Development of the DICOM-based Monte Carlo dose reconstruction system for a retrospective study on the secondary cancer risk in carbon ion radiotherapy

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

https://doi.org/10.1088/1361-6560/ac7998

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.

Technical Note: Validation of a material assignment method for a retrospective study of carbon-ion radiotherapy using Monte Carlo simulation

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

https://doi.org/10.1093/jrr/rrab028

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.

Application of an augmentation method to MCR-ALS analysis for XAFS and Raman data matrices in the structural change of isopolymolybdates

Saeki, Morihisa*; Yomogida, Takumi; Matsumura, Daiju; Saito, Takumi*; Nakanishi, Ryuzo*; Tsuji, Takuya; Oba, Hironori*

Analytical Sciences, 36(11), p.1371 - 1378, 2020/11

https://doi.org/10.2116/analsci.20P147

We measured X-ray absorption fine structure (XAFS) and Raman spectra of isopolymolybdates(VI) in HNO solution (0.15- 4.0 M), which change their geometries depending on acid concentration, and performed simultaneous resolution of the XAFS and Raman data using a multivariate curve resolution by alternating least-squares (MCR-ALS) analysis. In iterative ALS optimization, initial data matrices were prepared by two different methods. The MCR-ALS result of single XAFS data matrix shows large dependence on the preparation method of the initial data matrices. The MCR-ALS result of an augmented matrix of Raman and XAFS data has little dependence on the initial data matrices. It indicates that the augmentation method effectively improves the rotation ambiguities in the MCR-ALS analysis of the XAFS data. Based on the model fitting of the pure EXAFS oscillations, we revealed the change of [MoO(HO)] [MoO(HO)] [HMoO(HO)] in the highly concentrated HNO solution.

In Situ Time-Resolved XAFS Studies on Laser-induced Particle Formation of Palladium Metal in an Aqueous/EtOH solution

Saeki, Morihisa*; Matsumura, Daiju; Yomogida, Takumi; Taguchi, Tomitsugu*; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*

Journal of Physical Chemistry C, 123(1), p.817 - 824, 2019/01

https://doi.org/10.1021/acs.jpcc.8b09532

Reaction kinetics of laser-induced particle formation in an aqueous solution of PdCl was investigated by transmission electron microscope (TEM) and dispersive X-ray absorption fine structure (DXAFS). The Pd particle was generated by irradiation of nanosecond pulsed 266-nm laser. The TEM observation showed dependence of the particle size on the laser fluence and promotion of the particle growth by irradiation of high-fluence laser. The DXAFS data give us the Pd concentration. Temporal changes of the Pd concentration analyzed based on Finke-Watzky two step mechanism. The analysis elucidates that the laser photon contributes to the reduction of the PdCl ion by the one-photon process and to the autocatalytic growth of the Pd particles by the multi-photon process.

Japan - IAEA Joint Nuclear Energy Management School 2016

Yamaguchi, Mika; Hidaka, Akihide; Ikuta, Yuko; Murakami, Kenta*; Tomita, Akira*; Hirose, Hiroya*; Watanebe, Masanori*; Ueda, Kinichi*; Namaizawa, Ken*; Onose, Takatoshi*; et al.

JAEA-Review 2017-002, 60 Pages, 2017/03

JAEA-Review-2017-002.pdf:9.41MB

Since 2010, IAEA has held the NEM School to develop future leaders who plan and manage nuclear energy utilization in their county. Since 2012, JAEA together with Japan Nuclear HRD Network, University of Tokyo, Japan Atomic Industrial Forum and JAIF International Cooperation Center have cohosted the school in Japan in cooperation with IAEA. Since then, the school has been held in Japan every year. In 2006, Japanese nuclear technology and experience, such as lessons learned from the Fukushima Daiichi Nuclear Power Plant accident, were provided to offer a unique opportunity for the participants to learn about particular cases in Japan. Through the school, we contributed to the internationalization of Japanese young nuclear professionals, development of nuclear human resource of other countries including nuclear newcomers, and enhanced cooperative relationship with IAEA. Additionally, collaborative relationship within the network was strengthened by organizing the school in Japan.

Study on decommissioning of water loop irradiation facility and classification of waste

Onuma, Yuichi; Ishida, Takuya; Sakata, Ikuma*; Kodaira, Akira*; Sakai, Jun*; Oba, Seiichiro*; Kanno, Masaru; Saito, Takashi; Kinase, Muneyuki*; Ishitsuka, Etsuo

JAEA-Technology 2008-078, 39 Pages, 2008/12

JAEA-Technology-2008-078.pdf:13.42MB

Decommissioning of the water loop irradiation facility polluted by fission products and cruds was studied, and the reasonable waste classification occurring by the decommissioning was also studied. A out-pile equipment of the irradiation loop facility installed in JMTR is considered as a decommissioning object. Measurement of ambient dose rate in the out-pile facility and evaluation of the deposited radionuclide concentration in the cooling pipe were carried. In result, it was clear that the significant radionuclide is Co, and that occurred waste can classify as the shallow-ground trench disposal level, clearance level, non-radioactive waste. Furthermore, through the investigation of the cutting method for minimizing secondary waste generation, plumbing cutting machine with preventing scattering function was developed by trial manufactured cutter that surrounds the cutting pipe by box.

Neutron diffraction studies on the martensite phase and intermediate phase of NiMnGa alloy crystal

Kushida, Hiroaki*; Fukuda, Kodai*; Terai, Tomoyuki*; Fukuda, Takashi*; Kakeshita, Tomoyuki*; Oba, Takuya*; Osakabe, Toyotaka; Kakurai, Kazuhisa

no journal, , 

no abstracts in English

Spatial control of fast molecular/cluster-ion beams with capillaries

Tsuchida, Hidetsugu*; Majima, Takuya*; Tomita, Shigeo*; Sasa, Kimikazu*; Hirata, Koichi*; Shibata, Hiromi*; Saito, Yuichi; Narumi, Kazumasa; Chiba, Atsuya; Yamada, Keisuke; et al.

no journal, , 

no abstracts in English

XAFS study on effect of molybdenum addition on photo-induced particle formation of palladium

Saeki, Morihisa; Matsumura, Daiju; Yomogida, Takumi; Taguchi, Tomitsugu; Tsuji, Takuya; Kusano, Shogo*; Miyazaki, Tatsuya*; Takao, Koichiro*; Oba, Hironori; Nakashima, Nobuaki*

no journal, , 

no abstracts in English

Time-resolved XAFS studies on laser-induced particle formation of palladium ions in aqueous solution

Saeki, Morihisa*; Matsumura, Daiju; Tsuji, Takuya; Yomogida, Takumi; Taguchi, Tomitsugu*; Oba, Hironori*

no journal, , 

Irradiation of a nanosecond pulsed UV laser into a solution of palladium ion leads to formation of palladium particles with submicron size (100-800 nm). We investigate formation mechanism of the submicron size particles by time-resolved X-ray absorption fine structure (XAFS) spectroscopy.