Paul J M, Koch R F, Philip P C
Med Phys. 1985 Jul-Aug;12(4):424-30. doi: 10.1118/1.595704.
The AAPM Task Group 21 protocol is the latest amongst the protocols introduced in recent years covering the dosimetry of high-energy x-ray and electron beams used in radiotherapy. We have found that the C lambda value for 15-MV x rays requires 1.6% upward adjustment, whereas the CE values for electrons in the range 7-18 MeV require downward adjustment of 1%-3% compared to our previous values. The adjustment values given in this paper pertain to the specific measuring systems and high-energy beams considered here and would not necessarily be applicable to other systems. The dose to medium, calculated for different modalities, was verified by thermoluminescent dosimetry and the results were found to be consistent. These values of C lambda and CE have also been compared with those derived using other protocols, particularly the Nordic Association of Clinical Physics 80 and 81, and the discrepancies discussed.
美国医学物理师协会任务组21协议是近年来推出的涵盖放射治疗中使用的高能X射线和电子束剂量测定的协议中最新的一个。我们发现，15兆伏X射线的Cλ值需要向上调整1.6%，而7-18兆电子伏特范围内电子的CE值与我们之前的值相比需要向下调整1%-3%。本文给出的调整值适用于这里所考虑的特定测量系统和高能束，不一定适用于其他系统。通过热释光剂量测定法验证了针对不同模式计算的介质剂量，结果是一致的。还将这些Cλ和CE值与使用其他协议（特别是北欧临床物理协会80和81）得出的值进行了比较，并讨论了差异。
