数字化晨检仪的研制

Development of the Digital Morning Check Device

目的研制用于直线加速器输出量晨检的数字化晨检仪。方法采用单个平板电离室作为探测器,与PIC16F877单片机处理器等构成数字化检测系统。按照JJG912-2010对治疗型电离室剂量检定的要求,在直线加速器下进行输出剂量测量,对系统的剂量学特性进行测试。结果在常规的跳数检测范围内(50~400 MU),晨检仪的测量剂量线性较好,线性拟合的相关系数均近似为1,最大偏差为0.4%。单次测量中,其测量重复性的最大偏差好于0.3%。对于不同剂量率的响应,其最大偏差小于0.3%。在半年检测过程中,其稳定性好于1%。结论研制晨检仪的剂量特性符合JJG912-2010《治疗水平电离室剂量计》的要求,可用于直线加速器输出量的晨检。

Objective To develop a digital device for measuring the dose output of medical accelerator in the morning check. Methods It was constructed by a single tablet ionization chamber and PIC16F877 single chip processor. The measurement of output dose under the medical accelerator was performed according to the document of JJG912-2010, and the dosimetry characteristics of the medical accelerator was tested by morning check device. Results In the range of 50～400 MU, the measured dose was linear.The correlation coefficients of linear fitting were approximately 1.00 and the maximum deviation was smaller than 0.4%. In a single measurement, the maximum deviation of measurement repeatability was better than 0.3%. The maximum deviation was less than 0.3% for different dose rates. In the long-term (half-year) testing process, the reproducibility of device was better than 1%. Conclusion Dosimetry characteristics of the device can meet the requirements of JJG912-2010 Verification Regulation of Ion Chamber Dosimeters Used in Radiotherapy. The research and development of the device can be used to measure the relative dose of the Linac in daily tests.