Kyushu University Academic Staff Educational and Research Activities Database
List of Presentations
Fujibuchi Toshioh Last modified date:2023.03.07

Professor / Devision of Medical Quantum Science / Department of Health Sciences / Faculty of Medical Sciences

1. Kotaro Kuroda, Kosuke Kaneko, Toshioh Fujibuchi, Yoshihiro Okada, Web-Based Collaborative VR Training System for Operation of Radiation Therapy Devices, 13th International Conference on Complex, Intelligent, and Software Intensive Systems, CISIS 2019, 2020.01, In this paper, the authors propose a web-based collaborative VR training system for the operation of radiation therapy devices. Medical students have to train as a therapist if they want to be so. However, radiation therapy devices are very expensive and dangerous, so any training systems without using the devices are needed. The authors have already proposed the web-based VR training system for the operation of medical therapy devices, and made preliminary tests to confirm which kinds of VR devices are suitable for the proposed system. From the test results, the authors chose one training system configuration of VR devices and implemented a more practical web-based collaborative VR training system..
2. Toshioh Fujibuchi, Current status of medical exposure in CT examination and patient dose management, 17th SEACOMP, 3rd PIT-FMB, 2019.08.
3. C. Anam, W. S. Budi, Toshioh Fujibuchi, F. Haryanto, G. Dougherty, Validation of the tail replacement method in MTF calculations using the homogeneous and non-homogeneous edges of a phantom, 18th Asia-Oceania Congress of Medical Physics, AOCMP 2018 and 16th South-East Asia Congress of Medical Physics, SEACOMP 2018, 2019.06, We validated the tail replacement technique in the modulation transfer function (MTF) calculation of CT images using edges of homogeneous and non-homogeneous phantom using an automated method. The algorithm for the automated MTF calculation consists of several steps. The upper edge of the phantom was detected from its axial image and pixel values was taken to create an edge spread function (ESF). The left tail of the ESF was flipped horizontally to replace the right tail. Differentiating the ESF produced a line spread function (LSF) which was Fourier transformed to produce the MTF. To validate the result for the non-homogeneous phantom was compared with that for a homogeneous phantom. Results showed that in the homogeneous module, the MTF curve generated without tail replacement corresponded to its shape in use. However for the non-homogeneous module, the MTF obtained without tail replacement differed considerably from its shape in use. The 50% value of MTF (MTF-50) without tail replacement was 0.44 cycles/mm compared to 0.33 cycles/mm in use. Using the tail replacement, the MTFs in the homogeneous and non-homogeneous modules were comparable, with MTF-50 values of 0.33 cycles/mm for both. In summary, the MTF cannot be conventionally measured from the edge of the non-homogeneous module, but it can be resolved using the tail replacement technique on the ESF curve..
4. C. Anam, Toshioh Fujibuchi, T. Toyoda, N. Sato, F. Haryanto, R. Widita, I. Arif, G. Dougherty, The impact of head miscentering on the eye lens dose in CT scanning
Phantoms study, 7th Asian Physics Symposium, APS 2017, 2019.05, The aim of this study was to evaluate the eye lens dose due to miscentering, either above or under the isocenter, and to assess the possibility of eye lens dose reduction by using miscentering phenomenon. We used two types of phantoms (head CTDI and adult anthropomorphic phantoms) and two types of detectors (pencil ionization chamber and radiophotoluminescence detectors). Measurements using the head CTDI phantom and pencil ionization chamber were performed at the upper peripheral hole of the CTDI phantom, whereas measurements using RPL detectors were performed on the surface of the eyes of the anthropomorphic phantom. Each measurement was performed with position phantoms at the isocenter and also at the positions ±2, ±4, and ±6 cm under and above the isocenter. The impact of miscentering on noise was also observed. Our results show that the dose to the eye decreases with increasing position of the phantoms from the isocenter, and increases with decreasing position of the phantoms from the isocenter. Miscentering above the isocenter can potentially reduce the dose to the eye lens, which is a sensitive organ to ionizing radiation..
5. C. Anam, F. Haryanto, R. Widita, I. Arif, Toshioh Fujibuchi, G. Dougherty, A size-specific effective dose for patients undergoing CT examinations, 7th Asian Physics Symposium, APS 2017, 2019.05, This study aims to develop a simple method for estimating the size-specific effective dose using the ImPACT software. The size-specific effective dose was calculated from the images of patients who underwent CT examinations of the thorax and abdomen regions. Volume computed tomography dose index (CTDIvol) and mAs data were obtained from the dose report. The average of mAs and CTDIvol were used to determine the normalized CTDIvol (nCTDIvol). Patient size was expressed in effective diameter (Deff), and was measured at nine slices along the z-axis. The normalized size-specific dose estimate (nSSDE) was then calculated. The normalized size-specific effective dose was obtained in the "effective dose" text-box by inputting an arbitrary value in the "CTDI (air)" text-box so that the "CTDIvol" text-box showed a similar value to the nSSDE. The results show that the normalized size-specific effective dose decreases exponentially with increasing patient size. The results are consistent with results of Sahbaee formula to within 20%..
6. Kotaro Kuroda, Kosuke Kaneko, Toshioh Fujibuchi, Yoshihiro Okada, Web-based VR system for operation training of medical therapy devices, 12th International Conference on Complex, Intelligent, and Software Intensive Systems, CISIS 2018, 2019.01, In this paper, the authors propose a web-based VR system for operation training of medical therapy devices. Currently, their target is one of the radiation therapy devices called TrueBeam. Medical students must train as a radiation therapist if they want to be so. However, for such training, there are several problems, e.g., radiation therapy devices cannot be used so easily because they are very expensive and dangerous. Therefore, any training systems are needed, and then, the authors propose the web-based VR system in this paper. Although currently, their target is the radiation therapy device, the proposed web-based VR system can be used for operation training of other medical therapy devices because it has a very feasible system architecture based on recent Web technology. Therefore, the proposed web-based VR system has an aspect as a development framework for operation training systems of other medical therapy devices..
7. Toshioh Fujibuchi, H. Kawamura, K. Yamanashi, A. Hiroki, S. Yamashita, M. Taguchi, Y. Sato, K. Mimura, H. Ushiba, T. Okihara, Dose-response measurement in gel dosimeter using various imaging modalities, 7th International Conference on 3D Radiation Dosimetry, IC3DDose 2012, 2013.01, Measurement methods that accurately measure radiation dose distribution in a three dimensional manner in order to allow comparisons of treatment plans are needed for quality assurance. One such measurement method involves the use of a polymer gel dosimeter to measure the dose distribution in three dimensions. During irradiation, a polymerization reaction makes new chemical bonds and induces changes of the chemical structure of the gel of the gel dosimeter. In the present study, dose-response measurement of an environment-friendly material used in the gel dosimeter was performed by imaging with computed tomography (CT) and R1, R2, and fluid-attenuated inversion-recovery (FLAIR) magnetic resonance imaging (MRI) under various imaging conditions. Dose-response characteristics in the gel dosimeter used in the experiment were observed at doses of 5-20 Gy administered by X-ray CT and MRI. Although the FLAIR signal was a relative value, the dose-response values with FLAIR were excellent compared to those with R1, R2, and CT. Determination of more appropriate imaging conditions could help expand the dose-response parameters of each measurement method..
8. Toshioh Fujibuchi, Y. Tanabe, T. Isobe, H. Kawamura, T. Terunuma, K. Yasuoka, T. Matsumoto, J. Nishiyama, H. Harano, T. Sakae, Convenient method of thermal neutron measurement using imaging plates in proton therapy, World Congress on Medical Physics and Biomedical Engineering: Radiation Protection and Dosimetry, Biological Effects of Radiation, 2009.12, In proton therapy, measurement of secondary neutron emission is important, because such radiation can influence the occurrence of secondary cancers and the radioactivity of the treatment room. In this study, we investigated the possibility of neutron detection using a neutron imaging plate (IP) and a general IP. The upper limit of measurable neutron fluence by an IP system is primarily controlled by the readout range of the scanner that is used. Within this limit, a reasonable linear response of the IP to a neutron fluence was maintained. To separate thermal neutron from other radiation, we covered a part of the IPs with 1.5 mm thick cadmium plates and 1.0 mm thick lead plates. The neutron IP was shielded from thermal neutrons by the cadmium cover and the measured intensity was reduced. However, in the general IP, the intensity increased slightly in the region covered with cadmium because of prompt gamma-ray production. A further increase in intensity occurred in the lead-covered region due to interaction with photons. Moreover, the neutron field was calculated by PHITS Monte Carlo simulations, and the elements of secondary radiation which were produced in the neutron IP and metal plates were confirmed. From the results of this study, thermal neutrons and other radiation could be detected by using IPs and cadmium plates, suggesting the potential of such devices as practical neutron detectors..