@misc{oai:repo.qst.go.jp:00083871,
 author = {Shunsuke, Yonai and Naoya, Saotome and Makoto, Sakama and Nobuyuki, Kanematsu and Shunsuke, Yonai and Naoya, Saotome and Makoto, Sakama and Nobuyuki, Kanematsu},
 month = {Jun},
 note = {The QST hospital has successfully treated more than 200 patients with choroidal melanoma by broad beam carbon ion radiotherapy (CIRT) with a compensator and a patient-specific collimator since 2001. We decided in 2017 to use scanning carbon ion beam with a rotating gantry for this treatment owing to its flexibilities of dose conformation and beam direction, and then its clinical trial started in April, 2018.
In our facility, a commercial 2D ionization chamber array had been employed to verify the 2D dose distribution for any patient specific QA. [1] However, the target volume in choroidal melanoma treatment is typically so small that the 2D array is not appropriate to the verification tool of 2D dose distribution due to its low spatial resolution. Thus, in this clinical trial, we applied new method to the patient specific QA. The method consists of two dosimetric verifications by measurements of depth dose distribution with the Bragg peak chamber and lateral dose distributions at three different depths with the pinpoint chambers, and a verification of beam position at each beam spot with the existing beam position monitor (multi-wire proportional chamber). This method was successfully applied to patient specific QAs for 44 treatment beams of all 22 patients received scanning CIRT for choroidal melanoma in this clinical trial until July, 2019. Here, we provide the summary of the QA results and introduce the current QA procedure based on this clinical trial.
 [1] T. Furukawa et al., Med. Phys., 40, 121707 (2013)., The 59th Annual Conference of the Particle Therapy Co-Operative Group (PTCOG59)},
 title = {Patient specific QA of scanning beam carbon ion radiotherapy with rotating gantry for choroidal melanoma in clinical trial},
 year = {2021}
}