Williamson J F, Morin R L, Khan F M
Med Phys. 1983 Mar-Apr;10(2):135-40. doi: 10.1118/1.595234.
It is well known that the dose calibrator response/unit exposure rate depends significantly upon source energy. However, investigation of 137Cs, 192Ir, and 226Ra brachytherapy sources by empirical, analytical, and Monte Carlo techniques shows that source filtration significantly affects the calibrator reading to exposure rate conversion factor. The results demonstrate that for each clinically used filtration thickness an exposure calibrated standard source is required to establish the response of the well chamber. An interesting consequence of this analysis is that the Sievert point dose algorithm for clinical sources overestimates the dose on the order of 3% at distances of approximately 3.5 cm from the source.
众所周知，剂量校准器的响应/单位照射率很大程度上取决于源能量。然而，通过经验、分析和蒙特卡罗技术对137铯、192铱和226镭近距离治疗源进行的研究表明，源过滤会显著影响校准器读数与照射率转换因子。结果表明，对于每种临床使用的过滤厚度，都需要一个经照射校准的标准源来确定井型电离室的响应。该分析的一个有趣结果是，临床源的西弗点剂量算法在距离源约3.5厘米处高估剂量约3%。
