TITLE:
Disposable Condenser Dosimeter Using a Skin-Insulated Mini-Substrate with a Silicon X-Ray Diode in Image-Guided Radiation Therapy
AUTHORS:
Satoshi Yamaguchi, Eiichi Sato, Ryuji Nakamura, Hirobumi Oikawa, Hisao Kakuhara, Koyo Kikuchi, Hisanori Ariga, Shigeru Ehara
KEYWORDS:
Condenser Dosimeter, Disposable Mini-Substrate, Surface
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.7 No.1,
February
13,
2018
ABSTRACT: To measure integral doses in image-guided radiation
therapy, we developed a disposable mini-substrate with a 1.0-μF condenser and a
silicon X-ray diode (Si-XD). The Si-XD is a high-sensitivity photodiode
selected for detecting X-rays. In the substrate with dimensions of 15 × 15 mm2, the initial
charging voltage is 3.30 V, and the charging voltage is decreased by
photocurrents flowing through the Si-XD during X-ray exposing. The condenser in
the substrate is charged by a microcomputer dock, and the charging voltage is
also measured using an analog to digital converter in the dock after exposing
X-rays. The dock is connected to a personal computer through a USB cable, and
integral doses are shown on the PC monitor. The doses were proportional to
decreases in the charging voltage, and the calibrated doses corresponded well to
those obtained using a readily available ionization chamber.