Tatcher M, Kuten A, Helman J, Laufer D
J Oral Maxillofac Surg. 1984 Feb;42(2):108-10. doi: 10.1016/0278-2391(84)90321-5.
The influence on cobalt 60 dose distributions of typical metal parts used in oral and maxillofacial surgery was studied. Relative doses were determined by exposing x-ray films in a polystyrene phantom set-up containing samples of Vitallium, titanium, and stainless steel. Optical densities were converted to doses with the aid of sensitometric curves. The results show that for normal incidence there is a 25% to 40% increase in dose at the entrance side of the metal and a 20% to 25% decrease in dose at the exit side. The enhancement effect falls off rapidly and becomes negligible at about 1 mm from the interface. The reduction effect decreases more gradually and is still evident at distances of a few centimeters. These dose perturbations should be taken into account in the planning of radiation therapy for patients in whom metal objects have been implanted.
研究了口腔颌面外科中使用的典型金属部件对钴60剂量分布的影响。通过在含有维他灵、钛和不锈钢样品的聚苯乙烯体模装置中曝光x光片来确定相对剂量。借助感光曲线将光学密度转换为剂量。结果表明，对于垂直入射，在金属的入射侧剂量增加25%至40%，在出射侧剂量减少20%至25%。增强效应迅速减弱，在距界面约1毫米处可忽略不计。减少效应下降得较为缓慢，在几厘米的距离处仍很明显。对于植入了金属物体的患者，在放射治疗计划中应考虑这些剂量扰动。
