[19p-N304-2~7] Forefront of Quantum Beam Application - Current Status and Future Prospects of Medical and Industrial Use -

[19p-N304-2] Dose response of a miniature spherical solar cells for therapeutic carbon-ion beam

〇Naruhiro Matsufuji¹, Yusuke Koba¹, Toshiyuki Shirai¹, Hiroyuki Kikuchi², Josuke Nakata² (1.QST, 2.Sphelar Power Co.)

Keywords:solar cell, ion-beam therapy, dosimeter

As the best use of the Bragg curve nature, hypofractionated ion-beam therapy has been promoted on various tumor site. In carbon-ion therapy for prostate cancer treatment at the Heavy Ion Medical Accelerator in Chiba (HIMAC) of QST, radical hypofractionation has been performed by selectively reducing the urethral dose located at the center of the prostate tumor. It is needed there to establish an in-vivo in-situ dosimeter to confirm if the dose to urethra is surely reduced as planned during the therapeutic irradiation. This study investigated a response of a miniature sphere diode (solar cell) to serve as the in-vivo in-situ dosimeter for therapeutic carbon-ion beam.
Soral cell of 1.2 and 1.8mm in diameter made by Sphelar Power Co., Ltd. (Kyoto, Japan) was tested in the study. The solar cell showed decrease in sensitivity of about 1% / Gy but well corrected as a function of integral dose. The output linearity on dose and subtle incident angular dependence together with the smallness and safeness make the solar cell as a good candidate for the in-vivo in-situ dosimeter in ion-beam therapy.