Development of whole-body dose assessment system for carbon ion radiotherapy; RT-PHITS for CIRT

Furuta, Takuya   

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.