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目的采用平板型电离室和热释光剂量计(TLD)胶囊进行放射治疗临床剂量学验证。方法 随机抽取江苏省5家开展肿瘤放射治疗医院的5台医用加速器,设置不同照射野和源皮距(SSD),加速器电子线标准照射剂量为2.000 Gy,分别采用平板型电离室和TLD方法验证电子线水下最大剂量点的吸收剂量。结果 平板型电离室与TLD验证方法的实测剂量(分别为Dchamber、DTLD)、实测剂量与标准照射剂量的相对偏差及其在±5.00%以外的发生率分别比较,差异均无统计学意义(P>0.05);DTLD与Dchamber的相对偏差为-2.23%～3.72%。照射野为10 cm×10 cm条件下,SSD分别为100、105、110 cm时,Dchamber与DTLD均随SSD增加呈下降趋势;SSD=110 cm时,Dchamber高于DTLD,差异有统计学意义(P<0.05)。结论 作为电子线剂量验证方法的补充,TLD验证方法准确可靠。但仍需要对不同SSD条件下的剂量特性作进一步研究。
OBJECTIVE: Radiation therapy clinical dosimetry was performed using a plate-type ionization chamber and a thermoluminescence dosimeter (TLD) capsule. Methods Five sets of medical accelerators were randomly selected from 5 cancer radiotherapy hospitals in Jiangsu Province to set different irradiation fields and source distance (SSD). The standard dose of accelerator electron beam was 2.000 Gy. The plate type ionization chamber and TLD method were used to verify Electronic wire underwater maximum dose point of absorbed dose. Results The measured doses (Dchamber, DTLD) of the plate-type ionization chamber and the TLD validation method showed no significant difference in the relative deviation between the measured dose and the standard radiation dose and the incidence outside ± 5.00% (P > 0.05). The relative deviation between DTLD and Dchamber was -2.23% ~ 3.72%. Dchamber and DTLD both decreased with the increase of SSD when the SSDs were 100, 105 and 110 cm, respectively, and the Dchamber was higher than DTLD at the SSD = 110 cm (10 cm × 10 cm) P <0.05). Conclusions TLD verification is accurate and reliable as a complement to electronic line dose verification. However, there is still a need for further investigation of the dose characteristics under different SSD conditions.