论文部分内容阅读
探讨利用普通钴疗机进行全身照射的剂量学要点。通过将源-体中面距延长至346cm,得到98×92cm~2的近似正方形照射野,其对角线长134cm。为了模拟辐射在人体内的作用,制成一具非均匀人体模型,经CT扫描证实其组织等效性良好。体模剂量测定表明:(1)对于平均大小的病人,其对应的有效照射野为25×25cm~2,并讨论了估价人体有效照射野的方法;(2)体中面剂量始终大于体表剂量,但随着人体厚度增加,体中面/体表剂量比减小,两者之间呈明显负相关(r=-0.983,p<0.001),并拟合了回归曲线;(3)前后野(AP)或AP+左右侧野(RL)照射的剂量分布均匀性优于RL照射;(4)组织补偿可显著改善剂量分布均匀性,并叙述了组织补偿技术。
To discuss the dosimetry points of using general cobalt machine for whole body irradiation. By extending the source-body distance to 346 cm, an approximate square field of 98 × 92 cm -2 was obtained, with a diagonal of 134 cm. In order to simulate the role of radiation in the human body, a non-uniform body model was made and confirmed by CT scanning to be of good tissue equivalence. The phantom dose measurement shows that: (1) for the average size of the patient, the corresponding effective radiation field is 25 × 25cm ~ 2, and discusses the method of evaluating the effective radiation field; (2) the body surface dose is always greater than the body surface (R = -0.983, p <0.001), and fit the regression curve; (3) before and after the dose The homogeneity of dose distribution in field (AP) or AP + left and right field (RL) irradiation is better than that of RL irradiation. (4) Tissue compensation can significantly improve the uniformity of dose distribution and describe tissue compensation technology.