放射治疗剂量核查用玻璃剂量计的剂量学特性

Dosimetric Properties of the Glass Dosimeters Used for Dose Auditing in Radiotherapy

[目的]为开展放射治疗剂量核查提供新手段,研究GD-301型玻璃剂量计的辐射剂量学特性。[方法]利用次级标准剂量学实验室的^(60)Coγ放射源,对5组GD-301型玻璃剂量计进行不同剂量的照射,分析其读出值的剂量线性、均匀性、重复性和衰退等剂量学参数。[结果]GD-301型玻璃剂量计在1～3Gy照射剂量范围内具有理想的剂量线性;5组剂量计测量值与其相应的参考照射量值的相对偏差为-0.06%～1.9%,各组剂量计的测量值分散性在0.4%～1.8%之间;玻璃剂量计在照射30d内,其辐射信号的衰退<0.9%。[结论]GD-301型玻璃剂量计的剂量线性和均匀性优良,可用于开展放射治疗设备输出量的核查。

[ Objective ] To study the dosimetric properties of GD-301 glass dosimeter to provide a new measure for dose auditing in radiotherapy. [ Methods ] Five groups of the glass dosimeters were irradiated with different levels of gamma exposure from a ^60Co source in a secondly standard dosimetry laboratory. Based on the readout values of the irradiated glass dosimeters, the dose linearity, uniformity and reproducibility of signal as well as the fading effect of the dosimeters were analyzed. [ Results ] The results showed that the dose linearity of GD-301 glass dosimeter was ideal from 1 Gy to 3 Gy of irradiation. The relative deviations between the measured and reference values ranged from -0.06% to 1.9% among the 5 groups of dosimeters, and the dispersion values among 6 different dosimeters in the same groups varied from 0.4% to 1.8%. The fading effect was less than 0.9% in 30 days after irradiation. [ Conclusion ] Both the dose linearity and the uniformity of the GD-301 glass dosimeter are fairly good, it can be used for dose auditing in radiotherapy.