Araki Fujio, Ikegami Tohru, Ishidoya Tatsuyo, Kubo Hideo D
Department of Radiological Technology, Kumamoto University College of Medical Science, Kumamoto 862-0976, Japan.
Med Phys. 2003 Aug;30(8):1976-81. doi: 10.1118/1.1587451.
A radiophotoluminescent (RPL) glass rod dosimeter (GRD) and a small active volume p-type silicon diode detector are used for the measurement of the output factors from Gamma-Knife fields. The GRD system consists of small rod-shaped glass chip detectors and an automatic readout device. The output factors measured with the GRD from the 14, 8 and 4 mm helmets relative to the 18 mm helmet are 0.981, 0.942 and 0.877, respectively. Similarly, the corresponding output factors measured with the p-type silicon diode detector are 0.980, 0.949 and 0.867, respectively. The output factors are corrected for the end effect for each helmet. The output factors obtained from both detectors are in good agreement with the values in a recent publication and the values recommended by Elekta, the manufacturer. The directional dependence of these detectors is also measured. For the Gamma-Knife angle ranging from 6 to 36 degrees in the y-z plane of the stereotactic space, the measured angular dependence of the GRD is approximately 1.0% at a 4 MV x-ray beam. The response of the silicon diode detector indicates approximately 3-4% directional dependence for the same angular range for a 6 MV x-ray beam. The Gamma-Knife helmet output factors measured with the silicon diode detector are corrected for angular dependence.
一种放射性光致发光（RPL）玻璃棒剂量计（GRD）和一个小有效体积的p型硅二极管探测器被用于测量伽玛刀射野的输出因子。GRD系统由小棒状玻璃芯片探测器和一个自动读出装置组成。用GRD测量的相对于18mm头盔，14mm、8mm和4mm头盔的输出因子分别为0.981、0.942和0.877。同样，用p型硅二极管探测器测量的相应输出因子分别为0.980、0.949和0.867。对每个头盔的输出因子进行了端部效应校正。从两个探测器获得的输出因子与最近一篇出版物中的值以及制造商Elekta推荐的值非常一致。还测量了这些探测器的方向依赖性。对于立体定向空间y-z平面中6至36度的伽玛刀角度，在4MV X射线束下，GRD测量的角度依赖性约为1.0%。对于6MV X射线束，在相同角度范围内，硅二极管探测器的响应表明方向依赖性约为3-4%。用硅二极管探测器测量的伽玛刀头盔输出因子进行了角度依赖性校正。
