加速器辐射质测量方法的比较分析

Comparative Analysis of Measurement Methods for Accelerator Radiation Quality

针对加速器高能光子辐射质的不同测量方法,在剂量比(D20/D10)通过公式计算法和组织模体比(TPR20,10)直接实验法的基础上,提出了定剂量率和定剂量的测量方法.在中国计量科学研究院加速器实验室分别对6 MV、10 MV、25 MV光子的辐射质进行测量.实验结果表明:在测量加速器辐射质时,采用定剂量法比定剂量率法不确定度明显变小;采用定剂量法时,6 MV、10 MV、25 MV采用公式法计算的值比实际测量值分别偏小0.27％、0.31％、0.35％,采用剂量率法进行修正后和此结果一致.

According to the different measurement methods of accelerator high-energy photon beams radiation quality,the dose ratio (D20/D10) calculated by the formula and the tissue phantom ratio (TPR20.a0) measured by direct experimental,measuring charge in a certain period of time or in a certain Monitor Units is proposed.The radiation quality of 6M-V,10MV and 25MV photon beams are measured respectively at the clinical linac laboratory in National Institute of Metrology(China).The results show that the uncertainty of accelerator high-energy photon beams radiation quality measured in a certain Monitor Units is obviously smaller than measured in a certain period of time,and the certain Monitor Units method of 6 MV,10 MV,25 MV using D20/D10 to calculate the value of the values of TPR20,10 were smaller than 0.27％,0.31％,0.35％.