@misc{oai:repo.qst.go.jp:00075611,
 author = {Chang, Weishan and Koba, Yusuke and Furuta, Takuya and Yonai, Shunsuke and Hasimoto, Shintaro and Matsumoto, Shinnosuke and Sato, Tatsuhiko and Chang, Weishan and Koba, Yusuke and Yonai, Shunsuke and Matsumoto, Shinnosuke},
 month = {Apr},
 note = {Purpose: Most treatment planning system (TPS) used in carbon-ion radiotherapy (CIRT) facilities are implemented with pencil beam algorithm which cannot compute dose by secondary particle and neutron dose to whole body while these dose are thought to be the reasons of radiation-induced secondary cancer.  In this work, we evaluated the CT conversion method and the accuracy of the beam modeling of a developing dedicated framework using Monte Carlo (MC) simulation code PHITS for retrospective analysis of CIRT.
Materials and methods: For consistency to the TPS, the CT number to stopping power ratio table used in TPS and the standard tissues of reference adult phantoms published in ICRP-110 were used to converse CT number to density and material composition.  To verify the conversion methods corresponding to the TPS, we calculated the depth dose distribution in ten different material by TPS and MC and compared the range.
A 400 MeV/n carbon beam with an 8 cm SOBP was used for verifying the beam model in MC.  Advanced Markus chamber and pin-point chamber were used for depth dose distribution and lateral dose distribution, respectively. In addition to dose distribution inside of field, the out-filed dose distribution was also compared in this work. 
Results: For all the range difference between TPS and MC are within 1 mm, while the dose difference are shown in some material with high CT number. The measured range agreed well with the range calculated by TPS and MC while significant dose difference in the fragmentation tail behind the Bragg peak was found when a relatively thick range shifter was implanted. 
Conclusion: In this work, the CT conversion method and the accuracy of the beam modeling of a developing dedicated framework for retrospective analysis of CIRT were evaluated., 第117回日本医学物理学会学術大会},
 title = {Development of a CT-number parameterization method and validation for Monte Carlo simulation of carbon-ion radiotherapy: A preliminary study},
 year = {2019}
}