Author(s)

Satoshi Yamaguchi^1*, Eiichi Sato², Ryuji Nakamura¹, Hirobumi Oikawa¹, Hisao Kakuhara¹, Koyo Kikuchi¹, Hisanori Ariga¹, Shigeru Ehara¹

¹Department of Radiology, School of Medicine, Iwate Medical University, Morioka, Japan.
²Department of Physics, Iwate Medical University, Morioka, Japan.

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.

Condenser Dosimeter, Disposable Mini-Substrate, Surface

Yamaguchi, S. , Sato, E. , Nakamura, R. , Oikawa, H. , Kakuhara, H. , Kikuchi, K. , Ariga, H. and Ehara, S. (2018) Disposable Condenser Dosimeter Using a Skin-Insulated Mini-Substrate with a Silicon X-Ray Diode in Image-Guided Radiation Therapy. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 7, 35-46. doi: 10.4236/ijmpcero.2018.71004.