Fukui Yusuke, Hamada Yuto, Noma Kazuo, Harada Naoki
Radiology Service, Shiga University of Medical Science Hospital.
Radiology Service, Shiga University of Medical Science Hospital (Current address: Canon Medical Systems Corporation).
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2019;75(7):652-658. doi: 10.6009/jjrt.2019_JSRT_75.7.652.
Some radiation detectors are used for quality assurance and measured to radiation dose for high precision external beam radiotherapy. Recently, plastic scintillation detectors for MeV X-ray measurement are commercially released. The purpose of this study was to evaluate the performance of a commercial plastic scintillation detector with respect to the dose linearity, dose rate dependence, and the output coefficient compared the ionization chamber and the semiconductor detector using each different X-ray energy with or without flattening filter. The result that the dose linearity of each detector showed a linear response in any detectors. Dose rate dependence of plastic scintillation detector was increased when setting dose rate was changed, especially setting to low dose rate. The output coefficient of plastic scintillation detector was equivalent as that of the semiconductor detector even in smallest irradiation field. In conclusion, it was suggested that the plastic scintillation detector is a suitable detector in dose verification measurements for high precision external beam radiotherapy, although we must be with care to low dose rate measurements.
一些辐射探测器用于质量保证，并用于高精度外照射放疗的辐射剂量测量。最近，用于兆电子伏特X射线测量的塑料闪烁探测器已商业化发布。本研究的目的是评估一种商用塑料闪烁探测器在剂量线性、剂量率依赖性以及与电离室和半导体探测器相比的输出系数方面的性能，使用不同的X射线能量，有无均整滤过器。结果表明，每个探测器的剂量线性在任何探测器中均呈现线性响应。当设定剂量率改变时，尤其是设定为低剂量率时，塑料闪烁探测器的剂量率依赖性增加。即使在最小照射野中，塑料闪烁探测器的输出系数也与半导体探测器相当。总之，尽管在低剂量率测量时必须小心，但建议塑料闪烁探测器是高精度外照射放疗剂量验证测量中的合适探测器。
