieve the Guideline Recommended Positron Emission Tomography Image without Harmonization, Asia Ocean J Nucl Med Biol., 10.22038/aojnmb.2017.26684.1186, 6, 1, 15-23, 2018.01, Objective: The aim of this study was to examine the effect of different smoothing filters on the image quality and harmonization of FDG-PET images.
Methods: We used a Biograph mCT PET scanner. A NEMA IEC body phantom was filled with 18F solution with a background activity of 2.65 kBq/mL and a sphere-to-background ratio of 4. PET images obtained with the Biograph mCT PET scanner were reconstructed using the ordered subsets expectation maximization (OSEM) algorithm with time-of-flight (TOF) models (iteration, 2; subset, 21); smoothing filters including Gaussian, Butterworth, Hamming, Hann, Parzen and Shepp-Logan filter with various full width at half maximum (FWHM) values (1-15 mm) were applied. The image quality was physically assessed according to percent contrast (QH,10), background variability (N10), standardized uptake value (SUV) and recovery coefficient (RC). The PET digital phantom was developed from the digital reference object (DRO) of the NEMA IEC body phantom smoothed using a Gaussian filter with 10 mm FWHM and defined as a reference image. The difference of the SUV between harmonized image and reference image was evaluated according to the root mean squared error (RMSE).
Results: The FWHM of the Gaussian, Butterworth, Hamming, Hann, Parzen and Shepp-Logan filter that satisfied the image quality of the FDG-PET/CT standardization guideline criteria were 8-12, 9-11, 9-13, 10-13, 9-11 and 12-15 mm, respectively. The FWHM of the Gaussian, Butterworth, Hamming, Hann, Parzen and Shepp-Logan filter that provided the smallest RMSE between PET images and the 3D digital phantom were 7, 8, 8, 8, 7 and 11 mm, respectively.
Conclusion: The optimal FWHM for image quality or harmonization depends on the type of smoothing filter that is applied..
|16.||Kei Wagatsuma, Keiichi Oda, Kenta Miwa, Motoki Inaji, Muneyuki Sakata, Jun Toyohara, Kiichi Ishiwata, Masayuki Sasaki, Kenji Ishii, Effects of a novel tungsten-impregnated rubber neck shield on the quality of cerebral images acquired using 15O-labeled gas, Radiological Physics and Technology, 10.1007/s12194-017-0414-5, 10, 4, 422-430, 2017.12, The present study aimed to validate the effects of a novel tungsten-impregnated rubber neck shield on the quality of phantom and clinical 15O-labeled gas positron emission tomography (PET) images. Images were acquired in the presence or absence of a neck shield from a cylindrical phantom containing [15O]H2O (phantom study) and from three individuals using [15O]CO2, [15O]O2 and [15O]CO gas (clinical study). Data were acquired in three-dimensional (3D) mode using a Discovery PET/CT 710. Values for cerebral blood flow, cerebral blood volume, oxygen extraction fraction, and cerebral metabolic rate of oxygen with and without the neck shield were calculated from 15O-labeled gas images. Arterial radioactivity and count characteristics were evaluated in the phantom and clinical studies. The coefficient of variance (CV) for the phantom study and the standard deviation (SD) for functional images were also analyzed. The neck shield decreased the random count rates by 25–59% in the phantom and clinical studies. The noise equivalent count rate (NECR) increased by 44–66% in the phantom and clinical studies. Random count rates and NECR in [15O]CO2 images significantly differed with and without the neck shield. The improvement in visual and physical image quality with the neck shield was not observed in the phantom and clinical studies. The novel neck shield reduced random count rate and improved NECR in a 3D PET study using 15O-labeled gas. The image quality with the neck shield was similar to that without the neck shield..|
|17.||Yasuo Kawata, Hidetaka Arimura, Koujirou Ikushima, Ze Jin, Kento Morita, Chiaki Tokunaga, Hidetake Yabu-uchi, Yoshiyuki Shioyama, Tomonari Sasaki, Hiroshi Honda, Masayuki Sasaki, Impact of pixel-based machine-learning techniques on automated frameworks for delineation of gross tumor volume regions for stereotactic body radiation therapy, PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS, 10.1016/j.ejmp.2017.08.012, 42, 141-149, 2017.10, The aim of this study was to investigate the impact of pixel-based machine learning (ML) techniques, i. e., fuzzy-c-means clustering method (FCM), and the artificial neural network (ANN) and support vector machine (SVM), on an automated framework for delineation of gross tumor volume (GTV) regions of lung cancer for stereotactic body radiation therapy. The morphological and metabolic features for GTV regions, which were determined based on the knowledge of radiation oncologists, were fed on a pixel-by-pixel basis into the respective FCM, ANN, and SVM ML techniques. Then, the ML techniques were incorporated into the automated delineation framework of GTVs followed by an optimum contour selection (OCS) method, which we proposed in a previous study. The three-ML-based frameworks were evaluated for 16 lung cancer cases (six solid, four ground glass opacity (GGO), six part-solid GGO) with the datasets of planning computed tomography (CT) and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT images using the three-dimensional Dice similarity coefficient (DSC). DSC denotes the degree of region similarity between the GTVs contoured by radiation oncologists and those estimated using the automated framework. The FCM-based framework achieved the highest DSCs of 0.79 +/- 0.06, whereas DSCs of the ANN-based and SVM-based frameworks were 0.76 +/- 0.14 and 0.73 +/- 0.14, respectively. The FCM-based framework provided the highest segmentation accuracy and precision without a learning process (lowest calculation cost). Therefore, the FCM-based framework can be useful for delineation of tumor regions in practical treatment planning. (C) 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved..|
|18.||Yasuhiro Maruoka, Shingo Baba, Takuro Isoda, Yoshiyuki Kitamura, Koichiro Abe, Masayuki Sasaki, Horoshi Honda, A functional scoring system based on salivary gland scintigraphy for evaluating salivary gland dysfunction secondary to 131I therapy in patients with differentiated thyroid carcinoma, Journal of Clinical and Diagnostic Research, 10.7860/JCDR/2017/27340.10431, 11, 8, TC23-TC28, 2017.08, Introduction: Radioiodine therapy with 131I (131I therapy) after total or near-total thyroidectomy has been established as an effective treatment for Differentiated Thyroid Carcinoma (DTC), but can induce dry mouth symptoms by salivary gland damage and impair the patients’ quality of life. Aim: To propose a functional scoring system based on Salivary Gland Scintigraphy (SGS) findings that evaluates development of salivary gland dysfunction secondary to 131I therapy in patients with DTC. Materials and Methods: This retrospective study evaluated the records of 279 DTC patients who underwent SGS after one or more round(s) of 131I therapy, using 370 MBqof 99mTc-pertechnetate. The SGS results were assessed using a novel functional scoring system in the Parotid Glands (PGs) and Submandibular Glands (SMGs) according to visual evaluations based on a three-point uptake score, Washout Rate (%WR) score after lemon-juice stimulation, and functional score. The scores were compared among pretreatment, low-dose (<
10 GBq), and high-dose (>
10 GBq) groups and among pretreatment, symptom-positive, and symptom-negative groups. Risk factors for dry mouth were analyzed by univariate and multivariate logistic regression analyses. Results: Dry mouth symptoms developed in 15.4% of the DTC patients after 131I therapy. The three-point uptake, %WR, and functional scores in both the PG and SMG were statistically significant between low-dose and high-dose groups, and between symptom-positive and symptom-negative groups. The PG/SMG functional scores were independent risk factors for dry mouth (odds ratio, 0.03 and 0.0007 respectively). Conclusion: SGS-based PG and SMG functional scores were effective biomarkers to objectively evaluate salivary gland dysfunction, with the high strength of association with dry mouth symptoms..
|19.||Yasuhiro Maruoka, Shingo Baba, Takuro Isoda, Yoshiyuki Kitamura, Koichiro Abe, Masayuki Sasaki, Hiroshi Honda, Association between volumetric analysis of lung metastases on F-18-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography and short-term progression after i-131 therapy for differentiated thyroid carcinoma, Indian Journal of Nuclear Medicine, 10.4103/ijnm.IJNM_43_17, 32, 3, 167-172, 2017.07, Purpose: Lung metastases (LMs) and their radioiodine uptake affect prognosis in patients with differentiated thyroid carcinoma (DTC). We herein investigate the value of metabolic tumor volume (MTV) in LMs on positron emission tomography/computed tomography (PET/CT) using 2-[F-18]-fluoro-2-deoxy-D-glucose (F-18 FDG PET/CT) in predicting short-term progression after initial I-131 therapy in DTC patients. Materials and Methods: We retrospectively evaluated 111 DTC patients with LMs. Diagnostic CT and I-131 scintigraphy were performed within 1 week of I-131 therapy. Maximum standardized uptake value (SUVmax) and total MTV (MTVtotal) were compared between patients with I-131-positive and I-131-negative LMs and between patients with and without short-term progression. Correlation analyses were performed between F-18 FDG PET/CT parameters and thyroglobulin (TG) level, and predictive factors for short-term progression were analyzed by logistic regression and receiver operating characteristic curve analysis.Results: Patients with short-term progression had significantly higher SUVmax and MTVtotal than those without. TG levels were significantly correlated with SUVmax (r = 0.21) and MTVtotal (r = 0.51) after I-131 therapy. MTVtotal showed significant association (χ2 = 16.5, odds ratio = 0.02) with short-term progression after initial I-131 therapy and had the highest predictive value of all the putative risk factors. Conclusions: MTVtotal in LMs on F-18 FDG PET/CT is an independent predictive factor with a high predictive value for short-term progression of DTC after initial I-131 therapy. It is recommended that F-18 FDG PET/CT be performed before planning therapy during the evaluation of DTC patients with LM..|
|20.||Toshioh Fujibuchi, Takatoshi Toyoda, Shingo Baba, Yoshiyuki Umezu, Isao Komiya, Masayuki Sasaki, Hiroshi Honda, Evaluation of the distribution of activation inside a compact medical cyclotron, Applied Radiation and Isotopes, 10.1016/j.apradiso.2017.02.045, 124, 27-31, 2017.06, The distribution of activation inside a compact medical cyclotron was evaluated by measuring 1 cm dose equivalent rates and γ-ray spectra. Analysis of the distribution of activation showed high activation at the deflector and the magnetic channel. Radionuclides 60Co, 57Co, 65Zn, and 54Mn were detected. Different radionuclides were generated from different components of the cyclotron, and low-activity radionuclides could be detected under low-background-radiation conditions..|
|21.||Yasuhiro Maruoka, Michinobu Nagao, Shingo Baba, Takuro Isoda, Yoshiyuki Kitamura, Yuzo Yamazaki, Koichiro Abe, Masayuki Sasaki, Kohtaro Abe, Hiroshi Honda, Three-dimensional fractal analysis of Tc-99m-MAA SPECT images in chronic thromboembolic pulmonary hypertension for evaluation of response to balloon pulmonary angioplasty: association with pulmonary arterial pressure, NUCLEAR MEDICINE COMMUNICATIONS, 10.1097/MNM.0000000000000673, 38, 6, 480-486, 2017.06, ObjectiveBalloon pulmonary angioplasty (BPA) is used for inoperable chronic thromboembolic pulmonary hypertension (CTEPH), but its effect cannot be evaluated noninvasively. We devised a noninvasive quantitative index of response to BPA using three-dimensional fractal analysis (3D-FA) of technetium-99m-macroaggregated albumin (Tc-99m-MAA) single-photon emission computed tomography (SPECT).Patients and methodsForty CTEPH patients who underwent pulmonary perfusion scintigraphy and mean pulmonary arterial pressure (mPAP) measurement by right heart catheterization before and after BPA were studied. The total uptake volume (TUV) in bilateral lungs was determined from maximum intensity projection Tc-99m-MAA SPECT images. Fractal dimension was assessed by 3D-FA. Parameters were compared before and after BPA, and between patients with post-BPA mPAP more than 30mmHg and less than or equal to 30mmHg. Receiver operating characteristic analysis was carried out.ResultsBPA significantly improved TUV (595204-885 +/- 214ml, P<0.001) and reduced the laterality of uptake (238 +/- 147-135 +/- 131ml, P<0.001). Patients with poor therapeutic response (post-BPA mPAP30mmHg, n=16) showed a significantly smaller TUV increase (P=0.044) and a significantly greater post-BPA fractal dimension (P<0.001) than the low-mPAP group. Fractal dimension correlated with mPAP values before and after BPA (P=0.013 and 0.001, respectively). A post-BPA fractal dimension threshold of 2.4 distinguished between BPA success and failure with 75% sensitivity, 79% specificity, 78% accuracy, and area under the curve of 0.85.Conclusion3D-FA using Tc-99m-MAA SPECT pulmonary perfusion scintigraphy enables a noninvasive evaluation of the response of CTEPH patients to BPA..|
|22.||Yuji Tsutsui, Masayuki Sasaki, Edge Artifacts in Point Spread Function-based PET Reconstruction in Relation to Object Size and Reconstruction Parameters., Asia Ocean J Nucl Med Biol., 10.22038/aojnmb.2017.8802., 5, 2, 134-143, 2017.02.|
|23.||Kitamura Yoshiyuki, Masayuki Sasaki, The Efficiency of Respiratory-gated 18F-FDG PET/CT in Lung Adenocarcinoma: Amplitude-gating Versus Phase-gating Methods., Asia Ocean J Nucl Med Biol., 10.22038/aojnmb.2016.7747., 5, 1, 30-36, 2017.01.|
|24.||TAKURO ISODA, Masayuki Sasaki, Influence of the Different Primary Cancers and Different Types of Bone Metastasis on the Lesion-based Artificial Neural Network0 Value Calculated by a Computer-aided Diagnostic System,BONENAVI, on Bone Scintigraphy Images., Asia Ocean J Nucl Med Biol., 10.22038/aojnmb.2016.7606., 5, 1, 49-55, 2017.01.|
|25.||Koujiro Ikushima, Hidetaka Arimura, Ze Jin, Hidetake Yabu-uchi, Jumpei Kuwazuru, Yoshiyuki Shioyama, Tomonari Sasaki, Hiroshi Honda, Masayuki Sasaki, Computer-assisted framework for machine-learning-based delineation of GTV regions on datasets of planning CT and PET/CT images, JOURNAL OF RADIATION RESEARCH, 10.1093/jrr/rrw082, 58, 1, 123-134, 2017.01, We have proposed a computer-assisted framework for machine-learning-based delineation of gross tumor volumes (GTVs) following an optimum contour selection (OCS) method. The key idea of the proposed framework was to feed image features around GTV contours (determined based on the knowledge of radiation oncologists) into a machine-learning classifier during the training step, after which the classifier produces the 'degree of GTV' for each voxel in the testing step. Initial GTV regions were extracted using a support vector machine (SVM) that learned the image features inside and outside each tumor region (determined by radiation oncologists). The leave-one-out-by-patient test was employed for training and testing the steps of the proposed framework. The final GTV regions were determined using the OCS method that can be used to select a global optimum object contour based on multiple active delineations with a LSM around the GTV. The efficacy of the proposed framework was evaluated in 14 lung cancer cases [solid: 6, ground-glass opacity (GGO): 4, mixed GGO: 4] using the 3D Dice similarity coefficient (DSC), which denotes the degree of region similarity between the GTVs contoured by radiation oncologists and those determined using the proposed framework. The proposed framework achieved an average DSC of 0.777 for 14 cases, whereas the OCS-based framework produced an average DSC of 0.507. The average DSCs for GGO and mixed GGO were 0.763 and 0.701, respectively, obtained by the proposed framework. The proposed framework can be employed as a tool to assist radiation oncologists in delineating various GTV regions..|
|26.||Hiroaki Shiba, Akihiko Takahashi, Shingo Baba, Kazuhiko Himuro, Yasuo Yamashita, Masayuki Sasaki, Analysis of the influence of In-111 on Y-90-bremsstrahlung SPECT based on Monte Carlo simulation, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-016-1112-9, 30, 10, 675-681, 2016.12, Y-90-ibritumomab tiuxetan (Zevalin) which is used for the treatment of malignant lymphomas can be used for SPECT imaging based on bremsstrahlung from Y-90 beta particles. However, gamma rays emitted by In-111, which is administered to evaluate the indication for the treatment, contaminate the Y-90 bremsstrahlung images. Our objective is to investigate the influence of In-111 on the Y-90 SPECT images using Monte Carlo simulation.
We used an in-house developed simulation code for the Monte Carlo simulation of electrons and photons (MCEP). Two hot spheres with diameters of 40 mm were put in an elliptical phantom. Both spheres ("sphere 1" and "sphere 2") were filled with Y-90 and In-111 mixed solutions. The activities of Y-90 in sphere 1 and sphere 2 were 241 and 394 kBq/mL, respectively, and the ones of In-111 were 8.14 and 13.3 kBq/mL, respectively. The background activity of Y-90 was 38.6 kBq/mL, whereas that of In-111 was 1.30 kBq/mL; moreover, the acquisition time was 30 min. Two energy windows were used: one is 90-190 keV included the In-111 photopeak; the other is 90-160 keV. To evaluate the quality of the SPECT images, the contrast recovery coefficient (CRC) and the constant noise ratio (CNR) of the SPECT images were derived.
For the energy window between 90 and 160 keV, the In-111 count was 74 % of the total. In that case, the CRC values were 30.1 and 30.7 % for "sphere 1" and "sphere 2", respectively, whereas the CNR values were 6.8 and 12.1, respectively. For the energy window between 90 and 190 keV, the In-111 count reached 85 % of the total count. The CRC and CNR values were 38.6 and 40.0 % and 10.6 and 19.4, respectively.
Our simulation study revealed that the cross talk between In-111 and Y-90 in SPECT imaging is rather serious. Even for the energy window excluding the In-111 photopeak, the count ratio of Y-90 was less than 30 % of the total. However, the influence of In-111 on Y-90-SPECT imaging cannot be ignored, and the count ratio because of In-111 is important to estimate the density of Y-90..
|27.||Takuro Isoda, Shingo BaBa, Yasuhiro Maruoka, Yoshiyuki Kitamura, Keiichiro Tahara, Masayuki Sasaki, Hiroshi Honda, Impact of patient age on the iodine/FDG "flip-flop" phenomenon in lung metastasis from thyroid cancer, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-016-1104-9, 30, 8, 518-524, 2016.10, Radioiodine therapy is an effective treatment for lung metastasis from thyroid cancer. However, cases of lung metastasis without iodine uptake are often encountered. In such cases, FDG accumulation in lung lesions is often observed. There is a reverse relationship between iodine and FDG accumulation in thyroid cancer lesions, the so-called "flip-flop" phenomenon. The aim of this study was to assess the relationship between patient age and the occurrence of the flip-flop phenomenon.
Eighty-six patients who underwent radioiodine therapy for lung metastasis were studied retrospectively (age 17-73 years; median 60 years; males:females 22:64). We compared the clinical data and imaging findings (size and FDG uptake of lung nodules) between patients with (n = 44) and without (n = 42) iodine uptake in lung metastasis.
Significantly more young patients showed iodine accumulation in lung metastasis than old patients (p = 0.0025). Lung metastases with larger size or greater FDG uptake showed no iodine uptake more frequently with significant difference (p = 0.015 and < 0.001, respectively). Among patients with FDG uptake in the lung metastasis, 57.1 % of young patients (< 60 years) and 24.3 % of the old patients (aeyen60 years) showed iodine uptake (p = 0.0029).
Higher patient age and lung nodules with large size or FDG accumulation are negative factors for iodine accumulation in lung metastases from thyroid cancer. In addition, our results show that young patients have a greater likelihood of iodine uptake even when FDG accumulates in lung metastasis, in contrast to old patients..
|28.||Automated PET-only quantification of amyloid deposition with adaptive template and empirically pre-defined ROI..|
|29.||The influence of respiratory motion on the cumulative SUV-volume histogram and fractal analyses of intratumoral heterogeneity in PET/CT imaging..|
|30.||Akihiko Takahashi, Kenta Miwa, Masayuki Sasaki, Shingo Baba, A Monte Carlo study on Ra-223 imaging for unsealed radionuclide therapy, MEDICAL PHYSICS, 10.1118/1.4948682, 43, 6, 2965-2974, 2016.06, Purpose: Radium-223 (Ra-223),an alpha-emitting radionuclide, is used in unsealed radionuclide therapy for metastatic bone tumors. The demand for qualitative Ra-223 imaging is growing to optimize dosimetry. The authors simulated Ra-223 imaging using an in-house Monte Carlo simulation code and investigated the feasibility and utility of Ra-223 imaging.
Methods: The Monte Carlo code comprises two modules,(HEXAGON). and (NAI) The (HEXAGON) code simulates the photon and electron interactions in the tissues and collimator, and the (NAI) code simulates the response of the NaI detector system. A 3D numeric phantom created using computed tomography images of a chest phantom was installed in the (HEXAGON) code. Ra-223 accumulated in a part of the spine, and three x-rays and 19. rays between 80 and 450 keV were selected as the emitted photons. To evaluate the quality of the Ra-223 imaging, the authors also simulated technetium-99m (Tc-99m) imaging under the same conditions and compared the results.
Results: The sensitivities of the three photopeaks were 147 counts per unit of source activity (cps MBq(-1); photopeak: 84 keV, full width of energy window: 20%), 166 cps MBq-1 (154 keV, 15%), and 158 cps MBq(-1) (270 keV, 10%) for a low-energy general-purpose (LEGP) collimator, and those for the medium-energy general-purpose (MEGP) collimator were 33, 13, and 8.0 cps MBq(-1), respectively. In the case of Tc-99m, the sensitivity was 55 cps MBq(-1) (141 keV, 20%) for LEGP and 52 cps MBq(-1) for MEGP. The fractions of unscattered photons of the total photons reflecting the image quality were 0.09 (84 keV), 0.03 (154 keV), and 0.02 (270 keV) for the LEGP collimator and 0.41, 0.25, and 0.50 for the MEGP collimator, respectively. Conversely, this fraction was approximately 0.65 for the simulated Tc-99m imaging. The sensitivity with the LEGP collimator appeared very high. However, almost all of the counts were because of photons that penetrated or were scattered in the collimator; therefore, the proportions of unscattered photons were small.
Conclusions: Their simulation study revealed that the most promising scheme for Ra-223 imaging is an 84-keV window using an MEGP collimator. The sensitivity of the photopeaks above 100 keV is too low for Ra-223 imaging. A comparison of the fractions of unscattered photons reveals that the sensitivity and image quality are approximately two-thirds of those for Tc-99m imaging. (C) 2016 American Association of Physicists in Medicine..
|31.||Miwa Kenta, Masayuki Sasaki, Evaluation of scatter limitation correction: a new method to correct photopenic artifacts caused by patient motion during whole-body PET/CT., Nucl Med Commun, 10.1097/MNM.0000000000000403., 30, 2, 147-154, 2016.05.|
|32.||The edge artifact in the point-spread function-based PET reconstruction at different sphere-to-background ratios of radioactivity..|
|33.||Akira Maebatake, Masayuki Sasaki, Evaluation of iterative reconstruction method and attenuation correction on brain dopamine transporter SPECT using anthropomorphic striatal phantom., Asia Ocean J Nucl Med Biol., 10.7508/aojnmb.2016.02.003, 4, 2, 72-80, 2016.02.|
|34.||Optimization of image reconstruction conditions with phantoms for brain FDG and amyloid PET imaging..|
|35.||Relationship between the image quality and noise-equivalent count in time-of-flight positron emission tomography..|
|36.||Yabuuchi H, Masayuki Sasaki, Hiroshi Honda, Anterior mediastinal solid tumours in adults: characterisation using dynamic contrast-enhanced MRI, diffusion-weighted MRI, and FDG-PET/CT, CLINICAL RADIOLOGY, 10.1016/j.crad.2015.07.004, 70, 11, 1289-1298, 2015.11.|
|37.||Influence of Statistical Fluctuation on Reproducibility and Accuracy of SUVmax and SUVpeak: A Phantom Study..|
|38.||[Harmonization of Standardized Uptake Value among Different Generation PET/ CT Cameras Based on a Phantom Experiment -Utility of SUV(peak)]..|
|39.||Norikazu Matsutomo, Masayuki Sasaki, Validation of the CT iterative reconstruction technique for low-dose CT attenuation correction for improving the quality of PET images in an obesity-simulating body phantom and clinical study, NUCLEAR MEDICINE COMMUNICATIONS, 10.1097/MNM.0000000000000326, 36, 8, 839-847, 2015.08.|
|40.||Norikazu Matsutomo, Masayuki Sasaki, Optimization of iterative reconstruction parameters with 3-dimensional resolution recovery, scatter and attenuation correction in I-123-FP-CIT SPECT, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-015-0987-1, 29, 7, 636-642, 2015.08.|
|41.||Hidetake Yabuuchi, Yoshio Matsuo, Takeshi Kamitani, Mikako Jinnnouchi, Masato Yonezawa, Yuzo Yamasaki, Michinobu Nagao, Satoshi Kawanami, Tatsuro Okamoto, Masayuki Sasaki, Hiroshi Honda, Detectability of T1a lung cancer on digital chest radiographs: an observer-performance comparison among 2-megapixel general-purpose, 2-megapixel medical-purpose, and 3-megapixel medical-purpose liquid-crystal display (LCD) monitors, ACTA RADIOLOGICA, 10.1177/0284185114544244, 56, 8, 943-949, 2015.08, Background: There has been no comparison of detectability of small lung cancer between general and medical LCD monitors or no comparison of detectability of small lung cancer between solid and part-solid nodules.
Purpose: To compare the detectabilities of T1a lung cancer on chest radiographs on three LCD monitor types: 2-megapixel (MP) for general purpose (General), 2-MP for medical purpose (Medical), and 3-MP-Medical.
Material and Methods: Radiographs from forty patients with T1aN0M0 primary lung cancer (27 solid nodules, 13 part-solid nodules) and 60 patients with no abnormalities on both chest X-ray and computed tomography (CT) were consecutively collected. Five readers assessed 100 cases for each monitor. The observations were analyzed using receiver operating characteristic (ROC) analysis. A jackknife method was used for statistical analysis. A P value of <0.05 was considered significant.
Results: The average AUC for all T1a lung cancer nodule detection using the 2-MP-General, 2-MP-Medical, and 3-MP-Medical LCD monitors were 0.86, 0.89, and 0.89, respectively; there were no significant differences among them. The average AUC for part-solid nodule detection using a 2-MP-General, 2-MP-Medical, and 3-MP-Medical LCD monitors were 0.77, 0.86, and 0.89, respectively. There were significant differences between the 2-MP-General and 2-MP-Medical LCD monitors (P = 0.043) and between the 2-MP-General and 3-MP-Medical LCD monitors (P = 0.027). There was no significant difference between the 2-MP-Medical and 3-MP-Medical LCD monitors. The average AUC for solid nodule detection using a 2-MP-General, 2-MP-Medical, and 3-MP-Medical LCD monitors were 0.90, 0.90, and 0.88, respectively; there were no significant differences among them. The mean AUC values for all and part-solid nodules of the low-experienced readers were significantly lower than those of the high-experienced readers with the 2 M-GP color LCD monitor (P < 0.05).
Conclusion: Detectability of part-solid nodules using a general-purpose LCD monitor was significantly lower than those using medical-purpose LCD monitors..
|42.||Miwa Kenta, Masayuki Sasaki, Performance characteristics of a novel clustered multi-pinhole technology for simultaneous high-resolution SPECT/PET, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-015-0966-6., 56, 3, 460-466, 2015.05.|
|43.||Akihiko Takahashi, Kazuhiko Himuro, Yasuo Yamashita, Isao Komiya, Shingo Baba, Masayuki Sasaki, Monte Carlo simulation of PET and SPECT imaging of Y-90, MEDICAL PHYSICS, 10.1118/1.4915545, 42, 4, 1926-1935, 2015.04, Purpose: Yittrium-90 (Y-90) is traditionally thought of as a pure beta emitter, and is used in targeted radionuclide therapy, with imaging performed using bremsstrahlung single-photon emission computed tomography (SPECT). However, because Y-90 also emits positrons through internal pair production with a very small branching ratio, positron emission tomography (PET) imaging is also available. Because of the insufficient image quality of Y-90 bremsstrahlung SPECT, PET imaging has been suggested as an alternative. In this paper, the authors present the Monte Carlo-based simulation-reconstruction framework for Y-90 to comprehensively analyze the PET and SPECT imaging techniques and to quantitatively consider the disadvantages associated with them.
Methods: Our PET and SPECT simulation modules were developed using Monte Carlo simulation of Electrons and Photons (MCEP), developed by Dr. S. Uehara. PET code (MCEP-PET) generates a sinogram, and reconstructs the tomography image using a time-of-flight ordered subset expectation maximization (TOF-OSEM) algorithm with attenuation compensation. To evaluate MCEP-PET, simulated results of F-18 PET imaging were compared with the experimental results. The results confirmed that MCEP-PET can simulate the experimental results very well. The SPECT code (MCEP-SPECT) models the collimator and NaI detector system, and generates the projection images and projection data. To save the computational time, the authors adopt the prerecorded Y-90 bremsstrahlung photon data calculated by MCEP. The projection data are also reconstructed using the OSEM algorithm. The authors simulated PET and SPECT images of a water phantom containing six hot spheres filled with different concentrations of Y-90 without background activity. The amount of activity was 163 MBq, with an acquisition time of 40 min.
Results: The simulated Y-90-PET image accurately simulated the experimental results. PET image is visually superior to SPECT image because of the lowbackground noise. The simulation reveals that the detected photon number in SPECT is comparable to that of PET, but the large fraction (approximately 75%) of scattered and penetration photons contaminates SPECT image. The lower limit of Y-90 detection in SPECT image was approximately 200 kBq/ml, while that in PET image was approximately 100 kBq/ml.
Conclusions: By comparing the background noise level and the image concentration profile of both the techniques, PET image quality was determined to be superior to that of bremsstrahlung SPECT. The developed simulation codes will be very useful in the future investigations of PET and bremsstrahlung SPECT imaging of Y-90. (C) 2015 American Association of Physicists in Medicine..
|44.||Maebatake A, Sato M, Kagami R, Yamashita Y, Komiya I, Himuro K, Shingo Baba, Masayuki Sasaki, An anthropomorphic phantom study of brain dopamine transporter SPECT images obtained using different SPECT/CT devices and collimators., J Nucl Med Technol, 43, 1, 41-46, 2015.03.|
|45.||Shiiba T, Nishii R, Masayuki Sasaki, Kihara Y, Tsuruta K, Maeda M, Junji Morishita, Assessment of the efficacy of early phase parameters by 123I-MIBG dynamic imaging for distinguishing Lewy body-related diseases from Parkinson's syndrome., Ann Nucl Med, 10.1007/s12149-014-0923-9., 29, 2, 149-156, 2015.02.|
|46.||Improvement in PET/CT image quality in overweight patients with PSF and TOF..|
|47.||Toshioh Fujibuchi, Akihiro Nohtomi, Shingo Baba, Masayuki Sasaki, Isao Komiya, Yoshiyuki Umedzu, Hiroshi Honda, Distribution of residual long-lived radioactivity in the inner concrete walls of a compact medical cyclotron vault room, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-014-0918-6, 29, 1, 84-90, 2015.01, Compact medical cyclotrons have been set up to generate the nuclides necessary for positron emission tomography. In accelerator facilities, neutrons activate the concrete used to construct the vault room; this activation increases with the use of an accelerator. The activation causes a substantial radioactive waste management problem when facilities are decommissioned. In the present study, several concrete cores from the walls, ceiling and floor of a compact medical cyclotron vault room were samples 2 years after the termination of operations, and the radioactivity concentrations of radionuclides were estimated.
Cylindrical concrete cores 5 cm in diameter and 10 cm in length were bored from the concrete wall, ceiling and floor. Core boring was performed at 18 points. The gamma-ray spectrum of each sample was measured using a high-purity germanium detector. The degree of activation of the concrete in the cyclotron vault room was analyzed, and the range and tendency toward activation in the vault room were examined.
Co-60 and Eu-152 were identified by gamma-ray spectrometry of the concrete samples. Eu-152 and Co-60 are produced principally from the stable isotopes of europium and cobalt by neutron capture reactions. The radioactivity concentration did not vary much between the surface of the concrete and at a depth of 10 cm. Although the radioactivity concentration near the target was higher than the clearance level for radioactive waste indicated in IAEA RS-G-1.7, the mean radioactivity concentration in the walls and floor was lower than the clearance level.
The radioactivity concentration of the inner concrete wall of the medical cyclotron vault room was not uniform. The areas exceeding the clearance level were in the vicinity of the target, but most of the building did not exceed the clearance levels..
|48.||Mikasa M, Akamatsu G, Taniguchi T, Kidera D, Kihara K, Matsuoka K, Amakusa S, Yoshida T, Masayuki Sasaki, Standardization of dual time point FDG-PET performed with different PET scanners using partial volume correction., Research and Reports in Nuclear Medicine, 5, 1-7, 2015.01.|
|49.||Jin, Ze, Hidetaka Arimura, Yoshiyuki Shioyama, Katsumasa Nakamura, Hidetake Yabuuchi, Hiroshi Honda, Ｈｉｄｅｋｉ Ｈｉｒａｔａ, Masayuki Sasaki, Computer-assisted delineation of lung tumor regions in treatment planning CT images with PET/CT image sets based on an optimum contour selection method, JOURNAL OF RADIATION RESEARCH, 10.1093/jrr/rru056, 55, 6, 1153-1162, 2014.11.|
|50.||Ze Jin, Hidetaka Arimura, Yoshiyuki Shioyama, Katsumasa Nakamura, Jumpei Kuwazuru, Taiki Magome, Hidetake Yabu-Uchi, Hiroshi Honda, Hideki Hirata, Masayuki Sasaki, Computer-assisted delineation of lung tumor regions in treatment planning CT images with PET/CT image sets based on an optimum contour selection method, JOURNAL OF RADIATION RESEARCH, 10.1093/jrr/rru056, 55, 6, 1153-1162, 2014.11, To assist radiation oncologists in the delineation of tumor regions during treatment planning for lung cancer, we have proposed an automated contouring algorithm based on an optimum contour selection (OCS) method for treatment planning computed tomography (CT) images with positron emission tomography (PET)/CT images. The basic concept of the OCS is to select a global optimum object contour based on multiple active delineations with a level set method around tumors. First, the PET images were registered to the planning CT images by using affine transformation matrices. The initial gross tumor volume (GTV) of each lung tumor was identified by thresholding the PET image at a certain standardized uptake value, and then each initial GTV location was corrected in the region of interest of the planning CT image. Finally, the contours of final GTV regions were determined in the planning CT images by using the OCS. The proposed method was evaluated by testing six cases with a Dice similarity coefficient (DSC), which denoted the degree of region similarity between the GTVs contoured by radiation oncologists and the proposed method. The average three-dimensional DSC for the six cases was 0.78 by the proposed method, but only 0.34 by a conventional method based on a simple level set method. The proposed method may be helpful for treatment planners in contouring the GTV regions..|
|51.||Yuji Tsutsui, Daisuke Kidera, Takafumi Taniguchi, Go Akamatsu, Isao Komiya, Yoshiyuki Umezu, Yoshiyuki Kitamura, Shingo Baba, Masayuki Sasaki, Accuracy of amplitude-based respiratory gating for PET/CT in irregular respirations, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-014-0870-5, 28, 8, 770-779, 2014.10, Objective We evaluated the accuracy of amplitude gating PET (AG-PET) compared with phase gating PET (PG-PET) in relation to respiratory motion patterns based on a phantom analysis.
Method We used a NEMA IEC body phantom filled with an F-18 solution with a 4: 1 sphere-to-background radioactivity ratio (12.6 and 2.97 kBq/mL). PET/CT scans were acquired in a motionless and moving state on a Biograph mCT. The respiratory movements were simulated by four different waveform patterns consisting of ideal breathing, breathing with a pause period, breathing with a variable amplitude and breathing with a changing baseline. AG-PET selects the narrow bandwidth containing 20 % of the respiratory cycle. PG-PET was reconstructed with five gates. The image quality was physically assessed using the percent contrast (Q(H,10mm)), background variability (N-10mm) recovery coefficient (RC), and sphere volumes.
Result In regular motion patterns with ideal breathing and breathing with a pause period, the Q(H,10mm), RC and sphere volumes were not different between AG-PET and PG-PET. In the variable amplitude pattern, the Q(H,10mm) of AG-PET was higher than that of PG-PET (35.8 vs 28.2 %), the RC of AG-PET was higher than that of PG-PET and sphere volume of AG-PET was smaller than that of PG-PET (6.4 vs 8.6 mL). In the changing baseline pattern, the Q(H,10mm) of AG-PET was higher than that of PG-PET (42.4 vs 16.7 %), the RC of AG-PET was higher than that of PG-PET and sphere volume of AG-PET was smaller than that of PG-PET (6.2 vs 9.8 mL). The N-10mm did not differ between AG-PET and PG-PET, irrespective of the motion pattern.
Conclusion Amplitude gating PET is considered to be more accurate than phase gating PET for examining unstable respiratory motion patterns, such as those involving a variable amplitude or changing baseline..
|52.||Yuki Yano, Hidetake Yabuuchi, Masayuki Sasaki, Detectability of simulated interstitial pneumonia on chest radiographs: comparison between irradiation side sampling indirect flat-panel detector and computed radiography, BRITISH JOURNAL OF RADIOLOGY, 10.1259/bjr.20140075, 87, 1040, 2014.08.|
|53.||Takuro Isoda, Shingo BaBa, Yasuhiro Maruoka, Yoshiyuki Kitamura, Akihiro Nishie, Masayuki Sasaki, Hiroshi Honda, Nabothian Cyst a Predominant Cause of False-Positive Iodine Uptake in Uterus Comparison of SPECT/CT and Pelvic MRI, CLINICAL NUCLEAR MEDICINE, 39, 8, 680-684, 2014.08, Purpose: Many cases of unexpected radioiodine uptake have been reported, including physiological uptake in healthy tissue and in both benign and malignant nonthyroidal lesions. However, iodine uptake in the uterus has not been well assessed. In this article, we systemically analyzed iodine uptake in the uterus and identified the site in which uptake occurred. Materials and Methods: Seventy-six female patients who underwent SPECT/CT from neck to pelvis were included in this study; 5 patients with uterine uptake received pelvic MRI. Iodine uptake in the uterus was diagnosed with SPECT/CT and compared with the findings of the MRI. Serum TSH level, administered dose of iodine-131 and number of radioiodine therapies were compared between the 2 groups with and without iodine uptake in the uterus.
Results: Twenty (26.3%) of 76 patients showed iodine uptake in the uterine cervix on SPECT/CT. It was difficult to distinguish the uptake in the uterus from that in the urinary bladder or rectum using only planar images. The patients with the uterine uptake were younger than those without (median age, 46.5 vs. 62, P = 0.011). There were no significant differences in serum TSH level, administered dose of iodine-131, or number of radioiodine therapies between the 2 groups. In all instances of the 5 patients who underwent pelvic MRI, iodine uptake in the uteri was located in nabothian cysts.
Conclusion: Iodine uptake in the uterus is frequently found if pelvic SPECT/CT is performed. Nabothian cysts are a predominant cause of iodine uptake in the uterine cervix..
|54.||Norikazu Matsutomo, Akio Nagaki, Masayuki Sasaki, Performance of myocardial perfusion imaging using multi-focus fan beam collimator with resolution recovery reconstruction in a comparison with conventional SPECT., Asia Oceania Journal of Nuclear Medicine and Biology, 2, 2, 111-119, 2014.08.|
|55.||Murata T, Kenta Miwa, Fujibuchi Toshioh, Masayuki Sasaki, Optimal radiation shielding for beta and bremsstrahlung radiation emitted by 89Sr and 90Y: validation by empirical approach and Monte Carlo simulations., Ann Nucl Med, 10.1007/s12149-014-0853-6., 28, 7, 617-622, 2014.08.|
|56.||Impact of Time-of-Flight PET/CT with a Large Axial Field of View for Reducing Whole-Body Acquisition Time..|
|57.||Shingo Baba, Takuro Isoda, Yasuhiro Maruoka, Yoshiyuki Kitamura, Masayuki Sasaki, Tsuyoshi Yoshida, Hiroshi Honda, Diagnostic and Prognostic Value of Pretreatment SUV in F-18-FDG/PET in Breast Cancer: Comparison with Apparent Diffusion Coefficient from Diffusion-Weighted MR Imaging, JOURNAL OF NUCLEAR MEDICINE, 10.2967/jnumed.113.129395, 55, 5, 736-742, 2014.05, In oncology, the apparent diffusion coefficient (ADC) measured by diffusion-weighted MR imaging (DWI) and the standardized uptake value (SUV) from F-18-FDG PET have similar clinical applications. The purpose of this study was to assess the correlation between the ADC and SUV and compare their potential in the diagnosis and prediction of prognosis in breast tumors. Methods: Seventy-nine female patients (age range, 19-69 y; average, 49.1 y) with 83 pathologically proven breast tumors were recruited. The diagnoses consisted of 70 malignant breast tumors (65 cases of invasive ductal carcinoma, 1 of medullary carcinoma, 1 of mucinous carcinoma, 1 of squamous cell carcinoma, and 2 of micropapillary carcinoma) and 13 benign breast tumors (4 cases of fibroadenoma, 4 of mastopathy, 3 of adenosis with atypia, and 2 of benign phyllodes tumor). All patients underwent mammary gland MR imaging with DWI and 18F-FDG PET within a 2-wk interval. The patients' ADCs and SUVs were measured within the tumor by DWI and F-18-FDG PET, respectively. For the malignant tumors, we evaluated the relationships among ADC, SUV, histopathologic appearance, and long-term prognosis. Results: A significant difference (P < 0.05) was observed in both parameters (ADC and SUV) between the benign and malignant breast tumors, and the difference was more significant when we introduced a new parameter, SUV/ADC. There was a weak inverse correlation between ADC and SUV (r = -0.36; P = 0.06) among the total tumors; however, this correlation was not significant within the group of malignant tumors. High SUV was found to correlate with larger tumor size, higher nuclear grade, and the triple-negative hormonal receptor profile. High ADC was revealed to be correlated with negative progesterone receptor and positive human epidermal growth factor receptor 2 profile. Higher SUVs also showed a correlation with poor prognosis. No correlation was seen between ADC and prognosis. Conclusion: Both SUV and ADC are helpful parameters in differentiating benign from malignant breast tumors. The use of SUV and ADC in combination may help in the diagnosis because of their inverse relationship. High preoperative SUV was associated with poor prognosis, but the contribution of ADC to prognosis prediction was small..|
|58.||Kenta Miwa, Masayuki Sasaki, FDG uptake heterogeneity evaluated by fractal analysis improves the differential diagnosis of pulmonary nodules, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2013.12.020, 83, 4, 715-719, 2014.04, Purpose: The present study aimed to determine whether fractal analysis of morphological complexity and intratumoral heterogeneity of FDG uptake can help to differentiate malignant from benign pulmonary nodules.
Materials and methods: We retrospectively analyzed data from 54 patients with suspected non-small cell lung cancer (NSCLC) who were examined by FDG PET/CT. Pathological assessments of biopsy specimens confirmed 35 and 19 nodules as NSCLC and inflammatory lesions, respectively. The
morphological fractal dimension (m-FD), maximum standardized uptake value (SUVmax) and density
fractal dimension (d-FD) of target nodules were calculated from CT and PET images. Fractal dimension
is a quantitative index of morphological complexity and tracer uptake heterogeneity; higher values indicate increased complexity and heterogeneity.
Results: The m-FD, SUVmax and d-FD significantly differed between malignant and benign pulmonary nodules (p < 0.05). Although the diagnostic ability was better for d-FD than m-FD and SUVmax, the difference did not reach statistical significance. Tumor size correlated significantly with SUVmax (r =
0.51, p < 0.05), but not with either m-FD or d-FD. Furthermore, m-FD combined with either SUVmax or d-FD improved diagnostic accuracy to 92.6% and 94.4%, respectively.
Conclusion: The d-FD of intratumoral heterogeneity of FDG uptake can help to differentially diagnose malignant and benign pulmonary nodules. The SUVmax and d-FD obtained from FDG-PET images provide different types of information that are equally useful for differential diagnoses. Furthermore, the morphological complexity determined by CT combined with heterogeneous FDG uptake determined by PET improved diagnostic accuracy..
|59.||Go Akamatsu, Masayuki Sasaki, Influences of point-spread function and time-of-flight reconstructions on standardized uptake value of lymph node metastases in FDG-PET, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2013.09.030, 83, 1, 226-230, 2014.01.|
|60.||Mana Akamatsu, Go Akamatsu, Masayuki Sasaki, Influences of reconstruction and attenuation correction in brain SPECT images obtained by the hybrid SPECT/CT device: evaluation with a 3-dimensional brain phantom., Asia Oceania Journal of Nuclear Medicine and Biology, 2, 1, 24-29, 2(1): 24-29., 2014.01.|
|61.||Go Akamatsu, Katsuhiko Mitsumoto, Takafumi Taniguchi, Yuji Tsutsui, Shingo Baba, Masayuki Sasaki, Influences of point-spread function and time-of-flight reconstructions on standardized uptake value of lymph node metastases in FDG-PET, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2013.09.030, 83, 1, 226-230, 2014.01, Purpose: The purpose of this study was to investigate the effects of point-spread function (PSF) and time-of-flight (TOF) on the standardized uptake value (Shy) of lymph node metastasis in FDG-PET/CT.
Materials and methods: This study evaluated 41 lymph node metastases in 15 patients who had undergone F-18-FDG PET/CT. The lesion diameters were 2.5 cm or less. The mean short-axis diameter of the lymph nodes was 10.5 +/- 3.7 mm (range 4.6-22.8 mm). The PET data were reconstructed with baseline OSEM algorithm, with OSEM + PSF, with OSEM + TOF and with OSEM + PSF + TOF. A semi-quantitative analysis was performed using the maximum and mean SUV of lymph node metastases (SUVmax and SUVmean) and mean SUV of normal lung tissue (SUVlung). We also evaluated image quality using the signal-to-noise ratio in the liver (SNRliver)).
Results: Both PSF and TOF increased the SUV of lymph node metastases. The combination of PSF and TOF increased the SUVmax by 43.3% and the SUVmean by 31.6% compared with conventional OSEM. By contrast, the SUVlung was not influenced by PSF and TOF. TOF significantly improved the SUVliver.
Conclusion: PSF and TOF both increased the SUV of lymph node metastases. Although PSF and TOF are considered to improve small-lesion detectability, it is important to be aware that PSF and TOF influence the accuracy of quantitative measurements. (C) 2013 Elsevier Ireland Ltd. All rights reserved..
|62.||Yasuhiro Maruoka, Masayuki Sasaki, Usefulness of partial volume effect-corrected F-18 FDG PET/CT for predicting I-131 accumulation in the metastatic lymph nodes of patients with thyroid carcinoma, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-013-0767-8, 27, 10, 873-879, 2013.12.|
|63.||Usefulness of partial volume effect-corrected F-18 FDG PET/CT for predicting I-131 accumulation in the metastatic lymph nodes of patients with thyroid carcinoma..|
|64.||Yuki Yano, Hidetake Yabuuchi, Nobukazu Tanaka, Junji Morishita, Tsutomu Akasaka, Yoshio Matsuo, Shunya Sunami, Takeshi Kamitani, Mikako Jinnouchi, Yuzo Yamasaki, Michinobu Nagao, Masayuki Sasaki, Detectability of simulated pulmonary nodules on chest radiographs: Comparison between irradiation side sampling indirect flat-panel detector and computed radiography, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2013.05.036, 82, 11, 2050-2054, 2013.11, Objective: To compare the detectability of simulated pulmonary nodules on chest radiographs between an irradiation side sampling indirect flat-panel detector (ISS-FPD) and computed radiography (CR).
Materials and methods: This study was an observer performance study. Simulated pulmonary nodules of 8 mm in diameter were superimposed on an anthropomorphic chest phantom. Chest radiographs were acquired under 2 exposure levels (4 and 3.2 mAs) with the ISS-FPD and the CR. Six thoracic radiologists evaluated all 40 images (10 patterns x 2 different exposure doses x 2 different systems) for the presence or absence of a lesion over each of 12 defined areas on a 3-megapixel monochrome liquid-crystal display. Receiver operating characteristic (ROC) curves were obtained for observation in predefined 480 areas. A jackknife method was used for statistical analysis. Differences with a P value of <0.05 were considered significant.
Results: The analysis of the observer detection of simulated pulmonary nodules showed larger areas under the ROC curve (AUC) by the ISS-FPD than by the CR. There was a statistically significant difference between the two systems at 3.2 mAs (P = 0.0330).
Conclusion: The ISS-FPD was superior to the CR for the detection of simulated pulmonary nodules at 3.2 mAs. (C) 2013 Elsevier Ireland Ltd. All rights reserved..
|65.||Benefits of point-spread function and time of flight for PET/CT image quality in relation to the body mass index and injected dose..|
|66.||Yoshiyuki Kitamura, Koichiro Abe, Akio Sakamoto, Shingo Baba, Takuro Isoda, Yasuhiro Maruoka, Yoshio Matsuo, Kubo Y, Hiroshi Nishimura, Masayuki Sasaki, Hiroshi Honda, Malignant triton tumor in the abdominal wall: a case report, Advances in Molecular Imaging (AMI) ., 10.4236/ami.2013.32002,, Advances in Molecular Imaging (AMI) . 2013; 3(2): 9-13. DOI: 10.4236/ami.2013.32002,, 2013.02, Advances in Molecular Imaging (AMI) . 2013; 3(2): 9-13. DOI: 10.4236/ami.2013.32002,.|
|67.||Nobukazu Tanaka, Yuki Yano, Hidetake Yabuuchi, Tsutomu Akasaka, Masayuki Sasaki, Masafumi Ohki, Junji Morishita, Basic imaging properties of an indirect flat-panel detector system employing irradiation side sampling (ISS) technology for chest radiography: Comparison with a computed radiographic system, Radiological Physics and Technology, 10.1007/s12194-012-0184-z, 6, 1, 162-169, Radiol Phys Technol. 2013 Jan;6(1):162-9. doi: 10.1007/s12194-012-0184-z. Epub 2012 Nov 10., 2013.01, The image quality and potential usefulness for patient skin-dose reduction of a newly developed flat-panel detector (FPD) system employing irradiation side sampling (ISS) were investigated and compared to a conventional computed radiography (CR) system. We used the X-ray beam quality of RQA 9 as noted in the standard evaluation method by the International Electrotechnical Commission 62220-1 to evaluate the image quality of the detector for chest radiography. The presampled modulation transfer function (MTF) of the ISS-FPD system was slightly higher than that of the CR system in the horizontal direction at more than 2.2 cycles/mm. However, the presampled MTF of the ISS-FPD system was slightly lower than that of the CR system in the vertical direction. The Wiener spectrum of the ISS-FPD system showed a 50-65 % lesser noise level than that of the CR system under the same exposure condition. The detective quantum efficiency of the ISS-FPD system was at least twice as great as that of the CR system. We conclude that the ISS-FPD system has the potential to reduce the patient skin dose compared to a conventional CR system for chest radiography. © 2012 Japanese Society of Radiological Technology and Japan Society of Medical Physics..|
|68.||Yasuhiro Maruoka, Koichiro Abe, Shingo Baba, Takuro Isoda, Hirofumi Sawamoto, Yoshitaka Tanabe, Masayuki Sasaki, Hiroshi Honda, Incremental Diagnostic Value of SPECT/CT with I-131 Scintigraphy after Radioiodine Therapy in Patients with Well-differentiated Thyroid Carcinoma, RADIOLOGY, 10.1148/radiol.12112108, 265, 3, 902-909, Radiology. 2012 Dec;265(3):902-9. doi: 10.1148/radiol.12112108. Epub 2012 Sep 25., 2012.12, Purpose: To retrospectively determine the incremental diagnostic value of adding single photon emission computed tomography/computed tomography (SPECT/CT) to whole-body scintigraphy with iodine 131 (I-131) compared with scintigraphy alone after radioiodine therapy in patients with well-differentiated thyroid carcinoma.
Materials and Methods: This retrospective study was institutional review board approved; written informed consent was waived. The study included 147 patients (94 female, 53 male patients; mean age, 51 years) with well-differentiated thyroid carcinoma treated with radioiodine therapy between October 2009 and August 2010. Whole-body scintigraphy and SPECT/CT were performed on the same day in all patients receiving radioiodine therapy. Each radioactive focus at whole-body scintigraphy was classified as positive or equivocal with respect to thyroid bed, lymph node, and distant metastasis uptake. Differences between whole-body scintigraphy and SPECT/CT findings were assessed with the generalized McNemar test.
Results: At SPECT/CT, origin was clearly determined of all five "hot spots" in the thyroid bed (remnant thyroid tissue or metastatic lymph node) that were judged as equivocal at whole-body scintigraphy. Interpretation of 24 (22.2%) of 108 radioactive foci for lymph node metastases was changed with SPECT/CT (P < .0001). One of 85 foci that were thought to be positive findings at whole-body scintigraphy turned out to be a negative finding (false-positive finding), and 13 and seven of 20 equivocal foci at whole-body scintigraphy were positive and negative findings, respectively, after adding SPECT/CT findings. Three false-negative findings at whole-body scintigraphy were corrected with SPECT/CT. For the detection of distant metastasis, the interpretations of 21 (40%) of 52 foci were corrected with SPECT/CT (P < .0001). One of 32 foci thought to be a positive finding at whole-body scintigraphy was a negative finding, and 11 and nine of 20 equivocal foci at whole-body scintigraphy were positive and negative findings, respectively, after SPECT/CT. At a patient-based analysis, SPECT/CT findings helped change the clinical staging in nine (6.1%) of 147 patients and therapeutic planning in three (2.0%) of 147 patients.
Conclusion: SPECT/CT improved detection and localization of 131I accumulation in lymph node metastases and distant metastases, compared with whole-body scintigraphy. (C) RSNA, 2012.
|69.||Yasuhiro Maruoka, Koichiro Abe, Shingo Baba, Takuro Isoda, Yoshio Matsuo, Yuichiro Kubo, Shinji Ogawa, Tokujiro Yano, Masayuki Sasaki, Hiroshi Honda, A case of pulmonary choriocarcinoma metastasis with unusual FDG-PET and CT findings: correlation with pathology, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-012-0644-x, 26, 10, 835-839, Ann Nucl Med. 2012 Dec;26(10):835-9. doi: 10.1007/s12149-012-0644-x. Epub 2012 Aug 15., 2012.12, A 26-year-old female who had had a hydatidiform mole at 20 years of age showed high levels of serum human chorionic gonadotropin. Because pelvic ultrasound did not show any gestational sac in her uterus, she was suspected to have had an extrauterine pregnancy and a spontaneous abortion. About 6 months later, a pulmonary nodule in the patient's right upper lung field was found on a routine chest X-ray film. Contrast- enhanced CT scans revealed a solitary lobulated nodule 2.0 x 1.3 x 3.0 cm in diameter in the S2 segment of the right lung. CT suggested a vessel malformation. Positron emission tomography using 2-deoxy-2-[F-18]fluoro-d-glucose (FDG-PET) was performed and showed weak FDG accumulation (SUVmax = 2.0) in the nodule, which did not positively indicate malignancy. Because a follow-up CT showed a rapid increase in the size of the nodule, partial resection of S2 segment in the right upper lobe was performed. The histopathological diagnosis was a metastasis from choriocarcinoma. The tumor consisted largely of necrosis and hemorrhage, and it was considered to be a major cause of the unusual FDG-PET and CT findings..|
|70.||Improvement in PET/CT image quality with a combination of point-spread function and time-of-flight in relation to reconstruction parameters..|
|71.||Shinmura A, Koichiro Abe, Shingo Baba, Takuro Isoda, Yasuhiro Maruoka, Yasukawa F, Kiryu H, Masayuki Sasaki, Hiroshi Honda, Masutaka Furue, FDG PET/CT Findings in Acquired Perforating Dermatosis., Clin Nucl Med., doi: 10.1097/PCR.0b013e3182675159., Clin Nucl Med. 2012 Oct;37(10):997-1000. doi: 10.1097/PCR.0b013e3182675159., 2012.10, Clin Nucl Med. 2012 Oct;37(10):997-1000. doi: 10.1097/PCR.0b013e3182675159..|
|72.||Kimie Asao, Akihiro Takaki, Mitsuhiro Tominaga, Masayuki Sasaki, The interpolated projection data estimation method improves the image quality of myocardial perfusion SPECT with a short acquisition time, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-011-0548-1, 26, 2, 123-130, 26 (2):123–130. Epub 2011 Oct 28., 2012.02, The interpolated projection data estimation processing (IPDE) method increases the amount of projection data by interpolation of the projection data. We examined the usefulness of the IPDE method for Tl-201 myocardial perfusion imaging (MPI) single photon emission computed tomography (SPECT) with a short acquisition time.
Forty patients with suspected ischemic heart disease underwent stress Tl-201-MPI SPECT. Both stress and delayed images were acquired with 4 cycles of 360A degrees continuous rotation with a 90-direction setting for 14 min. The projection data used for reconstruction were 1) all cycle data (Tl-90-14min), 2) 2 cycles of data (Tl-90-7min), and 3) 2 cycles of data processed using the IPDE method (Tl-180IPDE-7min). This study compared the detection of the perfusion defect by the uptake score and the image quality of Tl-201-MPI SPECT using the normalized mean square error (NMSE).
The uptake score of Tl-180IPDE-7min was significantly more concordant with Tl-90-14min in comparison to the Tl-90-7min (p < 0.05). The NMSE of the Tl-180IPDE-7min (1.85 +/- A 1.06%) was significantly lower than that of the Tl-90-7min (2.07 +/- A 1.24%) (p < 0.05). The degree of improvement by the IPDE method was significantly greater for the delayed Tl-201-MPI SPECT than for the stress Tl-201-MPI SPECT (p < 0.05).
The IPDE method improved the image quality and secured the diagnostic ability of Tl-201-MPI SPECT for a short acquisition time. Furthermore, the IPDE method is a simple software program that does not require any expensive equipment or use advanced algorithms. These results suggest that the IPDE method may be useful as an adjunctive method for shortening the acquisition time of Tl-201-MPI SPECT..
|73.||Katsuhiko Mitsumoto, Koichiro Abe, Yuichi Sakaguchi, Tiejiao Zhang, Yosuke Tachiya, Nobuyoshi Ohya, Shingo Baba, Masayuki Sasaki, Determination of the optimal acquisition protocol of breath-hold PET/CT for the diagnosis of thoracic lesions, NUCLEAR MEDICINE COMMUNICATIONS, 10.1097/MNM.0b013e32834bbda7, 32, 12, 1148-1154, 32(12):1148-54. Epub 2011 Sep 30., 2011.12, Objective The aim of this study was to determine the optimal acquisition scan protocol for deep inspiration breath-hold (BH) fluoro-2-deoxy-D-glucose positron emission tomography (PET) for the examination of thoracic lesions.
Methods We studied 32 thoracic lesions in 21 patients. Whole-body PET/computed tomography (CT) scanning with free breathing (FB) was performed for 3 min per bed position, followed by a BH-CT and five BH-PET for 20 s each. Summed BH images with total acquisition times of 40, 60, 80 and 100 s were generated (BH x 2, BH x 3, BH x 4 and BH x 5, respectively). The displacements between PET and CT images, the lesion volume of the PET image, the maximum standardized uptake value (SUVmax) and the quality of the PET image were assessed in relation to the clinical characteristics of each patient and the summation of the BH-PET images.
Results BH-PET decreased the tumor volume significantly (FB: 7.23 +/- 9.70 cm(3), BH x 5: 4.71 +/- 5.14 cm(3), P < 0.01) and increased the SUVmax (FB: 6.27 +/- 5.41, BH x 5: 7.53 +/- 6.28, P < 0.01). The displacement between the PET and CT images was improved significantly in the BH scans (FB: 0.77 +/- 0.53 cm, BH x 5: 0.36 +/- 0.24 cm, P < 0.01). In addition, aging and lung function of patients influenced the reproducibility of BH-PET. The summed BH-PET images, obtained by summation of three or more BH-PET images (total acquisition time of 60 s or more), achieved good image quality.
Conclusion BH-PET/CT improved the misregistration between PET and CT images and increased the SUVmax of thoracic lesions. The recommended number of BH-PET images for summation with 20 s of acquisition time is three or more. Nucl Med Commun 32: 1148-1154 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins. Nuclear Medicine Communications 2011, 32: 1148-1154.
|74.||Zhang T, Tachiya Y, Sakaguchi Y, Mitsumoto K, Mitsumoto T, Ohya N, Sasaki M., Phantom study on three-dimensional target volume delineation by PET/CT-based auto-contouring., Fukuoka Acta Medica., 101(11): 238 – 246., 2010.11.|
|75.||Yuichi Sakaguchi, Noriko Mizoguchi, Tatsuya Mitsumoto, Katsuhiko Mitsumoto, Kazuhiko Himuro, Nobuyoshi Ohya, Koichiro Kaneko, Shingo Baba, Koichiro Abe, Yoshihiko Onizuka, Masayuki Sasaki, A simple table lookup method for PET/CT partial volume correction using a point-spread function in diagnosing lymph node metastasis, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-010-0401-y, 24, 8, 585-591, 24 (8):585–591., 2010.10, Objective We evaluated the partial volume effect in PET/CT images and developed a simple correction method to address this problem.
Methods Six spheres and the background in the phantom were filled with F-18 and we thus obtained 4 different sphere-to-background (SB) ratios. Thirty-nine cervical lymph nodes in 7 patients with papillary thyroid carcinoma (15 malignant and 24 benign) were also examined as a preliminary clinical study. First, we developed recovery coefficient (RC) curves normalized to the maximum counts of the 37-mm sphere. Next, we developed a correction table to determine the true SB ratio using three parameters, including the maximum counts of both the sphere and background and the lesion diameter, by modifying the approximation formula of the RC curves including the point-spread function correction. The full width at half maximum in this formula is estimated with the function of the SB ratio.
Results In the phantom study, a size-dependent underestimation of the radioactivity was observed. The degree of decline of RC was influenced by the SB ratio. In preliminary clinical examination, the difference in the SUV(max) between malignant and benign LNs thus became more prominent after the correction. The PV correction slightly improved the diagnostic accuracy from 95 to 100%.
Conclusions We developed a simple table lookup correction method for the partial volume effect of PET/CT. This new method is considered to be clinically useful for the diagnosis of cervical LN metastasis. Further examination with a greater number of subjects is required to corroborate its clinical usefulness..
|76.||Mari Yakabe, Shuji Sakai, Hidetake Yabuuchi, Yoshio Matsuo, Takeshi Kamitani, Taro Setoguchi, Mayumi Cho, Masafumi Masuda, Masayuki Sasaki, Effect of Dose Reduction on the Ability of Digital Mammography to Detect Simulated Microcalcifications, JOURNAL OF DIGITAL IMAGING, 10.1007/s10278-009-9203-y, 23, 5, 520-526, 23(5):520-6, 2010.10, The purpose of this article was to report the relationship between radiation dose and the ability of sentence digital mammography to detect microcalcifications. All images were acquired by computed radiography and an anthropomorphic breast phantom. The tube voltage and anode/filter combination used were 28 kVp and Mo/Mo. Simulated microcalcifications with an approximate diameter of 250-350 mu m were positioned on the phantom. Groups of six microcalcifications were arranged in one of two patterns, a line cluster 1 cm long or a hexagonal cluster 4 mm wide. One of the six microcalcifications was removed to create a negative control. Each cluster was placed on 25 different points. Four levels of milliampere-second (mAs) values were applied: 100%, 50%, 25%, and 12.5%. Five staff radiologists participated in an observer performance test. All observers used a workstation with a 3-megapixel monochrome LCD monitor. The areas under the receiver-operating characteristics curves (AUC) were used to compare diagnostic performance among the four doses. The overall AUC scores were 0.97 with 100% mAs, 0.93 (n.s.) with 50%, 0.90 (p < 0.05) with 25%, and 0.81 (p < 0.01) with 12.5% mAs. Among the negative series, the percentage of images on which observers were able to identify the removed microcalcification point decreased from 88.8% with 100% mAs to 83.6% (n.s.) with 50%, 74.8% (p < 0.001) with 25%, and 67.2% (p < 0.001) with 12.5% mAs. A certain level of dose reduction in digital mammography may be an option..|
|77.||Y. Sakaguchi, T. Mitsumoto, T. Zhang, K. Mitsumoto, Y. Tachiya, N. Ohya, M. Sasaki, Importance of gated CT acquisition for the quantitative improvement of the gated PET/CT in moving phantom, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-010-0388-4, 24, 7, 507-514, 24 (7): 507-514, 2010.08, The aim of this study was to investigate the utility of gated PET/CT and CT attenuation correction (AC) for the quantitation of radioactivity.
An ellipse phantom containing six spheres, ranging from 10 to 37 mm in diameter, was filled with 36.7 kBq/mL of F-18. The respiratory motion was simulated by a motor-driven plastic platform to move the phantom with a displacement of 2 cm in the craniocaudal direction at a frequency of 15/min. With the phantom at rest, PET/CT data were acquired and used as a standard (nonmotion). With the phantom in motion, PET data were acquired in both the static and gated modes (sPET and gPET, respectively). Helical CT (HCT), slow CT (SCT), average CT (ACT), and four-dimensional CT (4DCT) were acquired and used to correct attenuation. On both PET and CT images, the maximum radioactivity, dimensions, and CT numbers were measured on the central slices.
In nonmotion, recovery coefficients whose spheres were 22 mm or smaller gradually decreased. Regarding motion, the PET counts of the spheres in the static acquisition were lower than those acquired in nonmotion with either type of CTAC (sPET-HCT: -43.8%, sPET-SCT: -51.4%, sPET-ACT: -49.5%). Gated acquisition of PET significantly improved the PET counts (gPET-HCT: -30.1%) (p < 0.05), while additional gated acquisition of CT significantly improved them further (gPET-4DCT: -15.2%) (p < 0.01). The dimensions of sPET were overestimated, but those of gPET were close to the standard values. The SCT significantly overestimated the dimensions, and the water density area decreased (p < 0.01). The 4DCT images were similar to the HCT images.
In respiratory motion, PET acquisition in the static mode underestimated the radioactivity and overestimated the dimensions. Neither SCT nor ACT improved these errors. Although PET acquisition in the gated mode improved the quantification of PET/CT images, the additional gated CT acquisition using 4DCT is required for further improvement..
|78.||Koichiro Kaneko, Koichiro Abe, Shingo Baba, Yoshitaka Tanabe, Hidetake Yabuuchi, Masamitsu Hatakenaka, Masayuki Sasaki, Hiroshi Honda, Can calcification predict I-131 accumulation on metastatic lymph nodes in papillary thyroid carcinoma patients receiving I-131 therapy? Comparison of CT, I-131 WBS and F-18-FDG PET/CT, EUROPEAN RADIOLOGY, 10.1007/s00330-009-1557-5, 20, 2, 477-483, Epub, 2010.02, The aim of this study was to clarify the predictive significance of nodal calcification in terms of the therapeutic option of I-131 therapy in papillary thyroid carcinoma (PTC) patients.
We reviewed 19 computed tomography (CT) examinations of PTC patients on receiving I-131 therapy for the presence of nodal calcification, and compared the I-131 whole-body scintigraphy and F-18-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/CT findings. The metastatic lymph nodes (mLNs) were divided into three groups: A, those with calcification; B, those without calcification but belonging to patients who had calcified mLNs; C, those without calcification and belonging to patients who had no calcified mLNs. The incidences of I-131 accumulation and maximum standardised uptake values (SUV max) in the three groups were compared.
A total of 70 mLNs were evaluated. Twelve mLNs belonged to group A, 13 to group B and 45 to group C. The incidences of I-131 accumulation were significantly higher in groups A (100%) and B (100%) than in group C (11.1%) (p < 0.0001 for both). The SUVmax was significantly lower in groups A (4.1 +/- 1.9) and B (3.9 +/- 1.4) than in group C (7.1 +/- 4.4) (p = 0.01, p = 0.002, respectively).
Our results indicated that calcification in mLNs related to the ability of I-131 accumulation and less dedifferentiation..
|79.||Shinji Ogawa, Hiroaki Kobayashi, Satoshi Amada, Hideaki Yahata, Kenzo Sonoda, Koichiro Abe, Shingo Baba, Masayuki Sasaki, Tsunehisa Kaku, Norio Wake, Sentinel node detection with (99m)Tc phytate alone is satisfactory for cervical cancer patients undergoing radical hysterectomy and pelvic lymphadenectomy, INTERNATIONAL JOURNAL OF CLINICAL ONCOLOGY, 10.1007/s10147-009-0010-8, 15, 1, 52-58, 15(1):52-8. Epub 2010 Jan 21., 2010.02, If the sentinel-lymph-node (SLN) concept is valid in cervical cancer, most patients could avoid pelvic lymphadenectomy when absence of metastasis is intraoperatively confirmed in the SLN. We assessed feasibility and accuracy of SLN detection using (99m)Tc phytate in patients with cervical cancer.
Eighty-two women with stage Ia-IIb cervical cancer enrolled in this study. All underwent hysterectomy or trachelectomy with accompanying total pelvic lymphadenectomy. On the day before surgery, we injected fluid containing (99m)Tc-labeled phytate subepithelially into four cervical quadrants outside the tumor. Intraoperatively, SLNs were identified as radioactive "hot nodes" by gamma probe. Systematic bilateral pelvic lymphadenectomy was performed after the hot node sampling to evaluate the predictive ability of hot nodes.
A total of 157 lymph nodes were detected as SLNs in 72 of 82 patients. SLN detection rate was 88%. Detection rate was 95% for the subgroups of patients with stage Ia-Ib1 disease and smaller tumor size (a parts per thousand currency sign3 cm in maximal diameter). Lymph node metastasis was found in 15 patients. In 3 of them, no SLNs were detected. In the remaining 12 patients, each ipsilateral SLN contained metastasis when the pelvic lymph nodes contained metastases. Sensitivity was 100%, the false negative rate was 0%, and the negative predictive value of SLN was 100%.
We conclude SLN detection using (99m)Tc-labeled phytate is satisfactory to assess pelvic nodes in patients with early cervical cancer; if validated with other research, it should be incorporated into clinical practice..
|80.||Koichiro Kaneko, Koichiro Abe, Shingo Baba, Takuro Isoda, Hidetake Yabuuchi, Masayuki Sasaki, Masamitsu Hatakenaka, Hiroshi Honda, Detection of Residual Lymph Node Metastases in High-Risk Papillary Thyroid Cancer Patients Receiving Adjuvant I-131 Therapy The Usefulness of F-18 FDG PET/CT, CLINICAL NUCLEAR MEDICINE, 10.1097/RLU.0b013e3181c3b737, 35, 1, 6-11, 35(1): 6-11., 2010.01, Objective: The aims of this retrospective study were to evaluate the incidence of residual lymph node (LN) metastases in high-risk papillary thyroid cancer (PTC) patients receiving adjuvant I-131 therapy, especially in those without I-131 accumulation, and to evaluate the clinical usefulness of F-18 FDG PET/CT to detect those lesions.
Methods: The 37 PTC patients receiving adjuvant I-131 therapy were retrospectively evaluated. We examined the incidence of residual LN metastasis and compared the accumulation of F-18 FDG and I-131 in those lesions, and compared the serum thyroglobulin (Tg) levels between patients with and without residual LN metastases.
Result: A total of 33 lesions were diagnosed as residual LN metastases in 9 patients. FDG accumulated in all of the lesions, but 19 lesions (57.6%) of them had no I-131 accumulation. The SUVmax was significantly higher in lesions without I-131 accumulation than in lesions with I-131 accumulation (6.6 +/- 2.8 vs. 4.2 +/- 1.8; P = 0.007). The serum Tg levels were significantly higher in patients with residual LN metastases than in patients without it (709.9 +/- 1470.8 vs. 25.6 +/- 37.1 ng/mL; P = 0.005). The incidence of residual LN metastasis was significantly higher in patients with a detectable serum Tg level than in patients without it (35.0% vs. 0%, P = 0.03).
Conclusion: These results indicate that the residual LN metastasis was relatively common in high-risk PTC patients receiving adjuvant I-131 therapy whose serum Tg levels remained detectable, and those lesions often had no I-131 accumulation, FDG-PET/CT would be recommended for PTC patients with detectable serum Tg levels to detect residual LN metastases..
|81.||Tatsuya Mitsumoto, Nobuyoshi Ohya, Atsushi Ichimiya, Yuichi Sakaguchi, Aya Kiyota, Koichiro Abe, Junji Morishita, Masayuki Sasaki, Diagnostic performance of Tc-99m HMPAO SPECT for early and late onset Alzheimer's disease: a clinical evaluation of linearization correction, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-009-0266-0, 23, 5, 487-495, 23(5):487-495., 2009.07, This study examined the influence of linearization correction (LC) on brain perfusion single-photon emission computed tomography (SPECT) for the diagnosis of Alzheimer's disease (AD).
The early onset group (< 65 years old) consisted of 10 patients with AD, and the late onset group (a parts per thousand yen65 years old) of 13 patients with AD. Age-matched controls included seven younger and seven older normal volunteers. Tc-99m hexamethyl propyleneamine oxine (HMPAO) SPECT images were reconstructed with or without LC [LC (+) or LC (-)] and a statistical analysis was performed using a three-dimensional stereotactic surface projection (3D-SSP). In addition, a fully automatic diagnostic system was developed, which calculated the proportion of the number of abnormal pixels in the superior and inferior parietal lobule, as well as in the precuneus and posterior cingulate gyrus.
The areas under the receiver-operating characteristic curve (AUCs) of the early onset group for conventional axial SPECT images, SPECT + 3D-SSP images and the fully automatic diagnostic system were 0.71, 0.88, and 0.92 in LC (-) and 0.67, 0.85, and 0.91 in LC (+), respectively. The AUCs of the late onset group were 0.50, 0.61, and 0.79 in LC (-) and 0.49, 0.67, and 0.85 in LC (+), respectively.
LC on Tc-99m HMPAO SPECT did not significantly influence the diagnostic performance for differentiating between AD and normal controls in either early or late onset AD. Further examination with individuals suffering from very mild dementia is, therefore, expected to elucidate the effect of LC on minimally hypoperfused areas..
|82.||Koichiro Abe, Shingo Baba, Koichiro Kaneko, Takuro Isoda, Hidetake Yabuuchi, Masayuki Sasaki, Shuji Sakai, Ichiro Yoshino, Hiroshi Honda, Diagnostic and prognostic values of FDG-PET in patients with non-small cell lung cancer, CLINICAL IMAGING, 10.1016/j.clinimag.2008.06.032, 33, 2, 90-95, 33(2):90-95, 2009, 2009.03, Purpose: The aim of this study was to address the efficacy of 2-[F-18]-Fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) in the staging of non-small cell lung cancer (NSCLC) and in prognostic prediction in patients with NSCLC. Methods: Forty-four patients (26 males, 18 females) were analyzed. Results: Accurate staging was obtained by addition of FDG-PET. Multivariate analysis indicated that the standardized uptake value of the primary tumor was the most significant prognostic factor for disease-free survival (P=.0073). Conclusion: FDG-PET is useful for the diagnosis of NSCLC and for prognostic prediction in patients with NSCLC. (C) 2009 Elsevier Inc. All rights reserved..|
|83.||Tashima Y, Abe K, Matsuo Y, Baba S, Kaneko K, Isoda T, Yabuuchi H, Sasaki M, Honda H., Pul monary tumor thrombotic microangiopathy: FDG-PET/CT findings., Clinical Nuclear Medicine, 34(3):175-177, . 2009, 2009.03.|
|84.||Koichiro Kaneko, Shigeru Fujimoto, Yasushi Okada, Takashi Yoshiura, Kotaro Yasumori, Toru Muranaka, Masayuki Sasaki, Hirofumi Koga, Koichiro Abe, Hirofumi Sawamoto, Hiroshi Honda, SPECT evaluation of cerebral blood flow during arm exercise in patients with subclavian steal, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-007-0054-7, 21, 8, 463-470, 21 (8): 463 – 470, 2007, 2007.10, Objectives: To explore the cerebral hemodynamics in subclavian steal syndrome, we examined the cerebral perfusion of seven patients with subclavian steal (one symptomatic and six asymptomatic) using single-photon emission computed tomography (SPECT) during resting, arm exercise, and acetazolamide-activated conditions.
Methods: The regional CBF (rCBF) was measured with SPECT under all conditions, and region of interest (ROI) analysis was performed using a three-dimensional stereotaxic ROI template (3DSRT). We evaluated the relationship between arm exercise-induced rCBF change and (1) presence of subclavian artery stenosis, (2) vertebral reverse flow severity, (3) presence of vertebro-basilar insufficiency (VBI) symptoms, and (4) cerebrovascular reactivity (CVR) to acetazolamide.
Results: Overall, no arm exercise-induced rCBF reduction was observed on either the affected or the unaffected side, even in patients with severe vertebral reverse flow. One patient with VBI symptoms showed an arm exercise-induced global rCBF reduction in the cerebrum and cerebellum, whereas the other asymptomatic patients did not. The %rCBF changes in segments with severely impaired CVR (-8.6%+/- 10.7%, mean +/- SD) were significantly lower than those in other segments with less impaired CVR (P < 0.01).
Conclusions: Our results suggest that subclavian steal is a benign condition in asymptomatic patients. On the other hand, arm exercise-induced rCBF reduction can occur in the cerebrum and cerebellum in patients with VBI symptoms possibly related to low CVR..
|85.||Koichiro Abe, Masayuki Sasaki, Hirofumi Koga, Koichiro Kaneko, Hirofumi Sawamoto, Hiroshi Yoshikawa, Hiroshi Honda, Clinical role of I-123-IMp SPECT for the differential diagnosis of ocular malignant melanoma: A time-course analysis, NUCLEAR MEDICINE COMMUNICATIONS, 10.1097/MNM.0b013e328194f221, 28, 7, 567-573, 28 (7): 567 – 573, 2007, 2007.07, Objective To evaluate the efficacy of I-123-IMp single photon emission computed tomography (SPECT) for the diagnosis of ocular malignant melanoma (MM).
Methods Thirty-eight patients (18 males, 20 females) clinically suspected of having ocular MM were retrospectively examined in this study. The age of patients ranged from 8 to 81 years (mean 55.6 years). Twelve patients were finally diagnosed as having ocular MM. Orbital SPECT images were taken 15 min, 4 h, 24 h and 48 h after intravenous injection of 111-222 M Bq (3-6 mCi) I-123-IMp. I-123-IMp uptake in the orbital tumor was visually evaluated as - (negative), +/- (equivocal), or + (positive - The uptake index (UI) and increase ratios (IRs) were calculated.
Results For visual evaluation, the accuracy of I-123-IMp for the diagnosis of M M was 73.7% (15 min), 81.6% (4 h), 81.6% (24 h) and 86.8% (48 h). When U I and I R were calculated on both the MM and non-MM groups, the UI and IR of the MM group were significantly higher than those of the non-MM group (P < 0.001). Moreover, the highest sensitivity (100%) and accuracy (94.7%) were obtained 48 h after I-123-IMP administration when the cut-off value of UI was defined as 1.90.
Conclusions This study shows that I-123-IMp SPECT is useful for the diagnosis of ocular M M. The U I values 48 h after the injection were efficient for the differentiation between MM and non-MM lesions..
|86.||Kimiaki Hashiguchi, Takato Morioka, Fumiaki Yoshida, Tadao Kawamura, Yasushi Miyagi, Yasuo Kuwabara, Masayuki Sasaki, Hirofumi Koga, Shinji Nagata, Tomio Sasaki, Thalamic hypometabolism on (18)FDG-positron emission tomography in medial temporal lobe epilepsy, NEUROLOGICAL RESEARCH, 10.1179/174313206X153851, 29, 2, 215-222, 29(2):215-222, 2007, 2007.03, Objectives: Degree of hypometabolism in the thalamus on (18)Fluorodeoxyglucose-positron emission tomography (FDG-PET) was compared with those of medial and lateral temporal lobes in patients with medial temporal lobe epilepsy (mTLE), and its relationship with post-operative seizure outcomes was investigated.
Methods: Twenty-six patients with mTLE who underwent anterior temporal lobectomy were included. Post-operatively, 13 patients became completely seizure-free and 13 showed residual seizure, regardless of frequency (five patients became almost seizure-free, six had rare seizures and two showed significant improvements). Degrees of hypometabolism in bilateral thalamus, ipsilateral medial and lateral temporal lobes were evaluated visually and semi-quantitatively by determining the asymmetry index (AI), a value indicating 100 x (ipsilateral-contralateral)/[1/2x ( ipsilateral + contralateral)] and the region-to-cerebral hemisphere ratio (R/C ratio) being the ratio between averaged counts in each area and those in the cerebral hemisphere of the same side.
Results: Hypometabolism in the medial temporal lobe was visually observed in all patients. Hypometabolism in the lateral temporal lobe was observed in 20 patients and was semiquantitatively more prominent than that of the medial temporal lobe. Pathologically, hippocampal sclerosis and prominent astrogliosis of the lateral temporal lobe were present in all cases. However, while thalamic hypometabolism was visually observed in nine patients (in the ipsilateral side of four cases, contralateral side of three and on both sides of two), no significant thalamic hypometabolism was semi-quantitatively observed. No significant differences in metabolic rate in any area except for the lateral temporal lobe between seizure-free patients and residual seizure patients were seen semi-quantitatively.
Discussion: Data indicated that metabolism in the lateral temporal lobe of patients with mTLE significantly decreased and revealed pathologic glial changes. Thalamic hypometabolism was quite mild and did not correlate with post-operative seizure outcome..
|87.||Abe K, Hayashi K, Sasaki M, Koga H, Kaneko K, Sawamoto H, Himuro K, Honda H., O-(2-[18F]fluoroethyl)-L-tyrosine (18F-FET) uptake in mouse thymoma cells, and its biodistribution in mice and human volunteer., Acta Radiologica, 47 (10); 1042 – 1048, 2006, 2006.12.|
|88.||Kaneko K, Sasaki M, Morioka T, Koga H, Abe K, Sawamoto H, Ohya N, Yoshiura T, Mihara F, Honda H., Pre-surgical identification of epileptogenic areas in temporal lobe epilepsy by 123I-iomazenil SPECT: A comparison with IMP SPECT and FDG PET., Nuclear Medicine Communications, 27 (11): 893 – 899, 2006, 2006.11.|
|89.||Koichiro Kaneko, Masayuki Sasaki, Takato Morioka, Hirofumi Koga, Koichiro Abe, Hirofumi Sawamoto, Nobuyoshi Ohya, Takashi Yoshiura, Futoshi Mihara, Hiroshi Honda, Pre-surgical identification of epileptogenic areas in temporal lobe epilepsy by I-123-iomazenil SPECT: A comparison with IMP SPECT and FDG PET, NUCLEAR MEDICINE COMMUNICATIONS, 10.1097/01.mnm.0000243380.79872.32, 27, 11, 893-899, 2006.11, Objectives The aim of this study was to evaluate the usefulness of I-123-iomazenil (IMZ) single photon emission computed tomography (SPECT) for the pre-surgical identification of epileptogenic areas in patients with temporal lobe epilepsy and to compare the results with those of I-123-IMP SPECT and (l18)Fluorodeoxyglucose positron emission tomography (FDG PET).
Methods We examined seven patients with medically refractory temporal lobe epilepsy (five men and two women; mean age, 28 years) with no remarkable findings on magnetic resonance imaging. Before surgery, IMZ SPECT, I M P SPECT and FDG PET were all performed in the interictal state. Then, visual assessment and region-of-interest (ROI) analysis were performed on each image. Final definitions of the epileptogenic areas were made by electrocorticography and histopathology.
Results By IMZ SPECT, a decreased IMZ uptake in the ipsilateral temporal lobe was found in all patients, while a similar decrease in the contralateral temporal lobe was also found in one patient. In comparison to IMP SPECT, the extent of the abnormal area on IMZ SPECT was equal to that on IMP SPECT in one patient while it was more restricted to the epileptogenic area in five patients. In comparison to FDG PET, the extent of the abnormal area on IMZ SPECT was equal to that on FDG PET in three patients while it was more restricted in the epileptogenic area in four patients. In ROI analysis, decreases of IMZ, IMP and FDG uptake were observed in the epileptogenic area, although they were not statistically significant.
Conclusions IMZ SPECT was considered to be useful for pre-surgical determination of the epileptogenic areas in temporal lobe epilepsy with no remarkable MRI findings, and it was also found to be superior to IMP SPECT and FDG PET for this purpose..
|90.||Horikawa H, Monji A, Sasaki M, Maekawa T, Onitsuka T, Nitazaka Y, Hirano Y, Hirano S, Hashioka S, Kato T, Yoshida I, Kanba S, Different SPECT findings before and after Capgrs’ syndrome in interictal psychosis., Epilepsy Behav, 9 (1): 189 – 192, 2006, 2006.08.|
|91.||K Abe, M Sasaki, Y Kuwabara, H Koga, S Baba, K Hayashi, N Takahashi, H Honda, Comparison of (18)FDG-PET with Tc-99m-HMDP scintigraphy for the detection of bone metastases in patients with breast cancer, ANNALS OF NUCLEAR MEDICINE, 19, 7, 573-579, 19 (7); 573 – 579, 2005.10, Objective: Bone is one of the most common sites of metastasis in breast cancer patients. Although bone scintigraphy is widely used to detect metastatic breast cancer, the usefulness of (18)FDG-PET for detecting bone metastasis has not been clearly evaluated. The purpose of this study was to compare the diagnostic accuracy of (18)FDG-PET with bone scintigraphy in detecting bone metastasis in breast cancer patients. Methods: Forty-four women aged 35 to 81 years (mean, 56 years) with breast cancer were examined in this study. Both (18)FDG-PET and bone scintigraphy were performed for each patient with 0-69 day intervals (mean, 11.5 days). The results of each image interpretation were compared retrospectively. Whole-body bones were classified into 9 anatomical regions. Metastases were confirmed at 45/187 regions in 14 patients by bone biopsy or clinical follow-up including other imaging techniques for a period of at least 6 months afterwards. Results: On a region basis, the sensitivity, specificity, and accuracy of (18)FDG-PET were 84%, 99% and 95%, respectively. Although these results were comparable to those of bone scintigraphy, the combination of 18FDG-PET and bone scintigraphy improved the sensitivity (98%) and accuracy (97%) of detection. False negative lesions of bone scintigraphy were mostly bone marrow metastases and those of (18)FDG-PET were mostly osteoblastic metastases. (18)FDG-PET was superior to bone scintigraphy in the detection of osteolytic lesions (92% vs. 73%), but inferior in the detection of osteoblastic lesions (74% vs. 95%). Conclusions: This study shows that (18)FDG-PET tends to be superior to bone scintigraphy in the detection of osteolytic lesions, but inferior in the detection of osteoblastic lesions. (18)FDG-PET should play a complementary role in detecting bone metastasis with bone scintigraphy..|
|92.||Nakagawa M, Kuwabara Y, Taniwaki T, Sasaki M, Koga H, Kaneko K, Hayashi K, Kira J, Honda H., PET evaluation of the relationship between D2 receptor binding and glucose metabolism in patients with parkinsonism, Annals of Nuclear Medicine, 10.1007/BF02984618, 19, 4, 267-275, 19 (4); 267 – 275, 2005, 2005.06.|
|93.||Abe K, Sasaki M, Kuwabara Y, Koga H, Baba S, Kaneko K, Hayashi K, Honda H, Shioyama Y, Tajiri T, Suita S., Extraosseous accumulation of 99mTc-HMDP to radiation nephropathy, mimicking recurrent neuroblastoma, Annals of Nuclear Medicine, 10.1007/BF02986333, 19, 1, 35-40, 19 (1): 35 - 40, 2005, 2005.02.|
|94.||K Abe, M Sasaki, Y Kuwabara, H Koga, S Baba, K Kaneko, K Hayashi, Y Shioyama, T Tajiri, S Suita, H Honda, Extraosseous accumulation of Tc-99m-HMDP to radiation nephropathy, mimicking recurrent neuroblastoma, ANNALS OF NUCLEAR MEDICINE, 19, 1, 35-40, 2005.02, Objective: The aim of this study is to clarify the period of extraosseous accumulation of Tc-99m-hydroxymethylenediphosphonate (HMDP) to radiation nephropathy mimicking recurrent or remnant neuroblastoma in the pararenal region. Methods: We reviewed five neuroblastoma and one ganglioneuroblastoma patients (2 boys and 4 girls aged 1-9 years) who underwent Tc-99m-HMDP bone scintigraphies periodically before and after radiation therapy. Results: Increased renal uptake coincident with the radiation port appeared in 5 of 6 patients from 0 to 3 months (mean 1.7 months), and persisted up to 7 months after the completion of radiotherapy. Renal uptake of Tc-99m-HMDP was gradually decreased, and eventually became accumulation defects in 5 of 6 patients from 6 to 17 months (mean 8.9 months) after radiotherapy. Conclusion: When extraosseous accumulation is found after radiation therapy in neuroblastoma patients, radiation nephropathy would be a candidate in the differential diagnosis besides recurrent or remnant tumor..|
|95.||Kaneko K, Kuwabara Y, Sasaki M, Koga H, Abe K, Baba S, Hayashi K, Honda H, Validation of quantitative accuracy of the post-injection transmission-based and transmissionless attenuation correction techniques in neurological FDG-PET, Nuclear Medicine Communicatoins, 10.1097/00006231-200411000-00005, 25, 11, 1095-1102, 25: 1095 – 1102, 2004, 2004.10.|
|96.||Kaneko K, Kuwabara Y, Sasaki M, Ogomori K, Ichimiya A, Koga H, Nakagawa M, Hayashi K, Honda H, Posterior cingulate hypoperfusion in Alzheimer's disease, senile dementia of Alzheimer type, and other dementias evaluated by three-dimensional stereotactic surface projections using Tc-99m HMPAO SPECT., Clinical Nuclear Medicine, 10.1097/01.rlu.0000127091.43180.92, 29, 6, 362-366, 29(6):362 – 366, 2004, 2004.06.|
|97.||Kaneko K, Kuwabara Y, Mihara F, Yoshiura T, Nakagawa M, Tanaka A, Sasaki M, Koga H, Hayashi K, Honda H, Validation of the CBF, CBV, and MTT values by perfusion MRI in chronic occlusive cerebrovascular disease: a comparison with 15O-PET, Acad Radiol, 10.1016/S1076-6332(03)00722-0, 11, 5, 489-497, 11 (5): 489 – 497, 2004.05.|
|98.||Koga H, Sasaki M, Kuwabara Y, Nakagawa M, Kaneko K, Hayashi K, Chen T, Honda H, Lesion detectability of a gamma camera based coincidence system with FDG in patients with malignant tumors: a comparison with dedicated positron emission tomography., Ann Nucl Med, 10.1007/BF02985103, 18, 2, 131-136, 18 (2): 131 - 136, 2004.04.|
|99.||Koga H, Sasaki M, Kuwabara Y, Hiraka K, Nakagawa M, Abe K, Kaneko K, Hayashi K, Honda H, An analysis of physiological uptake pattern in the stomach., Ann Nucl Med, 17 (8): 733 - 785, 2003.12.|
|100.||Sasaki M, Sugio K, Kuwabara Y, Koga H, Nakagawa M, Chen T, Kaneko K, Hayashi K, Shioyama Y, Sakai S, Honda H, Alterations of tumor suppressor genes (Rb, p16, p27 and p53) and increased FDG uptake in lung cancer, Annals of Nuclear Medicine, 10.1007/BF02990021, 17, 3, 189-196, 17 (3): 189 - 196, 2003.05.|
|101.||Mihara F, Kuwabara Y, Yoshiura T, Tanaka A, Kaneko K, Sasaki M, Honda H, Matsushima T, Semi-quantitative CBF and CBF ratios obtained using perfusion-weighted MR imaging, Neuroreport, 10.1097/01.wnr.0000065511.53896.7c, 14, 5, 725-727, 14 (5): 725 - 727, 2003.05.|
|102.||M Sasaki, K Sugio, Y Kuwabara, H Koga, M Nakagawa, T Chen, K Kaneko, K Hayashi, Y Shio-Yama, S Sakai, H Honda, Alterations of tumor suppressor genes (Rb, p16, p27 and p53) and an increased FDG uptake in lung cancer, ANNALS OF NUCLEAR MEDICINE, 17, 3, 189-196, 2003.05, Objective: The FDG uptake in lung cancer is considered to reflect the degree of malignancy, while alterations of some tumor suppressor genes are considered to be related to the malignant biological behavior of tumors. The aim of this study is to examine the relationship between FDG-PET and alterations in the tumor suppression genes of lung cancer. Methods: We examined 28 patients with primary lung cancer who underwent FDG-PET before surgery consisting of 17 patients with adenocarcinoma, 10 with squamous cell carcinoma and I with large cell carcinoma. The FDG-PET findings were evaluated based on the standardized uptake value (SUV). Alterations in the tumor suppressor genes, Rb, p16, p27 and p53, were evaluated immunohistochemically. Results: The FDG uptake in lung cancer with alteration in each tumor suppressor gene tended to be higher than in those genes without alterations, although the differences were not significant. In 15 tumors with alterations in either tumor suppressor genes, the FDG uptake was 6.83 +/- 3.21. On the other hand, the mean FDG uptake was 1.95 in 2 tumors without alterations in any genes. The difference in the FDG uptake between the 2 groups was statistically significant (p < 0.001). Conclusions: In conclusion, the presence of abnormalities in the tumor suppressor genes, which results in an accelerated cell proliferation, is thus considered to increase the FDG uptake in lung cancer..|
|103.||Mihara F, Kuwabara Y, Tanaka A, Yoshiura T, Sasaki M, Yoshida T, Masuda K, Matsushima T., Reliability of mean transit time obtained using perfusion-weighted MR imaging; comparison with positron emission tomography, Megnetic Resonance Imaging, 10.1016/S0730-725X(02)00629-X, 21, 1, 33-39, 21 (1): 33 – 39, 2003.01.|
|104.||Yoshiura T, Mihara F, Kuwabara Y, Ogomori K, Kaneko K, Tanaka A, Sasaki M, Nakagawa M, Koga H, Yamanaka T, Masuda K., MR Relative Cerebral Blood Flow Mapping of Alzheimer’s disease: Correlation with Tc-99m HMPAO SPECT, Acad Radiol, 10.1016/S1076-6332(03)80665-7, 9, 12, 1383-1387, 9 (12): 1383 – 1387, 2002.12.|
|105.||Taniwaki T, Nakagawa M, Yamada T, Yoshida T, Ohyagi Y, Sasaki M, Kuwabara Y, Tobimatsu S, Kira J, Cerebral metabolic changes in early multiple system atrophy: a PET study, J Neurol Sc, 10.1016/S0022-510X(02)00151-X, 200, 1-2, 79-84, 200 (1-2): 79 – 84, 2002.08.|
|106.||M Sasaki, Y Kuwabara, H Koga, M Nakagawa, T Chen, K Kaneko, K Hayashi, K Nakamura, K Masuda, Clinical impact of whole body FDG-PET on the staging and therapeutic decision making for malignant lymphoma, ANNALS OF NUCLEAR MEDICINE, 10.1007/BF02988618, 16, 5, 337-345, 16 (5): 337 - 345, 2002.07, Objectives: The aim of this study is to evaluate the clinical impact of whole-body FDG-PET for the pre-therapeutic evaluation of malignant lymphoma and compared to that of Ga-67-scintigraphy when added to non-RI examinations. Methods: We examined 46 patients with malignant lymphoma including 42 newly diagnosed cases and 4 relapsed cases. Whole-body FDG-PET was started 63 minutes after the administration of FDG with ECAT EXACT HR+. The clinical stage of each patient was determined based on the results of a non-RI examination (consisting of physical examination, CT, gastrointestinal studies and bone marrow aspiration), Ga-67 planar images and FDG-PET. Discrepant findings were verified based on the response to treatment and the findings of a follow-up examination more than 6 months after treatment. Finally, 152 nodal regions and 19 extranodal tissues were found to be involved by disease. Results: In the 152 nodal lesions, FDG-PET detected 54 nodal lesions in addition to 98 lesions detected by non-RI examinations, whereas Ga-67-scintigraphy detected 14 additional lesions. The sensitivity of non-RI, non-RI + Ga-67 and non-RI + FDG was 64.5%, 73.7% and 100.0%, respectively. In 19 extranodal lesions, FDG-PET detected 5 extranodal lesions in addition to 13 lesions detected by non-RI examinations, whereas Ga-67-scintigraphy detected I additional lesion. The sensitivity of non-RI, non-RI + 67Ga and non-RI + FDG was 68.4%,73.7% and 94.7%, respectively. When combining the FDG-PET findings with the non-RI findings, the improvement of the detectability was much higher than that when 67Ga findings were combined to the non-RI findings. For the staging of lymphoma, the non-RI and non-RI + 67Ga findings accurately diagnosed 76.1% and 80.4%, respectively, whereas the non-RI + FDG findings accurately diagnosed 82.6%. Finally, FDG-PET resulted in changes in the clinical management of 8 patients (17.4%). Conclusions: FDG-PET offers more information in addition to the findings of conventional diagnostic methods than 67Ga-scintigraphy in order to accurately detect malignant lymphoma. FDG-PET can therefore play an important role in therapeutic decision making on lymphoma..|
|107.||Nakagawa M, Kuwabara Y, Sasaki M, Koga H, Chen T, Kaneko K, Hayashi K, Morioka T, Masuda K., 11C-methionine uptake in cerebrovascular disease: A comparison with 18F-FDG PET and 99mTc-HMPAO SPECT, Annals of Nuclear Medicine, 16 (3): 207 - 211, 2002.05.|
|108.||Chen T, Kuwabara Y, Tsutsui H, Sasaki M, Nakagawa M, Koga H, Kaneko K, Komori K, Masuda K, The usefulness of dipyridamole thallium-201 single photon emission tomography for predicting perioperative cardiac events in patients undergoing non-cardiac vascular surgery, Annals of Nuclear Medicine, 10.1007/BF02995291, 16, 1, 45-53, 16 (1): 45 - 53, 2002.02.|
|109.||Kuwabara Y, Sasaki M, Hirakata H, Koga H, Nakagawa M, Chen T, Kaneko K, Masuda K, Fujishima M, Cerebral blood flow and vasodilatory capacity in anemia secondary to chronic renal failure, Kidney International, 10.1046/j.1523-1755.2002.00142.x, 61, 2, 564-569, 61 (2): 564 - 569, 2002.02.|
|110.||Ishida M, Kitamura K, Kinoshita J, Sasaki M, Kuwahara H, Sugimachi K, Detection of micrometastasis in the sentinel lymph nodes in breast cancer, Surgery, 10.1067/msy.2002.119579, 131, 1, S211-S216, 131 (1 Suppl): S211 - S216, 2002.01.|
|111.||M Sasaki, Y Kuwabara, T Yoshida, M Nakagawa, H Koga, K Hayashi, K Kaneko, T Chen, Y Ichiya, K Masuda, Comparison of MET-PET and FDG-PET for differentiation between benign lesions and malignant tumors of the lung, ANNALS OF NUCLEAR MEDICINE, 10.1007/BF02988346, 15, 5, 425-431, Vol.15,No.5,pp.425 - 431, 2001.10, Objective: We retrospectively assessed and compared the usefulness of I I C-methionine (MET)PET with that of F-18-FDG-PET for the differentiation between benign lesions and malignant tumors of the lung. Methods: We examined 101 patients with a suspected lung tumor including 79 patients with primary lung cancer and 22 patients with benign lesions. One hundred and forty PET studies (46 studies with MET-PET and 94 studies with FDG-PET) were performed. Both MET-PET and FDG-PET were performed on 39 patients. The MET-PET was performed 15 minutes after the administration of 67-740 MBq of MET, and FDG-PET 45 minutes after the administration of 30-437 MBq of FDG. The results were then evaluated by the standardized uptake value (SUV). Results: The MET uptake in lung cancer was 3.69 +/-1.22 (n = 37) which was significantly higher than that in benign lesions 1.81 +/-1.04 (n = 9) (p < 0.001). The sensitivity, specificity and accuracy of MET-PET were 83.8%, 88.9% and 84.8%, respectively, when 2.66 of SUV was used as the cutoff value. The FDG uptake in lung cancer was 5.94 +/-2.89 (n = 75) and was also significantly larger than that in benign lesions 2.46 +/-1.01 (n = 19) (p < 0.001). The sensitivity, specificity and accuracy of FDG-PET were 81.3%, 78.9% and 80.9%, respectively (cutoff = 3.20). The MET uptake in the lesions correlated significantly with FDG uptake (r = 0.71, p < 0.001). According to an ROC analysis, the area under the curve for MET-PET (area = 0.833) was higher than that for FDG-PET (area = 0.828), but the difference was not statistically significant. Furthermore, the combined use of MET-PET and FDG-PET did not improve the diagnostic ability. Conclusions: In conclusion, both MET-PET and FDG-PET were considered to be equally useful for the differential diagnosis of lung tumors. Furthermore, MET uptake in lung lesions was found to correlate significantly with FDG uptake..|
|112.||Sasaki M, Fukumura T, Kuwabara Y, Yoshida T, Nakagawa M, Ichiya Y, Masuda K, Biodistribution and breast tumor uptake of 16α-[18F]-fluoro-17β-estradiol in rat, Ann Nucl Med, 10.1007/BF02988592, 14, 2, 127-130, Vol.14,No.2,pp.127 - 130, 2000.02.|
|113.||Sasaki M, Kuwabara, Y, Ichiya, Y, Yoshida, T, Nakagawa, M, Soeda, H, Sugio, K, Maehara, Y, Masuda, Prediction of the chemosensitivity of lung cancer by 99mTc-hexakis-2-methoxyisobutyl isonitrile SPECT, J Nucl Med, 40, 11, 1778-1783, Vol.40,No.11,pp.1778 - 1783, 1999.11.|
|114.||M Sasaki, Y Kuwabara, Y Ichiya, T Yoshida, M Nakagawa, H Soeda, K Sugio, Y Maehara, K Masuda, Prediction of the chemosensitivity of lung cancer by Tc-99m-hexakis-2-methoxyisobutyl isonitrile SPECT, JOURNAL OF NUCLEAR MEDICINE, 40, 11, 1778-1783, 1999.11, Tc-99m-hexakis-2-methoxyisobutyl isonitrile (MIBI) has been reported to accumulate in various tumors and to be a transport substrate for P-glycoprotein (Pgp). The aim of this study was to evaluate the usefulness of Tc-99m-MIBI SPECT for in vivo assessment of lung cancer chemosensitivity. Also examined was the relationship between 99mTc-MIBI uptake and Pgp expression. Methods: Ten lung cancer patients who had undergone surgery were examined. Before surgery, 99mTc-MIBI SPECT was performed 15 and 120 min after injection, and the early uptake (L/Ne), delayed uptake (L/Nd) and washout rate (L/Nwr) of 99mTc-MIBI were calculated by the count ratio of lesion to contralateral normal lung tissue. The results were then compared with chemosensitivity determined by the succinate dehydrogenase inhibition test using six antitumor drugs (doxorubicin, mitomycin C [MMC], vindesine, etoposide [VP-16], cyclophosphamide and cisplatin). Pgp expression was determined by immunohistochemical staining, Results: Sensitivity to MMC correlated significantly with L/Ne (P < 0.01) and L/Nwr (P < 0.05), Sensitivity to VP-16 correlated weakly and insignificantly with L/Nwr. L/Nd showed no correlation with sensitivity to any drug. Neither L/Ne, L/Nd nor L/Nwr was significantly different between the Pgp-positive group (n = 2) and the Pgp-negative group (n = 8). Conclusion: The results suggest that Tc-99m-MIBI SPECT, a noninvasive in vivo examination, can predict the chemosensitivity of lung cancer to MMC and VP-16 independently of Pgp expression..|
|115.||M Sasaki, Y Kuwabara, Y Ichiya, Y Akashi, T Yoshida, M Nakagawa, S Murayama, K Masuda, Differential diagnosis of thymic tumors using a combination of C-11-methionine PET and FDG PET, JOURNAL OF NUCLEAR MEDICINE, 40, 10, 1595-1601, 1999.10, We assessed the usefulness of PET studies in making a differential diagnosis of thymic tumors by using C-11-methionine (MET) and F-18-fluorodeoxyglucose (FDG). Methods: We examined 31 patients with thymic tumors, including 14 patients with thymic cancer, 9 with invasive thymoma, 5 with noninvasive thymoma and 3 with thymic cysts. The histological diagnosis was confirmed by either surgery or biopsy. MET PET and FDG PET were performed in 28 and 29 patients, respectively. Both the MET and FDG uptakes were evaluated by the standardized uptake value (SUV). Results: MET uptake was not substantially different among thymic cancer (4.8 +/- 1.4), invasive thymoma (4.3 +/- 1.1) and noninvasive thymoma (4.5 +/- 1.2), but MET uptake in thymic cysts (0.9 +/- 0.1) was lower than that in the other three tumors (P < 0.01). The FDG uptake in thymic cancer (7.2 +/- 2.9) was higher than that in invasive thymoma (3.8 +/- 1.3), noninvasive thymoma (3.0 +/- 1.0) and thymic cysts (0.9) (P < 0.01). MET uptake in thymic tumors correlated with the FDG uptake (r = 0.65), whereas MET uptake in thymic cancer was tower than FDG uptake (FDG/MET ratio = 1.52 +/- 0.52) but was higher than FDG uptake in both invasive and noninvasive thymoma (FDG/MET ratio = 0.86 +/- 0.33), To differentiate thymic cancer from thymoma, a receiver operating characteristic (ROC) analysis was performed. The area under the curve of FDG PET was 0.90, whereas the FDG/MET ratio was 0.87. Conclusion: The MET PET, FDG PET and the FDG/MET ratios were unable to differentiate benign thymic tumors from malignant ones, although FDG PET was considered to be useful in the differential diagnosis between thymic cancer and thymoma. Although the difference in the uptake ratio between FDG and MET suggests a different origin of the tumors, the FDG/MET ratio is not considered to be useful as a complementary method for the differential diagnosis of thymic tumors..|
|116.||M Sasaki, Y Kuwabara, T Yoshida, M Nakagawa, T Fukumura, F Mihara, T Morioka, M Fukui, K Masuda, A comparative study of thallium-201 SPET, carbon-11 methionine PET and fluorine-18 fluorodeoxyglucose PET for the differentiation of astrocytic tumours, EUROPEAN JOURNAL OF NUCLEAR MEDICINE, 10.1007/s002590050294, 25, 9, 1261-1269, Vol.25,No.9,pp.1262 - 1269, 1998.09, Thallium-201, carbon-ii methionine (MET) and fluorine-18 fluorodeoxyglucose (FDG) have all been used to assess brain tumours. The aim of this study was to determine which of these tracers are of use for evaluating the histological grade and the extent of astrocytoma. Tl-201 single-photon emission tomography (SPET), MET positron emission tomography (PET) and FDG PET were all performed in 23 patients (13 men, 10 women) with newly diagnosed astrocytic rumours [seven with astrocytoma (grade II), ten with anaplastic astrocytoma (grade III) and six with glioblastoma (grade IV)]. The Tl-201 uptake of the rumours was evaluated by a lesion-to-normal region count ratio. Both MET and FDG uptake of the tumours was evaluated by a semiquantitative analysis using the standardized uptake value. Tl-201 uptake was found to increase in rank order with histological grade and was significantly different among the three groups (grade II: 1.51+/-0.36; grade III: 2.58+/-1.50; grade IV: 7.65+/-3.84). MET uptake in grade II (1.49+/-0.44) was also significantly lower than that in both grade III (3.29+/-1.44) and grade IV (3.20+/-0.92). FDG uptake was not significantly different among the three groups (grade II: 2.90+/-0.45; grade III: 3.86+/-1.56; grade IV: 3.57+/-0.83). No significant correlation was observed between Tl-201 uptake and either MET uptake or FDG uptake. In most patients, the extent of the increased MET uptake was the largest while that of the increased FDG uptake was the smallest. In patients with positive Tl-201 uptake, the extent of the Tl-201 uptake was equal to or smaller than that of gadolinium enhancement. For evaluation of histological grade of astrocytic tumours. Tl-201 is therefore considered to be useful though the Tl-201 uptake in some grade III astrocytomas was not different from that in grade II astrocytomas. MET was found to be highly useful for detecting astrocytomas, for differentiating between benign and malignant astrocytomas, and for evaluating the extent of astrocytomas; however, it was not sufficiently useful permit evaluation of the histological grade. FDG was not found to be useful either for evaluating the histological grade or for differentiating: between benign and malignant astrocytomas..|
|117.||M Sasaki, Y Kuwabara, T Yoshida, T Fukumura, T Morioka, S Nishio, M Fukui, K Masuda, Carbon-11-methionine PET in focal cortical dysplasia: A comparison with fluorine-18-FDG PET and technetium-99m-ECD SPECT, JOURNAL OF NUCLEAR MEDICINE, 39, 6, 974-977, Vol.39,No.6,pp.974 - 977, 1998.06, Focal cortical dysplasia is one of the known neuronal migration disorders and has recently been recognized as a cause of intractable epilepsy. in this study, we assessed the (11)C-methionine (MET) uptake in focal cortical dysplasia by PET, and then compared the results with that of (18)F-fluoro-2-deoxy-D-glucose (FDG) PET and (99m)Tc-ethyl cysteinate dimer (ECD) SPECT. Methods: Four patients (3 men, 1 woman; age range 16-68 yr) were examined by PET and SPECT for a presurgical examination of medically intractable seizures. In all 4 patients, (11)C-MET PET was performed for 15 min, started 15 min after the administration of 511-662 MBq MET. In 3 of 4 patients, FDG PET was performed for 15 min, and started 20 min after the administration of 185-370 MBq FDG. In all 4 patients, the cerebral blood flow was also evaluated by (99m)Tc-ECD SPECT for 15 min after the administration of 600 MBq ECD. Results: In MET PET, all 4 lesions were visually recognized to have high MET uptake areas. The MET uptake of the lesions was 1.44 +/- 0.30 for the standardized uptake value (SUV) (ranging from 0.99-1.61). In FDG PET, 2 lesions were demonstrated to have low uptake areas (3.82 in SUV) while I had an ictal high uptake (4.74 in SUV). In ECD SPECT, 1 lesion demonstrated hypoperfusion and I ictal hyperperfusion while 2 showed no abnormalities. All 4 patients underwent a cortical resection and the microscopic examinations were consistent with those of focal cortical dysplasia but no evidence of a tumor was found. Conclusion: MET PET is useful for identifying focal cortical dysplasia as a high uptake area..|
|118.||M Sasaki, Y Ichiya, Y Kuwabara, T Yoshida, T Fukumura, K Masuda, Benzodiazepine receptors in chronic cerebrovascular disease: Comparison with blood flow and metabolism, JOURNAL OF NUCLEAR MEDICINE, 38, 11, 1693-1698, 1997.11, The brain benzodiazepine (BZD) receptor distribution in patients with chronic cerebrovascular disease was assessed with I-123-iomazenil (IMZ) SPECT, and the findings were compared with the data for the cerebral blood flow (CBF) and cerebral metabolism. Methods: We examined nine patients with chronic cerebrovascular diseases, six patients with cerebral infarction and three with moyamoya disease. Iodine-123-IMZ SPECT images were obtained for 15 min, 3 hr after the administration of 167 or 222 MBq I-123-IMZ. In seven patients, the CBF and oxygen metabolism were measured by the O-15 steady-state method. In two patients, the CBF and glucose metabolism were measured by Tc-99m-HMPAO SPECT and F-18-fluoro-2-deoxy-D-glucose-PET, respectively. The brain was initially classified into 18 regions, and abnormalities in the BZD receptor distribution, CBF and cerebral metabolism were visually evaluated. The count ratio of lesion-to-contralateral normal region (L-to-C ratio) was then used for comparison. Results: In the core of the infarct, the I-123-IMZ uptake decreased (L-to-C ratios of the blood flow 0.42 +/- 0.26; metabolism 0.45 +/- 0.24; and I-123-IMZ uptake 0.46 +/- 0.14). In the peri-infarct region, the I-123-IMZ uptake slightly decreased (L-to-C ratios of 0.81, 0.82 and 0.89, respectively). In the region of misery perfusion, the I-123-IMZ uptake was preserved (L-to-C ratios of 0.73, 1.07 and 1.02, respectively). In the remote deafferentated areas in the ipsilateral cerebrum, the I-123-IMZ uptake was preserved (L-to-C ratios of 0.76 +/- 0.10, 0.75 +/- 0.04 and 0.98 +/- 0.05, respectively). In the remote areas in the contralateral cerebellum, the I-123-IMZ uptake was preserved (L-to-C ratios of 0.84 +/- 0.08, 0.85 +/- 0.04 and 0.94 +/- 0.05, respectively). Conclusion: The BZD receptor distribution, as measured by I-123-IMZ SPECT, is not considered to reflect neuronal function, but it may reflect neuronal cell viability. Iodine-123-IMZ SPECT may, therefore, hold promise as a potential probe for neuronal damage..|
|119.||M Sasaki, Y Ichiya, Y Kuwabara, Y Akashi, T Yoshida, T Fukumura, K Masuda, An evaluation of FDG-PET in the detection and differentiation of thyroid tumours, NUCLEAR MEDICINE COMMUNICATIONS, 18, 10, 957-963, 1997.10, We evaluated the usefulness of FDG-PET for the detection of thyroid tumours and the differentiation between benign and malignant tumours. The subjects consisted of 5 normal volunteers and 22 patients, including 3 with follicular adenoma, 16 with papillary carcinoma and 3 with follicular carcinoma. The results were then evaluated both visually and semi-quantitatively using the standardized uptake value (SUV). All 22 tumours were seen as areas of high FDG uptake. FDG uptake in the normal thyroid gland, follicular adenoma, papillary carcinoma and follicular carcinoma was 1.0 +/- 0.2, 2.1 +/- 0.4, 4.7 +/- 3.2 and 4.6 +/- 2.9, respectively. Significant differences were observed between papillary carcinoma and both follicular adenoma (P < 0.05) and the normal thyroid gland (P < 0.001), and between follicular adenoma and the normal thyroid gland (P < 0.001). For the diagnosis of carcinoma, 58% sensitivity, 100% specificity and 73% accuracy were obtained when the highest FDG uptake value in adenoma was taken as the threshold. Our results thus indicate that high FDG uptake in a thyroid tumour suggests malignancy even though low levels of FDG uptake cannot completely rule out malignancy..|
|120.||M Sasaki, Y Ichiya, Y Kuwabara, Y Akashi, T Yoshida, T Fukumura, S Murayama, T Ishida, K Sugio, K Masuda, The usefulness of FDG positron emission tomography for the detection of mediastinal lymph node metastases in patients with non-small cell lung cancer: A comparative study with X-ray computed tomography, EUROPEAN JOURNAL OF NUCLEAR MEDICINE, 10.1007/BF00843701, 23, 7, 741-747, 1996.07, We evaluated the usefulness of fluorine-18-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) in the detection of mediastinal lymph node metastases in patients with non-small cell lung cancer and then compared the findings with the results of X-ray CT by region based on the histological diagnoses. We examined 29 patients with non-small cell lung cancer. One hundred and thirty-two mediastinal lymph nodes were surgically removed and the histological diagnoses were confirmed, FDG PET images, including 146 mediastinal regions, were visually analysed and the mediastinal lymph nodes were scored as positive when the FDG uptake was higher than that in the other mediastinal structures, On the X-ray CT scans, any mediastinal lymph nodes with a diameter of 10 mm or larger were scored as positive. All three examinations were successfully performed on 71 regions. For FDG PET, we found a sensitivity of 76%, a specificity of 98% and an accuracy of 93%. On the other hand, for X-ray CT a sensitivity of 65%, a specificity of 87% and an accuracy of 82% were observed, A significant difference was observed in respect of both specificity and accuracy (P<0.05). Based on the above findings, FDG PET is suggested to be superior to X-ray CT when used for the detection of mediastinal lymph node metastases in patients with non-small cell lung cancer..|
|121.||M Sasaki, Y Ichiya, Y Kuwabara, T Yoshida, T Inoue, T Morioka, K Hisada, M Fukui, K Masuda, Hyperperfusion and hypermetabolism in brain radiation necrosis with epileptic activity, JOURNAL OF NUCLEAR MEDICINE, 37, 7, 1174-1176, 1996.07, We report a case of high uptake of C-11-methionine (MET), F-18-FDG (FDG) and Tl-201-CI (Tl) in brain radiation necrosis. Twenty-one years previously, the patient had undergone surgery and radiation therapy consisting of 60-Gy for ependymoma in the anterior horn of the right lateral ventricle. The clinical features consisting of frequent seizures of the left face and arm suddenly appeared 2 wk before admission. MRI depicted a T1- and T2-prolonged lesion in the right frontal lobe. Abnormally high uptake in this area demonstrated by MET-PET, FDG-PET, Tl-SPECT or HMPAO-SPECT suggested the presence of a recurrent tumor. A craniotomy was then performed and an intraoperative electrocorticogram showed continuous epileptic spikes in the lesion. The epileptic foci were resected and the histological features of the lesion were consistent with radiation necrosis. After surgery, the seizures disappeared and the postoperative examinations with MET-PET, FDG-PET, Tl-SPECT and HMPAO-SPECT no longer showed abnormally high uptake. Hypermetabolism and hyperperfusion related to epileptic fits are therefore thought to result in high uptake of MET, FDG and Tl in radiation necrosis..|
|122.||M SASAKI, HW MULLERGARTNER, LEVER, JR, HT RAVERT, RF DANNALS, TR GUILARTE, HN WAGNER, ASSESSMENT OF BRAIN MUSCARINIC ACETYLCHOLINERGIC RECEPTORS IN LIVING MICE USING A SIMPLE PROBE, [I-125] 4-IODODEXETIMIDE AND [I-125] 4-IODOLEVETIMIDE, NEUROPHARMACOLOGY, 10.1016/0028-3908(93)90043-3, 32, 12, 1441-1443, 1993.12, This study describes assessment of brain muscarinic acetylcholinergic receptors in living mice using a single-crystal radiation detection system, the high-affinity antagonist [I-125]-4-iododexetimide, and the inactive enantiomer [I-125]-4-iodolevetimide. Kinetics of radioligand binding, as well as perturbation by atropine displacement, can be determined using this simple probe technique..|
|123.||M SASAKI, Y ICHIYA, Y KUWABARA, M OTSUKA, T FUKUMURA, Y KAWAI, H KOGA, K MASUDA, FLUORINE-18-FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY IN TECHNETIUM-99M-HYDROXYMETHYLENEDIPHOSPHATE NEGATIVE BONE-TUMORS, JOURNAL OF NUCLEAR MEDICINE, 34, 2, 288-290, 1993.02, We have encountered two cases of bone tumors with high F-18-fluorodeoxyglucose (FDG) uptake and negative Tc-99m-HMDP bone scintigraphy, including a patient with myeloma and a patient with a metastatic bone tumor from esophageal cancer. Bone scintigraphy with a Tc-99m-phosphate complex reflects osteoblastic activity in the bone tissue surrounding the tumor, whereas the accumulation of FDG is associated with the metabolic activity of the tumor itself. An FDG-PET study can therefore be used as a complementary study for the detection and follow-up of bone tumors when a Tc-99m-phosphate bone scintigram is negative..|
|124.||Masayuki Sasaki, Yuichi Ichiya, Shinichi Hosokawa, Makoto Otsuka, Yasuo Kuwabara, Toshimitsu Fukumura, Motohiro Kato, Ikuo Goto, Kouji Masuda, Regional cerebral glucose metabolism in patients with Parkinson's disease with or without dementia, Annals of Nuclear Medicine, 10.1007/BF03164661, 6, 4, 241-246, 1992.12, By means of positron emission tomography, the cerebral glucose metabolism in 5 patients with Parkinson's disease with dementia was compared with that in 9 patients without dementia, and that in 5 normal volunteers. The metabolic rates for glucose were measured by placing one hundred regions of interest. In the demented patients, cerebral glucose metabolism was diffusely decreased compared with that of the non-demented patients and the normal controls. The most significant decrease in glucose metabolism was observed in the angular gyrus (49.7% of the normal controls). The glucose metabolism in the cingulate, pre- and postcentral, occipital and subcortical regions was relatively spared (62.1 to 85.5% of the normal controls). In the patients without dementia, the glucose metabolism in each region was not significantly different from that in the normal controls. These results suggest that diffuse glucose hypometabolism in the cerebral cortex may correlate with that of patients with Parkinson's disease with dementia. © 1992 Springer-Verlag..|
|125.||Sasaki M, Ichiya Y, Kuwabara Y, Otsuka M, Fukumura T, Ejima J, Tsuda Y, Masuda K., Rapid myocardial perfusion imaging with 99mTc-teboroxime and a three-headed SPECT system: a comparative study with 201Tl. , Nucl Med Commun, 10.1097/00006231-199211000-00003, 13, 11, 790-794, 1992.11.|
|126.||M SASAKI, Y ICHIYA, Y KUWABARA, M OTSUKA, T FUKUMURA, JI EJIMA, Y TSUDA, K MASUDA, RAPID MYOCARDIAL PERFUSION IMAGING WITH 99TCM-TEBOROXIME AND A 3-HEADED SPECT SYSTEM - A COMPARATIVE-STUDY WITH TL-201, NUCLEAR MEDICINE COMMUNICATIONS, 13, 11, 790-794, 1992.11, Tc-99(m)-teboroxime is a new myocardial perfusion agent with a high first pass extraction and rapid myocardial washout. The usefulness of Tc-99(m)-teboroxime was evaluated for detection of myocardial ischaemia using a three-headed single photon emission tomography (SPECT) system which allows for rapid data acquisition. The subjects consisted of 14 patients, including seven with ischaemic heart disease, four with cardiomyopathy and three others. After the Tc-99(m)-teboroxime injection, dynamic data was collected every minute for 15 min with continuous rotation. High-quality SPECT images could be obtained by reconstructing the serial scans from 2 to 8 min. The sensitivity, specificity and accuracy of the Tc-99(m)-teboroxime study for the detection of the ischaemic region were not significantly different from those of the Tl-201 study. Myocardial clearance was slow in the ischaemic lesion and in the myocardium of cardiomyopathy patients, while the coronary angiograms did not show any abnormality. These results therefore indicate that the rapid SPECT imaging and myocardial clearance of Tc-99(m)-teboroxime obtained with a three-headed SPECT system were useful for the detection of myocardial ischaemia..|
|127.||M SASAKI, K SUGIO, T SASAZUKI, K-RAS ACTIVATION IN COLORECTAL TUMORS FROM PATIENTS WITH FAMILIAL POLYPOSIS-COLI, CANCER, 65, 11, 2576-2579, 1990.06.|
|128.||M SASAKI, Y ICHIYA, Y KUWABARA, M OTSUKA, T TAHARA, T FUKUMURA, R GUNASEKERA, K MASUDA, RINGLIKE UPTAKE OF [F-18] FDG IN BRAIN-ABSCESS - A PET STUDY, JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY, 14, 3, 486-487, 1990.05.|
|129.||M SASAKI, M OKAMOTO, C SATO, K SUGIO, J SOEJIMA, T IWAMA, T IKEUCHI, A TONOMURA, M MIYAKI, T SASAZUKI, LOSS OF CONSTITUTIONAL HETEROZYGOSITY IN COLORECTAL TUMORS FROM PATIENTS WITH FAMILIAL POLYPOSIS COLI AND THOSE WITH NONPOLYPOSIS COLORECTAL-CARCINOMA, CANCER RESEARCH, 49, 16, 4402-4406, 1989.08.|
|130.||OKAMOTO M, SASAKI M, SUGIO K, SATO C, IWAMA T, IKEUCHI T, TONOMURA A, SASAZUKI T, MIYAKI M, Loss of constitutional heterozygosity in colon carcinoma from patients with familial polyposis coli (共著), Nature, 10.1038/331273a0, 331, 6153, 273-277, 1988.01.|
|131.||M SASAKI, K SUGIO, JI SOEJIMA, T IKEUCHI, A TONOMURA, T IWAMA, J UTSUNOMIYA, T SASAZUKI, LACK OF ASSOCIATION AND LINKAGE BETWEEN HLA AND FAMILIAL POLYPOSIS-COLI, HUMAN GENETICS, 77, 1, 36-39, 1987.09.|