Bhatnagar J P, Spira J
Acta Radiol Ther Phys Biol. 1975 Aug;14(4):337-46. doi: 10.3109/02841867509132674.
The central axis percentage depth dose of a 43 MV roentgen ray beam from a betatron, is found to decrease with increasing beam area at depths more than the depth of maximum dose build-up. At depths less than the depth of maximum dose build-up, a reverse trend is seen. This type of variation of central axis percentage depth dose with beam area is found due to the presence of extraneous radiation originating in the field flattening filter (compensator) and the collimator of the betatron.
发现来自电子感应加速器的43兆伏伦琴射线束的中心轴百分深度剂量，在超过最大剂量建成深度的深度处，会随着射野面积的增加而降低。在小于最大剂量建成深度的深度处，则观察到相反的趋势。中心轴百分深度剂量随射野面积的这种变化类型，是由于电子感应加速器的射野均整滤过器（补偿器）和准直器中产生的杂散辐射所致。
