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Masayuki Sasaki Last modified date:2019.09.06

Professor / Graduate School of Medical Sciences, Faculty of Medicine, Department of Health Sciences, Medical Quantum Science
Department of Health Sciences
Faculty of Medical Sciences

Graduate School
Undergraduate School
Other Organization

Academic Degree
Country of degree conferring institution (Overseas)
Field of Specialization
Radiology, Nuclear Medicine
Total Priod of education and research career in the foreign country
Outline Activities
Research: Non-invasive in vivo molecular imaging of oncology using nuclear medicine technology,
maging of tumor metabolism and CNS function by positron emission tomography (PET)

Education: molecular imaging, nuclear medicine technology, Radiochemistry, History of Radiology
Research Interests
  • Molecular imaging of the oncology using PET/CT and SPECT/CT
    keyword : PET/CT, SPECT/CT, molecular imaging
  • Molecular imaging of the brain using PET/CT and SPECT/CT
    keyword : PET/CT, SPECT/CT, brain
Academic Activities
1. Akira Maebatake, Keishin Morita, Go Akamatsu, Yuji Tsutsui, Kazuhiko Himuro, Shingo Baba, Masayuki Sasaki., The influence of minimal misalignment on the repeatability of PET images examined by the repositioning of point sources., J Nucl Med Technol. , doi: 10.2967/jnmt.118.208835., 47, 1, 55-59, J Nucl Med Technol. 2019 Mar;47(1):55-59. , 2019.03.
2. Takahashi A, Baba S, Sasaki M., 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.
3. Wagatsuma K, Oda K, Sakata M, Inaji M, Miwa K, Sasaki M, Toyohara J, Ishii K., 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.
4. 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., doi: 10.2967/jnmt.117.204735., 39, 10, 268-273, J Nucl Med Technol. 2018 Sep;46(3):268-273., 2018.09.
5. Yuji Tsutsui, Hiromitsu Daisaki, Go Akamatsu, Takuro Umeda, Matsuyoshi Ogawa, Hironori Kajiwara, Shigeto Kawase, Minoru Sakurai, Hiroyuki Nishida, Keiichi Magota, Kazuaki Mori, Masayuki Sasaki, J-Hart study group., Multicentre analysis of PET SUV using vendor-neutral software: the Japanese Harmonization Technology (J-Hart) study, EJNMMI RESEARCH, 10.1186/s13550-018-0438-9, 8, EJNMMI Research 2018 Aug 20;8(1):83., 2018.08, Objective: The Japanese standardised uptake value (SUV) Harmonisation Technology (J-Hart) study aimed to determine the applicability of vendor-neutral software to SUV derived from positron emission tomography (PET) images. The effects of SUV harmonisation were evaluated based on the reproducibility of several scanners and the repeatability of individual scanners.
Methods: Images were acquired from 12 PET scanners at nine institutions. PET images were acquired over a period of 30 minutes from a National Electrical Manufacturers Association (NEMA) International Electrotechnical Commission (IEC) body phantom containing six spheres of different diameters and an 18F solution with a background activity of 2.65 kBq/mL and a sphere-to-background ratio of 4. The images were reconstructed to determine parameters for harmonisation and to evaluate reproducibility. PET images with 2-minute acquisition × 15 contiguous frames were reconstructed to evaluate repeatability. Various Gaussian filters (GF) with full-width at half maximum (FWHM) values ranging from 1 - 15 mm in 1-mm increments were also applied using vendor-neutral software. The SUVmax of spheres was compared with the reference range proposed by the Japanese Society of Nuclear Medicine (JSNM) and the digital reference object (DRO) of the NEMA phantom. The coefficient of variation (CV) of the SUVmax determined using 12 PET scanners (CVrepro) was measured to evaluate reproducibility. The CV of the SUVmax determined from 15 frames (CVrepeat) per PET scanner was measured to determine repeatability.
Results: Three PET scanners did not require an additional GF for harmonisation, whereas the other nine required additional FWHM values of GF ranging from 5 to 9 mm. The pre- and post-harmonisation CVrepro of six spheres were (means ± SD) 9.45% ± 4.69% (range, 3.83% - 15.3%) and 6.05% ± 3.61% (range, 2.30% - 10.7%), respectively. Harmonisation significantly improved the reproducibility of the PET SUVmax (P = 0.0055). The pre- and post-harmonisation CVrepeat of nine scanners were (means ± SD) 6.59% ± 1.29% (range, 5.00% - 8.98%) and 4.88% ± 1.64% range (2.65% - 6.72%), respectively. Harmonisation also significantly improved the repeatability of PET SUVmax (P < 0.0001).
Conclusion: Harmonizing SUV using vendor - neutral software produced SUVmax for 12 scanners that fell within the JSNM reference range of a NEMA body phantom and improved SUVmax reproducibility and repeatability..
6. 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. , doi: 10.22038/aojnmb.2018.10330, 6, 2, 120-128, 2018.02.
7. 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., doi: 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..
8. 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.
9. 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..
10. 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..
11. Yasuo Kawata, Hidetaka Arimura, Koujirou Ikushima, Ze Jin, Kento Morita, Chiaki Tokunaga, Hidetake Yabuuchi, 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, 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..
12. 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..
13. 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..
14. 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..
15. Yasuhiro Maruoka, Michinobu Nagao, Shingo Baba, Takuro Isoda, Yoshiyuki Kitamura, Yuzo Yamazaki, Koichiro Abe, Masayuki Sasaki, Kotaro Abe, Hiroshi Honda, Three-dimensional fractal analysis of 99m Tc-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, 2017.05, Objective Balloon 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 (99m Tc-MAA) single-photon emission computed tomography (SPECT). Patients and methods Forty 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 99m Tc-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 30 mmHg and less than or equal to 30 mmHg. Receiver operating characteristic analysis was carried out. Results BPA significantly improved TUV (595±204-885±214 ml, P<0.001) and reduced the laterality of uptake (238±147-135±131 ml, P<0.001). Patients with poor therapeutic response (post-BPA mPAP≥30 mmHg, 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. Conclusion 3D-FA using 99m Tc-MAA SPECT pulmonary perfusion scintigraphy enables a noninvasive evaluation of the response of CTEPH patients to BPA..
16. 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.
17. Koujiro Ikushima, 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.
18. 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.
19. 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.
20. H Shiba, 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.
21. TAKURO ISODA, Masayuki Sasaki, 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.
22. Go Akamatsu, Masayuki Sasaki, Automated PET-only quantification of amyloid deposition with adaptive template and empirically pre-defined ROI, PHYSICS IN MEDICINE AND BIOLOGY, 10.1088/0031-9155/61/15/5768, 61, 15, 5768-5780, 2016.08, アルツハイマー型認知症の診断に用いられるアミロイドPETの結果を自動的にかつ定量的に判定する方法を開発した。特にこの方法は、1)異なるヒトの脳を同一の型にそろえるためにPET画像のみで行えること、2)大脳皮質の中でも特にアミロイドが沈着する領域に絞って解析できること、を特徴としている。既存の方法との比較では、本法はより優れた診断結果が得られることが明らかとなった。.
23. Toshiki Takeshita, Masayuki Sasaki, The influence of respiratory motion on the cumulative SUV-volume histogram and fractal analyses of intratumoral heterogeneity in PET/CT imaging, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-016-1071-1, 30, 6, 393-399, 2016.07, Objective: The purpose of this study was to investigate the influence of respiratory motion on the evaluation of the intratumoral heterogeneity of FDG uptake using cumulative SUV-volume histogram (CSH) and fractal analyses. Methods: We used an NEMA IEC body phantom with a homogeneous hot sphere phantom (HO) and two heterogeneous hot sphere phantoms (HE1 and HE2). The background radioactivity of 18F in the NEMA phantom was 5.3kBq/mL. The ratio of radioactivity was 4:2:1 for [the HO and the outer rims of the HE1 and HE2 phantoms] : [the inner cores of the HE1 and HE2 phantoms] : [background]. Respiratory motion was simulated using a motion table with an amplitude of 2 cm. PET/CT data were acquired using Biograph mCT in motionless and moving conditions. The PET images were analyzed by both CSH and fractal analyses. The area under the CSH (AUC-CSH) and the fractal dimension (FD) were used as quantitative metrics. Results: In motionless conditions, the AUC-CSHs of the HO (0.80), HE1 (0.75) and HE2 (0.65) phantoms were different. They did not differ in moving conditions (HO, 0.63 ; HE1, 0.65 ; HE2, 0.60). The FD of the HO phantom (0.77) was smaller than the FDs of the HE1 (1.71) and HE2 (1.98) phantoms in motionless conditions, however the FDs of the HO (1.99) and HE1 (2.19) phantoms were not different from each other and were smaller than that of the HE2 (3.73) phantom in moving conditions. Conclusion: Respiratory motion affected the results of the CSH and fractal analyses for the evaluation of the heterogeneity of the PET/CT images. The influence of respiratory motion was considered to vary depending on the object size..
24. 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.
25. Akihiko Takahashi, Miwa Kenta, Masayuki Sasaki, Shingo Baba, A Monte Carlo study on 223Ra imaging for unsealed radionuclide therapy., Medical Physics, 10.1118/1.4948682, 43, 6, 2965-2974, 2016.06, アルファ線放出核種であるラジウム223は去勢抵抗性前立腺癌骨転移の核医学治療に用いられるため、治療線量の評価には定量的画像評価が必要である。本研究では、ラジウム223がアルファ崩壊の際に放出するガンマ線を利用したイメージングの至適撮像条件をモンテカルロシミュレーションにて検討した。この結果、中エネルギー用コリメータを用いて84kevのエネルギーピークにて画像化するのが最も優れていると考えられた。.
26. Daisuke Kidera, Masayuki Sasaki, The edge artifact in the point-spread function-based PET reconstruction at different sphere-to-background ratios of radioactivity, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-015-1036-9, 30, 2, 97-103, 2016.02.
27. 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.
28. Akira Maebatake, Masayuki Sasaki, Relationship between the image quality and noise-equivalent count in time-of-flight positron emission tomography, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-015-1032-0, 30, 1, 68-74, 2016.01.
29. Go Akamatsu, Masayuki Sasaki, Optimization of image reconstruction conditions with phantoms for brain FDG and amyloid PET imaging, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-015-1024-0, 30, 1, 18-28, 2016.01.
30. 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.
31. Go Akamatsu, Masayuki Sasaki, Influence of statistical fluctuation on reproducibility and accuracy of SUVmax and SUVpeak: a phantom study., J Nucl Med Technol, 10.2967/jnmt.115.161745., 43, 3, 222-226, 2015.09.
32. Yabuuchi H, 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.
33. 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.
34. 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.
35. 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.
36. Akihiko Takahashi, Himuro K, Yamashita Y, Komiya I, Shingo Baba, Masayuki Sasaki, Monte Carlo simulation of PET and SPECT imaging of 90Y., Med Phys, 10.1118/1.4915545., 42, 4, 1926-1935, 2015.04.
37. 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.
38. 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.
39. 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.
40. Fujibuchi Toshioh, Akihiro Nohtomi, Shingo Baba, Masayuki Sasaki, Komiya, Isao, Umedzu, Yoshiyuki, 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.
41. Taniguchi, Takafumi, Akamatsu, Go, Kasahara, Yukiko, Mitsumoto, Katsuhiko, Shingo Baba, Masayuki Sasaki, Tsutsui, Yuji, Himuro, Kazuhiko, Mikasa, Shohei, Kidera, Daisuke, Improvement in PET/CT image quality in overweight patients with PSF and TOF, ANNALS OF NUCLEAR MEDICINE, 10.1007/s12149-014-0912-z, 29, 1, 71-77, 2015.01, Objective: The aim of this study was to evaluate the effect of the point spread function (PSF) and time of flight (TOF) on PET/CT images of overweight patients in relation to the iteration number and the acquisition time. Methods: This study consisted of a phantom study and a clinical study. The NEMA IEC body phantom and a 40 cm diameter large phantom (LG phantom) simulating an overweight patient were used in this study. Both phantoms were filled with 18F solution with a sphere to background ratio of 4:1. The PET data were reconstructed with the baseline ordered-subsets expectation maximization (OSEM) algorithm, with the OSEM+PSF model, with the OSEM+TOF model and with the OSEM+PSF+TOF model. The clinical study was a retrospective analysis of 66 patients who underwent 18F-FDG PET/CT. The image quality was evaluated using the background variability (coefficient of variance, CVphantom and CVliver) and the contrast (CONTHOT and SNR). Results: In phantom study, the CVphantom of the LG phantom was higher than that of the NEMA phantom. The PSF decreased the CVphantom of the LG phantom to the NEMA phantom level. The TOF information accelerated the CVphantom plateau earlier. The best relationship between the CVphantom and the CONTHOT was observed for the OSEM+PSF+TOF. In clinical study, the combination of PSF and TOF decreased the CVliver for overweight patients to that for normal weight patients while it increased the SNR similarly between two patient groups. Conclusion: The combination of the PSF and TOF correction improved the image quality of the LG phantom and overweight patients..
42. 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.
43. 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.
We used a NEMA IEC body phantom filled with an 18F 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 (QH,10mm), background variability (N10mm) recovery coefficient (RC), and sphere volumes.
In regular motion patterns with ideal breathing and breathing with a pause period, the QH,10mm, RC and sphere volumes were not differed between AG-PET and PG-PET. In the variable amplitude pattern, the QH,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 (6.4mL vs 8.6mL). In the changing baseline pattern, the QH,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 (6.2mL vs 9.8ml). The N10mm did not differ between AG-PET and PG-PET, irrespective of the motion pattern.
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..
44. 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.
45. TAKURO ISODA, Shingo Baba, 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.
46. 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.
47. Go Akamatsu, K Uba, A Narisue, Takafumi Taniguchi, K Matsumoto, Yuji Tsutsui, Masayuki Sasaki, Impact of large axial field-of-view time-of-flight PET/CT for reducing whole-body acquisition time., J Nucl Med Technol, 42, 2, 101-104, 2014.05.
48. Shingo Baba, TAKURO ISODA, Yasuhiro Maruoka, Y Kitamura, Masayuki Sasaki, Tsuyoshi Yoshida, Hiroshi Honda, Diagnostic and Prognostic Value of Pretreatment SUV in 18F-FDG/PET in Breast Cancer: Comparison with Apparent Diffusion Coefficient from Diffusion-Weighted MR Imaging., J Nucl Med., doi: 10.2967/jnumed.113.129395., 55, 5, 736-742, 2014.05.
49. 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..
50. 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.
51. 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.
52. 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) ., DOI: 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,.
53. Yasuhiro Maruoka, Koichiro Abe, Shingo Baba, Takuro Isoda, Yoshio Matsuo, Kubo Y, Ogawa S, Yano T, Masayuki Sasaki, Hiroshi Honda, A case of pulmonary choriocarcinoma metastasis with unusual FDG-PET and CT findings: correlation with pathology., Ann Nucl Med. , 10.1007/s12149-012-0644-x. , Ann Nucl Med. 2012 Dec;26(10):835-9. doi: 10.1007/s12149-012-0644-x. Epub 2012 Aug 15., 2012.12, Ann Nucl Med. 2012 Dec;26(10):835-9. doi: 10.1007/s12149-012-0644-x. Epub 2012 Aug 15..
54. 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..
55. Go Akamatsu, Katsuhiko Mitsumoto, Kaori Ishikawa, Takafumi Taniguchi, Nobuyoshi Oya, Shingo Baba, Koichiro Abe, Masayuki Sasaki, Benefits of point-spread-function and time-of-flight for PET/CT image quality in relation to the body mass index and injected dose., Clin Nucl Med., 10.1097/RLU.0b013e31828da3bd., 2013.06, Clin Nucl Med. 2013 Jun;38(6):407-12. doi: 10.1097/RLU.0b013e31828da3bd.  Epub 2013 Apr 18.

The PET image quality of overweight patients and patients who receive low injected doses deteriorates because of increases in statistical noise. The purpose of this study was to investigate the benefits of the point-spread-function (PSF) and time-of-flight (TOF) for PET/CT image quality in such patients. Methods: The PET images were reconstructed using the baseline ordered-subsets expectation-maximization algorithm (OSEM), OSEM+PSF, OSEM+TOF and OSEM+PSF+TOF. In the phantom study, we used a NEMA body phantom with different radioactivity concentrations, and analyzed image quality using the coefficient of variance in the background (CVphantom). In the clinical study, we retrospectively studied 39 patients who underwent clinical 18F-FDG PET/CT. The patients were classified into groups based on body mass index and injected dose. Image quality was evaluated using the CV in the liver (CVliver). Results: In the phantom study, PSF and TOF improved the CVphantom, especially in low-activity models. Among all of the reconstructions, the best CVphantom was obtained with OSEM+PSF+TOF. In the clinical study, the CVliver of the low-dose group with OSEM+PSF+TOF was comparable to that of the high-dose group with conventional OSEM. Conclusion: PSF and TOF improved PET/CT image quality for overweight patients who received a lower injected dose. Therefore, the use of PSF and TOF is suggested to maintain the image quality of such patients without extending scanning times. It is greatly beneficial to obtain sufficient image quality for larger patients, especially in delivery institutions where the injection dose cannot be easily increased..
56. Yasuhiro Maruoka, Koichiro Abe, Shingo Baba, Takuro Isoda, Hirofumi Sawamoto, Tanabe Y, Masayuki Sasaki, Hiroshi Honda, Incremental Diagnostic Value of SPECT/CT with 131I Scintigraphy after Radioiodine Therapy in Patients with Well-differentiated Thyroid Carcinoma., Radiology, 10.1148/radiol.12112108. , Radiology. 2012 Dec;265(3):902-9. doi: 10.1148/radiol.12112108. Epub 2012 Sep 25., 2012.12, Radiology. 2012 Dec;265(3):902-9. doi: 10.1148/radiol.12112108. Epub 2012 Sep 25..
57. Go Akamatsu, Kaori Ishikawa, Katsuhiko Mitsumoto, Takafumi Taniguchi, Nobuyoshi Oya, Shingo Baba, Koichiro Abe, Masayuki Sasaki, Improvement in PET/CT image quality with a combination of the point-spread-function and time-of-flight in relation to the reconstruction parameters., J Nucl Med, 10.2967/jnumed.112.103861., 53, 11, 1716-1722, 2012.11, J Nucl Med. 2012 Nov;53(11):1716-22. doi: 10.2967/jnumed.112.103861. Epub 2012 Sep 4.

The aim of this study was to investigate the effects of the point-spread-function (PSF) and time-of-flight (TOF) on improving 18F-FDG PET/CT images in relation to reconstruction parameters and noise equivalent counts (NEC). Methods: This study consisted of a phantom study and a retrospective analysis of 39 consecutive patients who underwent clinical 18F-FDG PET/CT. The NEMA IEC body phantom with a 10-mm-diameter sphere was filled with an 18F-FDG solution with a 4:1 radioactivity ratio compared with the background. The PET data were reconstructed with the baseline OSEM algorithm, with the OSEM+PSF model, with the OSEM+TOF model, and with the OSEM+PSF+TOF model. We evaluated the image quality by visual assessment, the signal-to-noise ratio of the 10-mm sphere (SNR10mm), the contrast of the 10-mm sphere, and the coefficient of variance (CV) in the phantom study, and then determined the optimal reconstruction parameters. We also examined the effects of PSF and TOF on the image quality of clinical images using the signal-to-noise ratio in the liver (SNRliver) in relation to the NEC in the liver (NECliver). Results: In the phantom study, the SNR10mm was the highest for the OSEM+PSF+TOF model, and the highest value was obtained at iteration 2 for algorithms with the TOF, and 3 for those without the TOF. In terms of a post-smoothing filter FWHM, the high SNR10mm was obtained with no filtering or was smaller than 2 mm for algorithms with PSF, and was 4–6 mm for those without PSF. The balance between the contrast recovery and noise is different for algorithms with either PSF and/or TOF. A combination of PSF and TOF improved the SNR10mm, contrast and CV, especially with a small-FWHM Gaussian filter. In the clinical study, the SNRliver of the low-NECliver group in the OSEM+PSF+TOF model was compared to that of high-NECliver group in the conventional OSEM. The PSF+TOF improved the SNRliver by about 24.9±9.81%. Conclusion: A combination of PSF and TOF clearly improves the image quality, while the optimization of the reconstruction parameters is necessary to obtain the best performance of PSF and/or TOF. Furthermore, this combination has the potential to provide good image quality with either lower activity or shorter acquisition time, thus improving the patient comfort and reducing the radiation burden..
58. Asao K, Takaki A, Tominaga M, Sasaki M., The interpolated projection data estimation method improves the image quality of myocardial perfusion SPECT with a short acquisition time., Ann Nucl Med, 26 (2):123–130. Epub 2011 Oct 28., 2012.02, ANM 2012 February; 26 (2): 123–130. Epub 2011 Oct 28.
Objective: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 201Tl myocardial perfusion imaging (MPI) single photon emission computed tomography (SPECT) with a short acquisition time.
Methods:Forty patients with suspected ischemic heart disease underwent stress 201Tl-MPI SPECT. Both stress and delayed images were acquired by 4 cycles of 360° 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 201Tl-MPI SPECT using the normalized mean square error (NMSE).
Results: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-7 min (1.85±1.06%) was significantly lower than that of the Tl-90-7min (2.07±1.24%) (p<0.05). The degree of improvement by the IPDE method was significantly greater for the delayed 201Tl-MPI SPECT than for the stress 201Tl-MPI SPECT (p<0.05).
Conclusion:The IPDE method improved the image quality and secured the diagnostic ability of 201Tl-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 the possibility that the IPDE method can be useful as a supporting method for shortening the acquisition time of 201Tl-MPI SPECT..
59. Mitsumoto K, Abe K, Sakaguchi Y, Zhang T, Tachiya Y, Ohya N, Baba S, Sasaki M., Determination of the Optimal Acquisition Protocol of Breath-Hold PET/CT for the Diagnosis of Thoracic Lesions., Nucl Med Commun, 32(12):1148-54. Epub 2011 Sep 30., 2011.12, Nucl Med Commun 2011 Dec; 32(12): 1148-54. Epub 2011 Sep 30.
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2, BH3, BH4 and BH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 cm3, BH×5: 4.715.14 cm3, P<0.01) and increased the SUVmax (FB: 6.275.41, BH×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×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..
60. 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.
61. Yakabe M, Sakai S, Yabuuchi H, Matsuo Y, Kamitani T, Setoguchi T, Cho M, Masuda M, Sasaki M., Effect of Dose Reduction on the Ability of Digital Mammography to Detect Simulated Microcalcifications., J Digit Imaging, 23(5):520-6, 2010.10.
62. Sakaguchi Y, Mizoguchi N, Mitsumoto T, Mitsumoto K, Himuro K, Ohya N, Kaneko K, Baba S, Abe K, Onizuka Y, Sasaki M., A simple table lookup method for PET/CT partial volume correction using a point-spread function in diagnosing lymph node metastasis., Ann Nucl Med, 24 (8):585–591., 2010.10.
63. Sakaguchi Y, Mitsumoto T, Zhang T, Mitsumoto K, Tachiya Y, Ohya N, Sasaki M., Importance of gated CT acquisition for the quantitative improvement of the gated PET/CT in moving phantom., Ann Nucl Med, 24 (7): 507-514, 2010.08.
64. Mitsumoto T, Ohya N, Ichimiya A, Sakaguchi Y, Kiyota A, Abe K, Morishita J, Sasaki M, Diagnostic performance of Tc-99m HMPAO SPECT for early and late onset Alzheimer's disease: A clinical evaluation of linearization correction, Ann Nucl Med, 23(5):487-495., 2009.07.
65. 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.
66. Sasaki M, Kuwabara Y, Koga H, Nakagawa M, Chen T, Kaneko K, Hayashi K, Nakamura K, Masuda K, 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.
67. 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.
68. 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.
69. Sasaki M, Ichiya Y, Kuwabara Y, Yoshida T, Fukumura T, Masuda K., Benzodiazepine receptors in chronic cerebrovascular disease: comparison with blood flow and metabolism., J Nucl Med, 38, 11, 1693-1698, 1997.11.
70. Sasaki M, Kuwabara Y, Yoshida T, Nakagawa M, Fukumura T, Mihara F, Morioka T, Fukui M, Masuda K, A comparative study of thallium-201 SPET, carbon-11 methionine PET and fluorine-18 fluorodeoxyglucose PET for the differentiation of astrocytic tumors, Eur J Nucl Med, 10.1007/s002590050294, 25, 9, 1261-1269, Vol.25,No.9,pp.1262 - 1269, 1998.09.
71. Sasaki M, Ichiya Y, Kuwabara Y, Akashi Y, Yoshida T, Fukumura T, Murayama S, Ishida T, Sugio K, Masuda K., 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., Eur J Nucl Med, 10.1007/BF00843701, 23, 7, 741-747, 1996.07.
72. Sasaki M, Sugio K, Sasazuki T., K-ras activation in colorectal tumors from patients with familial polyposis coli., Cancer, 10.1002/1097-0142(19900601)65:11<2576::AID-CNCR2820651130>3.0.CO;2-4, 65, 11, 2576-2579, 1990.06.
73. 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. , Nature (Lond.), 10.1038/331273a0, 331, 6153, 273-277, 1988.01.
74. Sasaki M, Okamoto M, Sato C, Sugio K, Soejima J, Iwama T, Ikeuchi T, Tonomura A, Miyaki M, Sasazuki T:, Loss of constitutional heterozygosity in colorectal tumors from patients with familial polyposis coli and those with non-polyposis colorectal carcinoma. , Cancer Res, 49, 16, 4402-4406, 1989.08.
Membership in Academic Society
  • Japanese Society of Nuclear Medicine
  • Japan Radiological Society
  • Japanese Society for Therapeutic Radiology and Oncology
  • Society of Nuclear Medicine
  • The Japanese Cancer Association
  • The Japan Lung Cancer Society
  • Japan Radioisotope Association
Educational Activities
Department of Health Sciences, School of Medicine,
Molecular imaging, Nuclear medicine technology, Radiochemistry, History of Radiology