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Furuta, Takuya
Isotope News, (787), p.20 - 23, 2023/06
Carbon ion radiotherapy has an advantage over conventional radiotherapy such that its superior dose concentration on the tumor helps to reduce unwanted dose to surrounding normal tissues. Nevertheless, a little dose to normal tissues, which is a potential risk of secondary cancer, is still unavoidable. In the current dose assessment, however, only assessment around target volume is performed for the tumor control and prevention of acute radiation injury of fatal organs. We therefore developed a system called RT-PHITS for CIRT to reproduce the carbon ion radiotherapy including the production and transport of secondary particles based on treatment planning data using PHITS. Using this system, whole-body dose assessment of patients in the past carbon ion radiotherapy can be performed. By comparing the dose assessment to the epidemiologic records of the patients, the relation between dose exposure of non-target organs and incidence of side effects such as secondary cancer will be elucidated.
Furuta, Takuya; Koba, Yusuke*; Hashimoto, Shintaro; Chang, W.*; Yonai, Shunsuke*; Matsumoto, Shinnosuke*; Ishikawa, Akihisa*; Sato, Tatsuhiko
Physics in Medicine & Biology, 67(14), p.145002_1 - 145002_15, 2022/07
Times Cited Count：3 Percentile：44.25(Engineering, Biomedical)Carbon ion radiotherapy has an advantage over conventional radiotherapy such that its superior dose concentration on the tumor helps to reduce unwanted dose to surrounding normal tissues. Nevertheless, a little dose to normal tissues, which is a potential risk of secondary cancer, is still unavoidable. The Monte Carlo simulation is a good candidate for the tool to assess secondary cancer risk, including the contributions of secondary particles produced by nuclear reactions. We therefore developed a new dose reconstruction system implementing PHITS as the engine. In this system, the PHITS input is automatically created from the DICOM data sets recorded in the treatment planning. The developed system was validated by comparing to experimental dose distribution in water and treatment plan on an anthropomorphic phantom. This system will be used for retrospective studies using the patient data in National Institute for Quantum and Science and Technology.
Chang, W.*; Koba, Yusuke*; Furuta, Takuya; Yonai, Shunsuke*; Hashimoto, Shintaro; Matsumoto, Shinnosuke*; Sato, Tatsuhiko
Journal of Radiation Research (Internet), 62(5), p.846 - 855, 2021/09
Times Cited Count：3 Percentile：25.1(Biology)With the aim of developing a revaluation tool of treatment plan in carbon-ion radiotherapy using Monte Carlo (MC) simulation, we propose two methods; one is dedicated to identify realistic-tissue materials from a CT image with satisfying the well-calibrated relationship between CT numbers and stopping power ratio (SPR) provided by TPS, and the other is to estimate dose to water considering the particle- and energy-dependent SPR between realistic tissue materials and water. We validated these proposed methods by computing depth dose distribution in homogeneous and heterogeneous phantoms composed of human tissue materials and water irradiated by a 400 MeV/u carbon beam with 8 cm SOBP using a MC simulation code PHITS and comparing with results of conventional treatment planning system (TPS). Our result suggested that use of water as a surrogate of real tissue materials, which is adopted in conventional TPS, is inadequate for dose estimation from secondary particles because their production rates cannot be scaled by SPR of the primary particle in water. We therefore concluded that the proposed methods can play important roles in the reevaluation of the treatment plans in carbon-ion radiotherapy.
Okumura, Keisuke
Fission Product Behavior under Severe Accident, p.116 - 121, 2021/05
no abstracts in English
Malins, A.; Machida, Masahiko; Vu, TheDang; Aizawa, Kazuya; Ishida, Takekazu*
Nuclear Instruments and Methods in Physics Research A, 953, p.163130_1 - 163130_7, 2020/02
Times Cited Count：6 Percentile：59.94(Instruments & Instrumentation)Mohammadi, A.*; Kinase, Sakae; Safavi-Naeini, M.*
Computational Anatomical Animal Models; Methodological Developments and Research Applications, p.3_1 - 3_27, 2018/12
Times Cited Count：0 Percentile：0.04(Anatomy & Morphology)Ozu, Akira; Komeda, Masao; Kureta, Masatoshi; Nakatsuka, Yoshiaki; Nakashima, Shinichi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 59(12), p.700 - 704, 2017/12
no abstracts in English
Hamamatsu, Kiyotaka; Takizuka, Tomonori; Hayashi, Nobuhiko; Ozeki, Takahisa
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
no abstracts in English
Malins, A.; Imamura, Naohiro*; Niizato, Tadafumi; Kim, M.; Sakuma, Kazuyuki; Shinomiya, Yoshiki*; Miura, Satoru*; Machida, Masahiko
no journal, ,
Kai, Takeshi; Matsuya, Yusuke; Sato, Tatsuhiko
no journal, ,
It has been found that the repair efficiency of DNA damage was extremely low for simultaneous damage within a few nm. The complex damage has been implicated in inducing harmful biological effects. However, such damage is hard to detect using experimental techniques. In our works, a dynamic Monte Carlo code (DMCC) has been developed to predict radiation DNA damage. From the results, we could predict the complex DNA damage formation composed of oxidative damage and reductive damage. The DMCC was partially implemented into PHITS [2] to simulate the electron track structure. The implementation made DNA damage prediction possible by the track structure mode. In this presentation, we explain the DMCC, and current states for development of track structure mode in PHITS. We discuss DNA damage formation and yield using the DMCC and the track structure mode.
Sato, Tetsuya; Nagame, Yuichiro*; Eichler, R.*
no journal, ,
Element 103, lawrencium (Lr) has been pointed out that it might have significantly high volatility more than that of lutetium (Lu), the lanthanide homolog of Lr, owing to an influence of the strong relativistic effect. In our previous work, we have measured the first ionization potential of Lr by using the surface ionization method. In the method, the Lr atom was surface ionized on a tantalum surface at a high temperature. If the surface temperature is sufficiently high, the ionization efficiency of Lr can be estimated by the Saha-Langmuir (S-L) equation. However, an adsorption loss of the atoms of interest onto the metal surface could be inevitable at a low temperature. In that case, the apparent ionization efficiency would become smaller than the value predicted from the S-L equation. We have developed a Monte Carlo simulation code to estimate the adsorption loss of atoms on the ion-source surface in this work. The simulation code describes the ionization behavior of the atoms by combining the thermal ionization process in the ionizer and the adsorption-desorption process on the surface.
Watanabe, Yuki; Hosomi, Kenji; Kaneko, Junichi*; Arai, Tomohiro*; Takada, Chie
no journal, ,
no abstracts in English
Yamamoto, Kazuyoshi; Xu, P. G.; Iwamoto, Chihiro*; Takamura, Masato*; Otake, Yoshie*; Shobu, Takahisa
no journal, ,
no abstracts in English
Ishikawa, Akihisa*; Koba, Yusuke*; Furuta, Takuya; Chang, W.*; Hashimoto, Shintaro; Yonai, Shunsuke*; Matsumoto, Shinnosuke*; Sato, Tatsuhiko
no journal, ,
There found to be a relationship between the dose-averaged linear energy transfer LETd and local tumor control in carbon-ion radiotherapy (CIRT). However, only physical dose and biological dose are registered in the past treatment records of CIRT in QST hospital and LETd can not be deduced directly. There is a method to estimate LETd based on RBE-LETd-fitted function but some problems such as non-singularity at the end point of carbon ions are known. On the other hand, we propose a method to reproduce the CIRT by reconstructing the beam transport geometry based on the treatment planning data and conduct Monte Carlo simulation. The LETd can be also computed directly. We therefore compared LETd obtained by Monte Carlo simulation with estimated LETd using the treatment planning data. We found that underestimation around the end point of carbon ions but the influence was local and thus the LETd estimates are valid for the purpose computing in organ scale.
Watanabe, Yuki; Hosomi, Kenji; Kawasaki, Kohei*; Ezaki, Iwao*; Takada, Chie
no journal, ,
no abstracts in English
