上海市16台医用电子加速器输出量的质量控制

[目的]了解上海市放射治疗医用电子加速器输出量的质量控制水平。[方法]将核查用的剂量计置于30cm×30cm×30cm水模体的水面下5cm中心处，在源点距水面100cm、照射野10cm×10cm的条件下，给予约2Gy吸收剂量的照射；计算所给予剂量与剂量计测量值的相对偏差。相对偏差≤土5％为合格。[结果]所调查的16台医用电子加速器，其预设剂量与实测剂量的相对偏差范围为-6．8％～8．1％，总合格率为87．5％。有2台机器的相对偏差超过±5％。[结论]上海市放射治疗医用电子加速器输出量合格率的总体情况良好，但仍需要加强对放射治疗技术人员的业务素质培训和监督核查。

Quality Control of Radiation Output of 16 Medical Accelerators in Shanghai

[ Objective ] To investigate the current status of dose control for radiotherapy dosimetry in Shanghai. [ Methods ] Having set the dosimeters at the central point of a field which was 5 cm beneath the surface of a water phantom（ 30cm×30cm×30cm ）, irradiate the dosimeters with an absorbed dose of about 2Gy from a source at a distance of 100cm above the Water surface with an exposure field of 10 cm ×10 cm. Calculate the relative deviation between the stated dose and measured ones, and judge the quality with a deviation limit of ＋ 5%. [ Results ] The deviations ranged from -6.8% to 8.1% among the 16 measurements, 87.5% of the accelerators passed the auditing. Even though 2 of the accelerators did not pass the quality test, their deviations were still less than 10%. [ Conclusion ] The current quality status of radiotherapy dosimetry is fairly good in Shanghai. However, further training of the technicians and auditing rules are still needed to be strengthened.