研究者詳細 - 平野　祥之

論文 - 平野　祥之

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Measurements of temporal response of luminescence of water at lower energy than Cerenkov-light threshold during carbon-ion irradiation

Yamamoto, S; Akagi, T; Hirano, Y; Komori, M

BIOMEDICAL PHYSICS & ENGINEERING EXPRESS 6 巻 ( 4 ) 頁： 045002 2020年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Biomedical Physics and Engineering Express

Although the luminescence of water at lower energy than the Cerenkov-light threshold during carbon-ion irradiation was found and imaging was possible, the temporal response has not been measured, and so the difference from Cerenkov-light remains unclear. To clarify this point, we measured the temporal response of the luminescence of water at lower energy than the Cerenkov-light threshold and compared it with that of Cerenkov-light. We used silicon photomultiplier (Si-PM) modules to measure the temporal response at the Bragg peak area of a water phantom during irradiation of the carbon ion where the Cerenkov-light was not included. We also measured the temporal response at the shallow depth of the water phantom where the Cerenkov-light was included. In both areas, we measured the temporal waveforms of the light produced by the irradiation of the carbon ions in which the ripples of spills were clearly observed. We found no difference in the waveforms between the Bragg peak and the shallow depths of water. Our results do not contradict the hypothesis that the luminescence of water and Cerenkov-light are produced by the same mechanism.

DOI： 10.1088/2057-1976/ab8b7e

Radioluminescence by synchrotron radiation with lower energy than the Cherenkov light threshold in water

Hirano, Y; Komori, M; Onoda, D; Nagae, T; Yamamoto, S

JOURNAL OF PHYSICS COMMUNICATIONS 4 巻 ( 7 ) 2020年7月

記述言語：日本語出版者・発行元：Journal of Physics Communications

Radioluminescence by protons and carbon ions of energy lower than the Cherenkov threshold (∼260 keV) in water has been observed. However, the origin of the luminescence has not been investigated well. In the present work, we imaged radioluminescence in water using synchrotron radiation that was of sufficiently lower energy (11 keV) than the Cherenkov threshold and we measured its spectrum using a high-sensitivity cooled CCD camera and optical longpass filters having 5 different thresholds. In addition, to determine effects of impurities in water, the water target was changed from ultrapure water to tap water. Monte Carlo simulation (Geant4) was also performed to compare its results with the experimentally obtained radioluminescence distribution. In the simulation, photons were generated in proportion to the energy deposition in water. As a result, the beam trajectory was clearly imaged by the radioluminescence in water. The spectrum was proportional to λ−3.4±0.4 under an assumption of no peaks. In the spectrum and distribution, no differences were observed between ultrapure water and tap water. TOC (total organic carbon) contents of ultrapure water and tap water as an impurity were measured and these were 0.26 mg l−1 and 2.3 mg l−1, respectively. The radioluminescence seemed to be attributable to water molecules not impurities. The radioluminescence distribution of the simulation was consistent with the experimental distribution and this suggested that radioluminescence was proportional to dose, which is expected to allow use for dose measurement.

DOI： 10.1088/2399-6528/ab9f8d

Development of an ultrahigh-resolution radiation real-time imaging system to observe trajectory of alpha particles in a scintillator

Yamamoto, S; Hirano, Y; Kamada, K; Yoshikawa, A

RADIATION MEASUREMENTS 134 巻 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Radiation Measurements

The high-resolution imaging of alpha particles is required for the development of radio-compounds for targeted alpha-particle therapy or alpha emitter detection at nuclear facilities. Therefore, we developed an ultrahigh-resolution, real-time alpha-particle imaging system for observing the trajectories of alpha particles in a scintillator. The developed alpha-particle imaging system is made from a 1-μm-diameter fiber-structure scintillator plate that is optically coupled with the first of two sequentially connected tapered optical fiber plates. The output of the second, larger tapered optical fiber plate was imaged by an electron-multiplied (EM) cooled CCD camera. With our developed imaging system, we observed images of alpha particles having a spatial resolution of ~11 μm. We could also observe the trajectories of alpha particles with Bragg peaks for the angled incident alpha particles. We conclude that this imaging system, which can observe the trajectory of alpha particles in a fiber-structure scintillator, is promising for research on targeted alpha-particle therapy or alpha emitter detection at nuclear facilities.

DOI： 10.1016/j.radmeas.2020.106368

Biological washout modelling for in-beam PET: rabbit brain irradiation by <SUP>11</SUP>C and <SUP>15</SUP>O ion beams

Toramatsu, C; Mohammadi, A; Wakizaka, H; Seki, C; Nishikido, F; Sato, S; Kanno, I; Takahashi, M; Karasawa, K; Hirano, Y; Yamaya, T

PHYSICS IN MEDICINE AND BIOLOGY 65 巻 ( 10 ) 頁： 105011 2020年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physics in Medicine and Biology

Positron emission tomography (PET) has been used for dose verification in charged particle therapy. The causes of washout of positron emitters by physiological functions should be clarified for accurate dose verification. In this study, we visualized the distribution of irradiated radioactive beams, 11C and 15O beams, in the rabbit whole-body using our original depth-of-interaction (DOI)-PET prototype to add basic data for biological washout effect correction. Time activity curves of the irradiated field and organs were measured immediately after the irradiations. All data were corrected for physical decay before further analysis. We also collected expired gas of the rabbit during beam irradiation and the energy spectrum was measured with a germanium detector. Irradiated radioactive beams into the brain were distributed to the whole body due to the biological washout process, and the implanted 11C and 15O ions were concentrated in the regions which had high blood volume. The 11C-labelled 11CO2 was detected in expired gas under the 11C beam irradiation, while no significant signal was detected under the 15O beam irradiation as a form of C15O2. Results suggested that the implanted 11C ions form molecules that diffuse out to the whole body by undergoing perfusion, then, they are incorporated into the blood-gas exchange in the respiratory system. This study provides basic data for modelling of the biological washout effect.

DOI： 10.1088/1361-6560/ab8532

Scintillator screen for measuring low-dose halo in scanning carbon-ion therapy

Yogo, K; Tatsuno, Y; Souda, H; Matsumura, A; Tsuneda, M; Hirano, Y; Ishiyama, H; Saito, A; Ozawa, S; Nagata, Y; Nakano, T; Hayakawa, K; Kanai, T

RADIATION MEASUREMENTS 133 巻 2020年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Radiation Measurements

To ensure safe administration and quality assurance (QA) of scanning carbon-ion therapy doses, an efficient and reliable method to measure the lateral dose profile of a carbon-ion pencil beam, including the low-dose halo, is required. We developed a simple, expeditious dose measurement tool that employs a silver-activated zinc sulfide (ZnS) scintillator, which shows a low linear energy transfer (LET) dependency, to measure the low-dose halo of a carbon-ion pencil beam with high spatial resolution.

DOI： 10.1016/j.radmeas.2020.106299

Estimations of relative biological effectiveness of secondary fragments in carbon ion irradiation of water using CR-39 plastic detector and microdosimetric kinetic model 査読有り

Hirano Y., Kodaira S., Souda H., Osaki K., Torikoshi M.

Medical Physics 47 巻 ( 2 ) 頁： 781 - 789 2020年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Medical Physics

Purpose: To estimate relative biological effectiveness (RBE) ascribed to secondary fragments in a lateral distribution of carbon ion irradiation. The RBE was estimated with the microdosimetric kinetic (MK) model and measured linear energy transfer (LET) obtained with CR-39 plastic detectors. Methods: A water phantom was irradiated by a 12C pencil beam with energy of 380 MeV/u at the Gunma University Heavy Ion Medical Center (GHMC), and CR-39 detectors were exposed to secondary fragments. Because CR-39 was insensitive to low LET, we conducted Monte Carlo simulations with Geant4 to calculate low LET particles. The spectra of low LET particles were combined with experimental spectra to calculate RBE. To estimate accuracy of RBE, we calculated RBE by changing yield of low LET particles by ± 10% and ± 40%. Results: At a small angle, maximum RBE by secondary fragments was 1.3 for 10% survival fractions. RBE values of fragments gradually decreased as the angle became larger. The shape of the LET spectra in the simulation reproduced the experimental spectra, but there was a discrepancy between the simulation and experiment for the relative yield of fragments. When the yield of low LET particles was changed by ± 40%, the change in RBE was smaller than 10%. Conclusions: An RBE of 1.3 was expected for secondary fragments emitted at a small angle. Although, we observed a discrepancy in the relative yield of secondary fragments between simulation and experiment, precision of RBE was not so sensitive to the yield of low LET particles.

DOI： 10.1002/mp.13916

Estimation of dose and light distributions in water during irradiation of muon beams

Hirano, Y; Ninomiya, K; Yamamoto, S

PHYSICA SCRIPTA 94 巻 ( 12 ) 2019年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physica Scripta

High-intensity muon beams are now available at the Japan Proton Accelerator Research Complex and their use in radiotherapy may become possible in the future. Dose and range estimation are therefore important and optical imaging of the dose or range may be a promising method for that purpose. We calculated the dose and light distributions in water during irradiation of a positive muon beam using Monte Carlo simulation. First, we simulated the dose deposited in water for pencil beams with 30 and 50 MeV positive muons. We were able to clearly identify the Bragg peak in the depth dose profiles by muons and observed that the dose from positrons are added to the Bragg peak area with a ∼10% muon dose. We also found that the lateral dose widths increased as the depth increased and that it was ∼3-5 times wider at the Bragg peak position. With the light distribution of the muon in water, light produced by the positrons was dominant and distributed around the Bragg peak, and the peak positions were estimated within 2 mm differences of the peak position of the dose distributions. It is therefore possible to monitor the Bragg peak position of muons using an optical method.

DOI： 10.1088/1402-4896/ab3acb

Scintillator screen for measuring dose distribution in scanned carbon-ion therapy 査読有り

Yogo, K; Tatsuno, Y; Souda, H; Matsumura, A; Tsuneda, M; Hirano, Y; Ishiyama, H; Saito, A; Ozawa, S; Nagata, Y; Nakano, T; Hayakawa, K; Kanai, T

RADIATION MEASUREMENTS 129 巻 2019年10月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Radiation Measurements

Precise measurement of the dose distribution of a carbon-ion pencil beam is essential for the safe delivery of treatment in scanned carbon-ion therapy. We developed an easy-to-use and quick dose-measurement tool that employs a silver-activated zinc-sulfide (ZnS) scintillator, which shows a smaller linear energy transfer (LET) dependency than conventional Gd-based scintillator, to measure the dose distribution of a carbon-ion pencil beam with high spatial resolution and small corrections. A ZnS scintillator sheet was set up perpendicular to the beam axis, and scintillation images were recorded using a charge-coupled device camera. We used 290-MeV/nucleon monoenergetic carbon-ion pencil beams at the Gunma University Heavy Ion Medical Center. The thickness of the water tank placed above the scintillator was remotely controlled to adjust the measurement depth. Images were acquired at different water depths, and the depth and lateral profiles were determined from the images. The results were compared with those of conventional Gd-based scintillator. The depth–light intensity profile of the ZnS scintillator matched the depth dose measured using an ionization chamber, which was better than that of a Gd-based scintillator. This result is advantageous for measurements using a carbon-ion pencil beam, which consists of primary carbon ions with a much higher LET than a proton, with smaller corrections. The ZnS scintillator showed good output characteristics, dose linearity (R2 > 0.99), and output reproducibility (deviations below 2%) and good agreement with the lateral-dose profiles measured using a diode down to ~1% of the central dose. The proposed tool can measure lateral profiles at the depth of the Bragg peak and tail in addition to the entrance. Our tool was used to quickly measure the dose distribution of carbon-ion pencil beam with high-spatial resolution and small corrections.

DOI： 10.1016/j.radmeas.2019.106207

Estimation of the fractions of luminescence of water at higher energy than Cerenkov-light threshold for various types of radiation 国際誌

Hirano, Y; Yamamoto, S

JOURNAL OF BIOMEDICAL OPTICS 24 巻 ( 6 ) 頁： 1 - 9 2019年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Biomedical Optics

Although the luminescence of water at a lower energy than the Cerenkov-light (CL) threshold has been found for various types of radiation, the fractions of the luminescence of water to the total produced light have not been obvious for radiations at a higher energy than the CL threshold because it is difficult to separate these two types of light. Thus, we used a Monte Carlo simulation to estimate the fractions of the luminescence of water for various types of radiation at a higher energy than the CL threshold to confirm the major component of the produced light. After we confirmed that the estimated light production of the luminescence of water could adequately simulate the experimental results, we calculated the produced light photons of this luminescence and the CL from water for protons (170 MeV), carbon ions (330 MeV/n), high-energy x-ray (6 MV) from a linear accelerator (LINAC), high-energy electrons (9 MeV) from LINAC, positrons (F-18, C-11, O-15, and N-13), and high-energy gamma photon radionuclides (Co-60). For protons, the major fraction of the produced light was the luminescence of water in addition to the CL from the prompt gamma photons produced by the nuclear interactions. For carbon ions, the major fraction of the produced light was the luminescence of water and the CL produced by the secondary electrons in addition to the prompt gamma photons produced by the nuclear interactions. For high-energy x-ray and electrons from LINAC, the fractions of luminescence of water were 1/40.1 % to 0.2%. The fractions of luminescence of water for positrons were 0.2% to 1.5% and that for Co-60 was 0.4%. We conclude that the major fractions of light produced from x-ray and electrons from LINAC, positron radionuclides, and the Co-60 source are CL, with fractions of the luminescence of water from <0.1 % to 1.5%.

DOI： 10.1117/1.JBO.24.6.066005

Estimation of the three-dimensional (3D) dose distribution of electron beams from medical linear accelerator (LINAC) using plastic scintillator plate

Horita, R; Yamamoto, S; Yogo, K; Hirano, Y; Okudaira, K; Kawabata, F; Nakaya, T; Komori, M; Oguchi, H

RADIATION MEASUREMENTS 124 巻頁： 103 - 108 2019年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Radiation Measurements

Measurements of three-dimensional (3D) dose distribution of electron-beams in water are important for high-energy electron beams from medical linear accelerators (LINAC). Although ionization chambers are commonly used for this purpose, measurements take a long time for precise 3D dose distribution. To solve the problem, we tried the measurements of the 3D dose distributions using a scintillator plate combined with a mirror. After we placed a 1 mm thick plastic scintillator plate at the upper inside of a black box, a water phantom was set above the plastic scintillator plate outside the black box, and electron beam was irradiated to the water phantom from the upper side. The attenuated electron-beam by the water in the phantom was detected by the plastic scintillator plate and the scintillation image was formed in the plate. The image was reflected by a surface mirror set below the plastic scintillator plate and detected by a cooled charge coupled device (CCD) camera from the side. We changed the depths of the water in the phantom, obtained the scintillation images, and calculated a 3D scintillation image using the measured images. Measurements were made for 9 MeV and 12 MeV electron-beams using the imaging system. From the images, we could successfully form 3D scintillation images. The depth profiles measured from the 3D images showed almost identical distribution with those calculated by the planning system within the difference of 5%. The lateral profiles also showed almost identical within the difference of the widths less than 2.5 mm. We conclude that the proposed method is promising for 3D dose distribution measurements of electron-beams.

DOI： 10.1016/j.radmeas.2019.04.002

Comparison of Noise Equivalent Count Rates (NECRs) for the PET Systems With Different Ring Diameter and Electronics

Nakanishi, K; Hirano, Y; Yamamoto, S

IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 3 巻 ( 3 ) 頁： 371 - 376 2019年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE Transactions on Radiation and Plasma Medical Sciences

Because the sensitivity of positron emission tomography (PET) system increases in proportion to the inverse of the diameter of the detector ring, brain PET systems are being planned and developed. However, count losses due to the dead-time of the detector blocks increases as the ring diameter decreases. Since the count losses decrease the noise equivalent count rate (NECR) of the system, the NECR of brain PET system may be lower than that of a whole-body PET system in clinical dose range. In this paper, we compared the NECRs of brain PET systems with that of a whole-body PET system using a Monte Carlo simulation. We simulated the PET system for a 27-cm-diameter detector ring, a 54-cm-diameter detector ring, and an 89-cm-diameter detector ring and evaluated the NECRs. In the clinical dose range, the NECR of the small-diameter brain PET system was lower than those of the whole-body PET system unless the electronics was advanced. We conclude that the small-diameter brain PET system with conventional electronics has not so much advantage except for the lower cost and the higher spatial resolution. However, advanced electronics can reduce degradation of NECR, so the small-diameter brain PET system with advanced electronics will be useful for clinical studies.

DOI： 10.1109/TRPMS.2018.2876410

Angular dependencies of Cerenkov-light in water for carbon-ion, high energy x-ray and electron

Hirano, Y; Yamamoto, S

BIOMEDICAL PHYSICS & ENGINEERING EXPRESS 5 巻 ( 2 ) 2019年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Biomedical Physics and Engineering Express

Because Cerenkov light is emitted above the threshold energy of the electrons (∼260 keV) in water and is emitted to forward directions, the light intensity distributions are different from the dose for x-ray and electron from LINAC. Cerenkov-light component was also observed with the depth profiles in carbon-ion. However the angular dependencies of the Cerenkov-light distributions were not obvious. Thus we calculated the depth profiles of the produced light distributions for 240 MeV n-1 carbon-ion, 6 MV x-ray, and 9 MeV electrons using Monte Carlo simulation. After we confirmed the simulation accuracies by comparing with the measured results, we calculated the depth profiles of luminescence of water and Cerenkov-light with various angles for these three types of radiations. With the simulation results, it became obvious that the depth profiles were significantly different with the angles for the produced light containing the Cerenkov-light. Cerenkov-light components were much higher at the larger angles. We also found the almost identical depth profile to dose with the angle of 10 degree to the right angle of the beam direction for 6 MV x-ray.

DOI： 10.1088/2057-1976/ab05b0

Linear energy transfer (LET) spectra and survival fraction distribution based on the CR-39 plastic charged-particle detector in a spread-out Bragg peak irradiation by a <SUP>12</SUP>C beam

Hirano, Y; Kodaira, S; Souda, H; Matsumura, A; Torikoshi, M

PHYSICS IN MEDICINE AND BIOLOGY 63 巻 ( 18 ) 頁： 185006 2018年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physics in Medicine and Biology

Facilities for heavy ion therapies are steadily increasing in number worldwide. One of the advantages of heavy ions is their high relative biological effect (RBE). In a model used at NIRS (National Institute of Radiological Sciences), linear energy transfer (LET) spectra are required to estimate biological dose (physical dose × RBE). The CR-39 plastic charged-particle detector (CR-39) is suitable for measurement of LET. For the present study, done at the Gunma University Heavy Ion Medical Center (GHMC), we measured LET spectra at 11 depths in spread-out Bragg peak (SOBP) irradiation by a 12C beam of 380 MeV/u. The lower threshold of the CR-39 to measure LET was about 5 keV μm-1 due to poor sensitivity for low LET. Then we calculated biological dose and survival fraction distributions and compared them with treatment planning results at GHMC. We used Monte Carlo simulation (Geant4) to calculate LET spectra. The simulation results were in good agreement with the experimental spectra. Moreover, the biological dose and survival fraction distributions estimated from the CR-39 reproduced the treatment planning. The CR-39 is suitable for estimating biological dose in carbon ion therapy.

DOI： 10.1088/1361-6560/aadaa6

陽子線、炭素線及びネオン線照射による水の発光効率のLET依存性

小森雅孝, 平野祥之, 矢部卓也, 堀田遼, 米内俊祐, 歳藤利行, 山本誠一

日本放射線技術学会雑誌 74 巻 ( 9 ) 頁： 1004 - 1004 2018年9月

Addition of luminescence process in Monte Carlo simulation to precisely estimate the light emitted from water during proton and carbon-ion irradiation

Yabe, T; Sasano, M; Hirano, Y; Toshito, T; Akagi, T; Yamashita, T; Hayashi, M; Azuma, T; Sakamoto, Y; Komori, M; Yamamoto, S

PHYSICS IN MEDICINE AND BIOLOGY 63 巻 ( 12 ) 頁： 125019 2018年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physics in Medicine and Biology

Although luminescence of water lower in energy than the Cerenkov-light threshold during proton and carbon-ion irradiation has been found, the phenomenon has not yet been implemented for Monte Carlo simulations. The results provided by the simulations lead to misunderstandings of the physical phenomenon in optical imaging of water during proton and carbon-ion irradiation. To solve the problems, as well as to clarify the light production of the luminescence of water, we modified a Monte Carlo simulation code to include the light production from the luminescence of water and compared them with the experimental results of luminescence imaging of water. We used GEANT4 for the simulation of emitted light from water during proton and carbon-ion irradiation. We used the light production from the luminescence of water using the scintillation process in GEANT4 while those of Cerenkov light from the secondary electrons and prompt gamma photons in water were also included in the simulation. The modified simulation results showed similar depth profiles to those of the measured data for both proton and carbon-ion. When the light production of 0.1 photons/MeV was used for the luminescence of water in the simulation, the simulated depth profiles showed the best match to those of the measured results for both the proton and carbon-ion compared with those used for smaller and larger numbers of photons/MeV. We could successively obtain the simulated depth profiles that were basically the same as the experimental data by using GEANT4 when we assumed the light production by the luminescence of water. Our results confirmed that the inclusion of the luminescence of water in Monte Carlo simulation is indispensable to calculate the precise light distribution in water during irradiation of proton and carbon-ion.

DOI： 10.1088/1361-6560/aac74b

Washout effect in rabbit brain: In-beam PET measurements using <sup>10</sup>C, <sup>11</sup>C and <sup>15</sup>O ion beams

Toramatsu C., Yoshida E., Wakizaka H., Mohammadi A., Ikoma Y., Tashima H., Nishikido F., Kitagawa A., Karasawa K., Hirano Y., Yamaya T.

Biomedical Physics and Engineering Express 4 巻 ( 3 ) 2018年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Biomedical Physics and Engineering Express

In particle therapy, in-beam positron emission tomography (PET) is expected to enable in situ noninvasive confirmation of the treatment delivery. For accurate range and dose verification or three-dimensional (3D) volume imaging, however, correction of the biological washout effect in a living body is necessary. In this study, we measured the washout rate in a rabbit brain using the recently developed technology for oxygen beam radiation as well as carbon ion beam radiation. To measure components of washout, three radionuclides, 10C, 11C and 15O, which were generated as secondary beams in the Heavy Ion Medical Accelerator in Chiba (HIMAC), were irradiated on the rabbit brain under two conditions, live and dead. In-beam data were acquired by our whole body dual-ring OpenPET, which enables 3D in-beam imaging. Regions of interests (ROIs) were set as a 3D positron distribution and the time activity curves (TACs) of the irradiated field were acquired. We obtained the washout rate for those conditions based on multiple component model analysis. A difference between washout speed in 11C ions and the 15O ions was observed. The observed medium and slow biological decay rates of 11C ions in rabbit brain were 0.30 min-1 and 0.004 min-1, respectively. Those values were consistent with the previous rabbit study results acquired by other imaging modalities, such as the pair of positron cameras or our single-ring small animal OpenPET prototype. The observed medium and slow biological decay rates of 15O ions were 0.72 min-1 and 0.024 min-1, respectively, which were faster than those of the 11C ion. Also, the medium biological decay rate of 15O ions was close to the washout rate in cerebral blood flow (CBF) measurements by dynamic PET with 15O-labeled water. These results should help to establish an accurate washout correction model.

DOI： 10.1088/2057-1976/aaade7

A carbon CT system: how to obtain accurate stopping power ratio using a Bragg peak reduction technique.

Lee SH, Sunaguchi N, Hirano Y, Kano Y, Liu C, Torikoshi M, Ohno T, Nakano T, Kanai T

Physics in medicine and biology 63 巻 ( 3 ) 頁： 035025 2018年2月

Predictors of biologic discontinuation due to insufficient response in patients with rheumatoid arthritis who achieved clinical remission with biologic treatment: A multicenter observational cohort study

Asai Shuji, Fujibayashi Takayoshi, Oguchi Takeshi, Hanabayashi Masahiro, Hayashi Masatoshi, Matsubara Hiroyuki, Ito Takayasu, Yabe Yuichiro, Watanabe Tsuyoshi, Hirano Yuji, Kanayama Yasuhide, Kaneko Atsushi, Kato Takefumi, Takagi Hideki, Takahashi Nobunori, Funahashi Koji, Takemoto Toki, Asai Nobuyuki, Watanabe Tatsuo, Ishiguro Naoki, Kojima Toshihisa

MODERN RHEUMATOLOGY 28 巻 ( 2 ) 頁： 221 - 226 2018年

Influences of 3D PET scanner components on increased scatter evaluated by a Monte Carlo simulation. 査読有り

Hirano Y, Koshino K, Iida H

Physics in medicine and biology 62 巻 ( 10 ) 頁： 4017 - 4030 2017年5月

Induced radioactivity of a GSO scintillator by secondary fragments in carbon ion therapy and its effects on in-beam OpenPET imaging 査読有り

Hirano Y, Nitta M, Nishikido F, Yoshida E, Inadama N, Yamaya T

61 巻頁： 4870-89 2016年

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