Ishikawa Masayori, Nagase Naomi, Matsuura Taeko, Hiratsuka Junichi, Suzuki Ryusuke, Miyamoto Naoki, Sutherland Kenneth Lee, Fujita Katsuhisa, Shirato Hiroki
Department of Medical Physics and Engineering, Graduate School of Medicine, Hokkaido University, N-15 W-7 Kita-ku, Sapporo Hokkaido, 060-8638, Japan
Department of Radiology, Kawasaki Medical School Hospital, 577 Matsushima, Kurashiki Okayama, 701-0192, Japan.
J Radiat Res. 2015 Mar;56(2):372-81. doi: 10.1093/jrr/rru106. Epub 2015 Jan 23.
The scintillator with optical fiber (SOF) dosimeter consists of a miniature scintillator mounted on the tip of an optical fiber. The scintillator of the current SOF dosimeter is a 1-mm diameter hemisphere. For a scintillation dosimeter coupled with an optical fiber, measurement accuracy is influenced by signals due to Cerenkov radiation in the optical fiber. We have implemented a spectral filtering technique for compensating for the Cerenkov radiation effect specifically for our plastic scintillator-based dosimeter, using a wavelength-separated counting method. A dichroic mirror was used for separating input light signals. Individual signal counting was performed for high- and low-wavelength light signals. To confirm the accuracy, measurements with various amounts of Cerenkov radiation were performed by changing the incident direction while keeping the Ir-192 source-to-dosimeter distance constant, resulting in a fluctuation of <5%. Optical fiber bending was also addressed; no bending effect was observed for our wavelength-separated SOF dosimeter.
带有光纤的闪烁体（SOF）剂量计由安装在光纤末端的微型闪烁体组成。当前SOF剂量计的闪烁体是直径为1毫米的半球体。对于与光纤耦合的闪烁剂量计，测量精度会受到光纤中切伦科夫辐射产生的信号的影响。我们已经实施了一种光谱滤波技术，具体针对我们基于塑料闪烁体的剂量计，采用波长分离计数法来补偿切伦科夫辐射效应。使用二向色镜分离输入光信号。对高波长和低波长光信号进行单独的信号计数。为了确认准确性，在保持铱 - 192源到剂量计距离不变的情况下，通过改变入射方向进行了不同量切伦科夫辐射的测量，结果波动小于5%。还研究了光纤弯曲情况；对于我们的波长分离SOF剂量计，未观察到弯曲效应。
