背向散射因子在放射治疗中的作用

Effect of Backscatter Factor on Absorbed Dose in Radiotherapy

在不同能量、不同组织厚度、不同组织材料时,与标准背向组织厚度1 cm固体水的剂量进行比较,以探讨"背向散射因子"(BS)在放射治疗中对组织吸收剂量的影响。结果表明,背向散射因子确实对实际吸收剂量有影响,而且背向组织厚度越大、射线能量越小,BS值越大,即对组织吸收剂量的影响越大。放疗中必须根据患者的肿瘤后组织厚度包括射线穿过的床板及治疗床的其它部分,以及射线的能量用BS对肿瘤或组织的实际吸收剂量进行修正,以提高疗效,同时也能更好的保护正常组织。

This paper is to study how the absorbed dose was affected by the organ backscatter caused in radiotherapy.With the change of radiation energy,back organ depth,different back organ material type,the backscatter factor（BS） was determined by measuring the absolute dose compared with 1 cm depth of back solid water.The actual absorbed dose was really affected by the back organ depth in radiotherapy.The BS value increased with the increase of radiation energy,back organ depth.The absorbed dose to organ or tumor should be modified with the measured BS based on the depth of back tissue of the tumor,back organ material type,radiation energy,so as to improve the effect of radiotherapy and to be able to protect normal tissue.