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Journal Articles

Establishment of a practical methodology for evaluating equieffective dose of individual patients based on RT-PHITS

Sato, Tatsuhiko; Furuta, Takuya; Sasaki, Hidetaka*; Watabe, Tadashi*

EJNMMI Physics (Internet), 12, p.28_1 - 28_16, 2025/03

 Times Cited Count:0

Journal Articles

Calculations of mean quality factors and their implications for organ-specific Relative Biological Effectiveness (RBE) in analysis of radiation-related risk in the atomic bomb survivors

Shimizu, Shota*; Sato, Tatsuhiko; Endo, Akira; 5 of others*

Radiation Research, 203(3), p.155 - 162, 2025/03

 Times Cited Count:0 Percentile:0.00(Biology)

Journal Articles

The Impact of ENSO on near-surface Beryllium-7

Schaar, K.*; Spiegl, T.*; Sato, Tatsuhiko; Langematz, U.*

Journal of Environmental Radioactivity, 282, p.107592_1 - 107592_14, 2025/02

 Times Cited Count:0 Percentile:0.00(Environmental Sciences)

Journal Articles

Relationships between protection and operational dosimetric quantities for external exposure to natural background radiation

Ulanowski, A.*; Sato, Tatsuhiko; Petoussi-Henss, N.*; Balonov, M.*

Radiation and Environmental Biophysics, 11 Pages, 2025/02

 Times Cited Count:1 Percentile:0.00(Biology)

Journal Articles

Development of a forward Monte Carlo based weight-window generator using the history-counter function in PHITS

Sato, Tatsuhiko; Hashimoto, Shintaro; M$'a$rquez Dami$'a$n, J. I.*; Niita, Koji*

Nuclear Instruments and Methods in Physics Research B, 557, p.165535_1 - 165535_8, 2024/12

 Times Cited Count:0 Percentile:0.00(Instruments & Instrumentation)

Journal Articles

Overview of PHITS Ver.3.34 with particular focus on track-structure calculation

Ogawa, Tatsuhiko; Hirata, Yuho; Matsuya, Yusuke; Kai, Takeshi; Sato, Tatsuhiko; Iwamoto, Yosuke; Hashimoto, Shintaro; Furuta, Takuya; Abe, Shinichiro; Matsuda, Norihiro; et al.

EPJ Nuclear Sciences & Technologies (Internet), 10, p.13_1 - 13_8, 2024/11

The latest updates on PHITS, a versatile radiation transport code, focusing specifically on track-structure models are presented. Track structure calculations are methods used to simulate the movement of charged particles while explicitly considering each atomic reaction. Initially developed for radiation biology, these calculation methods aimed to analyze the radiation-induced damage to DNA and chromosomes. Several track-structure calculation models, including PHITS-ETS, PHITS-ETS for Si, PHITS-KURBUC, ETSART, and ITSART, have been developed and implemented to PHITS. These models allow users to study the behavior of various particles at the nano-scale across a wide range of materials. Furthermore, potential applications of track-structure calculations have also been proposed so far. This collection of track-structure calculation models, which encompasses diverse conditions, opens up new avenues for research in the field of radiation effects.

Journal Articles

None

Sato, Tatsuhiko

Kenchiku Bosai, (562), p.16 - 19, 2024/11

no abstracts in English

Journal Articles

Application of radiation transport code PHITS to life sciences

Matsuya, Yusuke; Kai, Takeshi; Sato, Tatsuhiko

Shototsu, 21(3), p.R008_1 - R008_8, 2024/11

Particle and Heavy Ion Transport code System PHITS is a Monte Carlo code that enables the simulation of the behavior of radiation using a computer. Since 2018, a track-structure mode has been developed that allows the simulation of each atomic interaction in liquid water, which is a main component of living organisms. This development has made it possible to perform high-spatial resolution radiation track-structure analysis on the DNA scale. Meanwhile, based on the spatial information of atomic interactions calculated in the track-structure mode, we have also succeeded in developing an analysis code that enables the estimate of the various types of DNA damage yields efficiently and with high accuracy. In this review, we introduce an overview of the track-structure mode and DNA damage estimation model implemented in the latest version of PHITS, and show examples of applications of PHITS in the field of life sciences.

Journal Articles

LET-based approximation of the microdosimetric kinetic model for proton radiotherapy

Parisi, A.*; Furutani, K. M.*; Sato, Tatsuhiko; Beltran, C. J.*

Medical Physics, 51(10), p.7589 - 7605, 2024/10

 Times Cited Count:1 Percentile:57.45(Radiology, Nuclear Medicine & Medical Imaging)

In this study, we have developed an approximate MKM (microdosimetric kinetic model) based on LET (dose-averaged linear energy transfer) to address the challenges of biological relative effectiveness (RBE) models for proton therapy. This is an attempt to apply the mechanism-based approach used in carbon ion therapy to proton beams. This LET-based MKM establishes a correlation between dose-averaged LET and microbiological indices and successfully models survival rates for multiple cell lines. This has resulted in a mathematical description of RBE based on physical quantities that can be readily used in proton therapy planning systems.

Journal Articles

Comparative evaluation of two analytical functions for the microdosimetry of ions from $$^{1}$$H to $$^{238}$$U

Parisi, A.*; Furutani, K. M.*; Sato, Tatsuhiko; Beltran, C. J.*

Quantum Beam Science (Internet), 8(3), p.18_1 - 18_16, 2024/09

Journal Articles

Evaluation of relative biological effectiveness for diseases of the circulatory system based on microdosimetry

Sato, Tatsuhiko; Matsuya, Yusuke; Hamada, Nobuyuki*

Journal of Radiation Research (Internet), 65(4), p.500 - 506, 2024/07

 Times Cited Count:2 Percentile:78.29(Biology)

We therefore evaluated the mean and uncertainty of relative biological effectiveness (RBE) for diseases of the circulatory system (DCS) by applying a microdosimetric kinetic model specialized for RBE estimation of tissue reactions. For this purpose, we analyzed several RBE data for DCS determined by past animal experiments and evaluated the radius of the subnuclear domain best fit to each experiment as a single free parameter included in the model. Our analysis suggested that RBE for DCS tends to be lower than that for skin reactions, and their difference was borderline significant due to large variances of the evaluated parameters. These findings will help determine RBE by ICRP for preventing tissue reactions.

Journal Articles

Cell-cycle dependence on the biological effects of boron neutron capture therapy and its modification by polyvinyl alcohol

Matsuya, Yusuke; Sato, Tatsuhiko; Kusumoto, Tamon*; Yachi, Yoshie*; Seino, Ryosuke*; Miwa, Misako*; Ishikawa, Masayori*; Matsuyama, Shigeo*; Fukunaga, Hisanori*

Scientific Reports (Internet), 14, p.16696_1 - 16696_14, 2024/07

 Times Cited Count:3 Percentile:78.29(Multidisciplinary Sciences)

Boron neutron capture therapy (BNCT) is a unique radiotherapy to selectively eradicate tumor cells using boron compounds (e.g., 4-borono-L-phenylalanine [BPA]) that are heterogeneously taken up at the cellular level. However, the impacts of tempo-spatial heterogenicity on cell killing remain unclear. With the technical combination of radiation track detector, cell cycle analysis, and biophysical simulations, we demonstrated the cell cycle-dependent heterogenicity of BPA uptake and following biological impacts of $$^{10}$$B(n, $$alpha$$)$$^{7}$$Li reactions in HeLa cells expressing Fluorescent Ubiquitination-based Cell Cycle Indicators (FUCCI), as well as its modification effects of polyvinyl alcohol (PVA). As a result, we revealed that the intracellular BPA concentration in the S/G2/M phase was higher than that in the G1/S phase and that PVA modified the cell cycle dependence. Further, these findings lead to the development of the first BPA-PVA-based model for predicting BNCT treatment effects. These outcomes may contribute to more precision of therapeutic efficacy, when BNCT is combined with PVA and/or cell cycle-specific anticancer agents.

Journal Articles

The Role of deposition of cosmogenic $$^{10}$$Be for the detectability of solar proton events

Schaar, K.*; Spiegl, T.*; Langematz, U.*; Sato, Tatsuhiko; Mekhaldi, F.*; Kunze, M.*; Miyake, Fusa*; Yoden, Shigeo*

Journal of Geophysical Research; Atmospheres, 129(11), p.e2023JD040463_1 - e2023JD040463_28, 2024/06

 Times Cited Count:1 Percentile:46.64(Meteorology & Atmospheric Sciences)

Journal Articles

Monte Carlo simulation study on the dose and dose-averaged linear energy transfer distributions in carbon ion radiotherapy

Ishikawa, Akihisa; Koba, Yusuke*; Furuta, Takuya; Chang, W.*; Yonai, Shunsuke*; Matsumoto, Shinnosuke*; Hashimoto, Shintaro; Hirai, Yuta*; Sato, Tatsuhiko

Radiological Physics and Technology, 17(2), p.553 - 560, 2024/06

Journal Articles

Production rates of long-lived radionuclides $$^{10}$$Be and $$^{26}$$Al under direct muon-induced spallation in granite quartz and its implications for past high-energy cosmic ray fluxes

Sakurai, Hirohisa*; Kurebayashi, Yutaka*; Suzuki, Soichiro*; Horiuchi, Kazuho*; Takahashi, Yui*; Doshita, Norihiro*; Kikuchi, Satoshi*; Tokanai, Fuyuki*; Iwata, Naoyoshi*; Tajima, Yasushi*; et al.

Physical Review D, 109(10), p.102005_1 - 102005_18, 2024/05

 Times Cited Count:0 Percentile:0.00(Astronomy & Astrophysics)

Secular variations of galactic cosmic rays (GCRs) are inseparably associated with the galactic activities and should reflect the environments of the local galactic magnetic field, interstellar clouds, and nearby supernova remnants. The high-energy muons produced in the atmosphere by high-energy GCRs can penetrate deep underground and generate radioisotopes in the rock. As long lived radionuclides such as $$^{10}$$Be and $$^{26}$$Al have been accumulating in these rocks, concentrations of $$^{10}$$Be and $$^{26}$$Al can be used to estimate the long-term variations in high-energy muon yields, corresponding to those in the high-energy GCRs over a few million years. This study measured the production cross sections for muon induced $$^{10}$$Be and $$^{26}$$Al by irradiating positive muons with the momentum of 160 GeV/c on the synthetic silica plates and the granite core at the COMPASS experiment line in CERN SPS. In addition, it the contributions of the direct muon spallation reaction and the nuclear reactions by muon-induced particles on the production of long lived radionuclides in the rocks were clarified.

Journal Articles

Defense and forecast of space weather impact on social infrastructure, 4; Aircrew exposure

Sato, Tatsuhiko; Kubo, Yuki*

Purazuma, Kaku Yugo Gakkai-Shi, 100(5), p.218 - 223, 2024/05

One of the space weather hazards is the sudden occurrence of cosmic radiation exposure due to high-energy protons associated with massive solar flares. This paper focuses on cosmic radiation exposure for airline crew members, explaining the mechanisms and current regulations. Additionally, it introduces an overview of the recently developed Aircraft Radiation Exposure Warning System (WASAVIES) in Japan.

Journal Articles

The Impact of dose rate on responses of human lens epithelial cells to ionizing irradiation

Matsuya, Yusuke; Sato, Tatsuhiko; Yachi, Yoshie*; Date, Hiroyuki*; Hamada, Nobuyuki*

Scientific Reports (Internet), 14, p.12160_1 - 12160_14, 2024/05

 Times Cited Count:2 Percentile:78.29(Multidisciplinary Sciences)

Understand mechanisms of radiation cataracts that are of concern in the field of radiation protection and radiation therapy. However, biological effects in HLEC following protracted exposure have not yet fully been explored. Here, we investigated the temporal kinetics of DNA double-strand breaks (DSBs) and cell survival of HLEC after exposure to photon beams at various dose rates, compared to those of human lung fibroblasts (WI-38). In parallel, we quantified the recovery for DSB and cell survival using a biophysical model. The study revealed that HLEC cells have a lower repair rate than WI-38 cells. There is no significant impact of dose rate on cell survival in both cell lines in the dose-rate range of 0.033-1.82 Gy/min. On the other hand, the experimental residual DSBs showed inverse dose rate effects (IDREs) compared to the model prediction, highlighting the importance of the IDREs in evaluating radiation effects on the ocular lens.

Journal Articles

Calculation of DNA damage yields using PHITS; Challenge from macroscopic to microscopic simulation

Sato, Tatsuhiko

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 66(3), p.143 - 145, 2024/03

DNA damage calculation using the track-structure mode of PHITS will be summarized in this report.

Journal Articles

Changes in molecular conformation and electronic structure of DNA under $$^{12}$$C ions based on first-principles calculations

Sekikawa, Takuya; Matsuya, Yusuke; Hwang, B.*; Ishizaka, Masato*; Kawai, Hiroyuki*; Ono, Yoshiaki*; Sato, Tatsuhiko; Kai, Takeshi

Nuclear Instruments and Methods in Physics Research B, 548, p.165231_1 - 165231_6, 2024/03

 Times Cited Count:1 Percentile:63.95(Instruments & Instrumentation)

One of the main causes of radiation effects on the human body is thought to be damage to DNA, which carries genetic information. However, it is not fully understood what kind of molecular structural changes DNA undergoes upon radiation damage. Since it has been reported that various types of DNA damage are formed when DNA is irradiated, our group has investigated the relationship between DNA damage and various patterns of radiation-induced ionization induced by radiation. Although we have so far analyzed DNA damage in a simple system using a rigid body model of DNA, more detailed calculations are required to analyze the molecular structural changes in DNA, which are considered to be important in considering the effects on the human body. In this study, we attempted to clarify the molecular conformational changes of DNA using OpenMX, a first-principles calculation software that can discuss electronic states based on molecular structures. Specifically, we calculated the most stable structure, band dispersion, and wave function of DNA under the assumption that one and two electrons are ionized by various radiation. In the presentation, we will discuss the relationship between the energy dependence of each incident radiation type and the molecular conformational change of DNA. In addition, the radiation-induced changes in the basic physical properties of DNA (corresponding to the initial stage of DNA damage) will be discussed from the viewpoints of both radiation physics and solid state physics.

Journal Articles

System of radiological protection; Towards a consistent framework on earth and in space

R$"u$hm, W.*; Ban, Nobuhiko*; Chen, J.*; Li, C.*; Dobynde, M.*; Durante, M.*; El-Jaby, S.*; Komiyama, Tatsuto*; Ozasa, Kotaro*; Sato, Tatsuhiko; et al.

Journal of Medical Physics - Zeitschrift f$"u$r medizinische Physik -, 34(1), p.4 - 13, 2024/02

 Times Cited Count:0 Percentile:0.00(Radiology, Nuclear Medicine & Medical Imaging)

The International Commission on Radiological Protection (ICRP) provides independent recommendations on radiological protection for the public benefit. For more than 90 years, the ICRP System of Radiological Protection has been guiding the development and implementation of national and international standards and regulations on radiological protection. In 2019, ICRP established Task Group (TG) 115 to address a broader range of topics related to dose and risk assessment for radiological protection of astronauts. This paper gives an overview of the System of Radiological Protection and a brief summary of ICRP's work on radiological protection of astronauts.

559 (Records 1-20 displayed on this page)