术中照射限光筒剂量学研究

Dosimetric Research on Applicator Dosimetry for Intraoperative Radiation

术中照射是一项有价值的放疗技术。术中照射限光筒可以自行设计和制作。作者对术中照射限光筒制作和应用中的剂量学问题进行讨论和研究。限光筒的材料、尺寸和形状均可对剂量学结果产生影响，对每台加速器都应具体研究，术中照射限光筒制作后应仔细进行剂量测试。不同的Ｘ线光阑设置会有不同的剂量输出特性，要选择最佳的ｘ线光阑开度以达到满意的剂量输出特性。即增加８０％剂量深度，产生较小的韧致辐射效应并得到较高的输出剂量。在应用多野照射时相邻野之间的间隔要防止肿瘤部位出现剂量热点或冷点。斜入射的角度不易过大。

Intraoperative radiation is a valuble radiotherapy. The applicator for intraoperative treatment can be designed and made by yourself. The manufacture of the radiation applicator and the dosimetryin the application are discussed. The materials, size and shape of the applicator will effect on dosimetry results. The dosage should be measured very carefully before application, and suitable set of x-ray collimator should be chosen to obtain more satisfactory output characterization, so that depth of dose level can be increased by 80%, flatness of the field can be improved, surface dose can be reduced as much as possible, bremsstrahlung will become less and higher output factor of the beam. The distance between two neighboring fields should prevent hot and cool points of dose to appear. The angle of oblique incidence should not be too large during treatment.