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.

Dissolved radiocaesium in seawater off the coast of Fukushima during 2013-2015

Fukuda, Miho*; Aono, Tatsuo*; Yamazaki, Shinnosuke*; Nishikawa, Jun*; Otosaka, Shigeyoshi; Ishimaru, Takashi*; Kanda, Jota*

Journal of Radioanalytical and Nuclear Chemistry, 311(2), p.1479 - 1484, 2017/02

https://doi.org/10.1007/s10967-016-5009-9

In order to investigate processes affecting distribution of radiocaesium in seawater in the adjacent region of Fukushima Daiichi Nuclear Power Plant (FDNPP), relationships between Cs activity in seawater and physical properties of seawater (salinity, temperature, and potential density) were observed in seven stations within 10 km radius from the FDNPP. As a whole, Cs concentrations in seawater were higher in the vicinity of the FDNPP, and were negatively correlated with potential density. From these results, it can be considered that river water discharge or export of seawater from the FDNPP's harbor has affected the higher activity levels of Cs in seawater. It was also observed that the Cs-elevated seawater can be advected to the 2050 m depths.

Applications and imaging techniques of a Si/CdTe Compton -ray camera

Takeda, Shinichiro*; Ichinohe, Yuto*; Hagino, Koichi*; Odaka, Hirokazu*; Yuasa, Takayuki*; Ishikawa, Shinnosuke*; Fukuyama, Taro*; Saito, Shinya*; Sato, Tamotsu*; Sato, Goro*; et al.

Physics Procedia, 37, p.859 - 866, 2012/10

https://doi.org/10.1016/j.phpro.2012.04.096

By using new Compton camera consisting of silicon double-sided strip detector (Si-DSD) and CdTe-DSD developed for the ASTRO-H mission, an experiment was conducted to study its feasibility for advanced hotspot monitoring. In addition to hotspot imaging already provided by commercial imaging systems, the identification of the variety of radioisotopes is realized thanks to the good energy resolution given by the semiconductor detectors. Three radioisotopes of Ba (356 keV), Na (511 keV) and Cs (662 keV) were individually imaged by applying event selection in the energy window and the -ray images was correctly overlapped by an optical picture. The detection efficiency of 1.6810 (effective area: 1.710 cm) and angular resolution of 3.8 were obtained by stacking five detector modules for 662 keV -ray. The higher detection efficiency required in a specific use can be achieved by stacking more detector modules.

Development of head module for multi-head Si/CdTe Compton camera for medical applications

Yamaguchi, Mitsutaka; Kawachi, Naoki; Suzui, Nobuo; Fujimaki, Shu; Kamiya, Tomihiro; Odaka, Hirokazu*; Ishikawa, Shinnosuke*; Kokubun, Motohide*; Watanabe, Shin*; Takahashi, Tadayuki*; et al.

Nuclear Instruments and Methods in Physics Research A, 648(Suppl.1), p.S2 - S7, 2011/08

https://doi.org/10.1016/j.nima.2011.02.040

We are constructing a three-dimensional imaging system for medical and biological applications. The system will allow simultaneous imaging at high spatial and energy resolutions across a wide energy range, from several tens of keV to a few MeV. In this work, one prototype head module have been developed for a multi-head Si/CdTe Compton camera system. The performance of the prototype was evaluated with a sealed Ba-133 radiation source. The experiments confirmed that the imaging results were consistent with actual source position. In addition to the resolution for the parallel directions to the detector surface, the position resolution was evaluated for the depth direction at a point in near region of the head-module. These position resolutions were well reproduced by Monte Carlo simulation results.

Experimental results of the -ray imaging capability with a Si/CdTe semiconductor Compton camera

Takeda, Shinichiro*; Aono, Hiroyuki*; Okuyama, Sho*; Ishikawa, Shinnosuke*; Odaka, Hirokazu*; Watanabe, Shin*; Kokubun, Motohide*; Takahashi, Tadayuki*; Nakazawa, Kazuhiro*; Tajima, Hiroyasu*; et al.

IEEE Transactions on Nuclear Science, 56(3), p.783 - 790, 2009/06

https://doi.org/10.1109/TNS.2008.2012059

Basic characteristics of a newly developed Si/CdTe Compton camera for medical imaging

Kawachi, Naoki; Watanabe, Shigeki; Sato, Takahiro; Arakawa, Kazuo; Takeda, Shinichiro*; Ishikawa, Shinnosuke*; Aono, Hiroyuki*; Watanabe, Shin*; Yamaguchi, Mitsutaka*; Takahashi, Tadayuki*; et al.

2008 IEEE Nuclear Science Symposium Conference Record (CD-ROM), p.1540 - 1543, 2008/10

Study of spatial resolution of multi-head Si/CdTe Compton camera for medical application

Yamaguchi, Mitsutaka; Kawachi, Naoki; Watanabe, Shigeki; Sato, Takahiro; Arakawa, Kazuo; Kojima, Takuji; Kamiya, Tomihiro; Watanabe, Shin*; Takeda, Shinichiro*; Odaka, Hirokazu*; et al.

no journal, , 

no abstracts in English

Development of a head module for multi-head Si/CdTe Compton camera

Yamaguchi, Mitsutaka; Kamiya, Tomihiro; Kawachi, Naoki; Suzui, Nobuo; Ishioka, Noriko; Fujimaki, Shu; Watanabe, Shin*; Ishikawa, Shinnosuke*; Odaka, Hirokazu*; Kokubun, Motohide*; et al.

no journal, , 

no abstracts in English

Substantiative experiments of distortion correction for novel Si/CdTe Compton camera

Kawachi, Naoki; Yamaguchi, Mitsutaka; Nagao, Yuto; Suzui, Nobuo; Fujimaki, Shu; Kamiya, Tomihiro; Odaka, Hirokazu*; Kokubun, Motohide*; Takeda, Shinichiro*; Ishikawa, Shinnosuke*; et al.

no journal, , 

Image analysis with Monte Carlo simulation of multi-head Si/CdTe Compton camera for medical imaging

Yamaguchi, Mitsutaka*; Kawachi, Naoki; Watanabe, Shin*; Odaka, Hirokazu*; Takeda, Shinichiro*; Ishikawa, Shinnosuke*; Aono, Hiroyuki*; Takahashi, Tadayuki*; Arakawa, Kazuo; Nakano, Takashi*

no journal, , 

no abstracts in English