血管内近距离放射治疗剂量影响因素的研究

Study of dose-influencing factors in endovascular brachytherapy

目的 研究32 P球囊预防血管再狭窄的影响因素。方法 采用组织等效血管和热释光剂量学方法。结果 2 5mm× 2 0mm空球囊内残留32 P对血管壁造成的剂量影响是 0 92Gy min。当球囊内导管偏离中心时 ,球囊外表面的吸收剂量将降低 2 0 %。气泡位置处的吸收剂量比球囊外表面平均吸收剂量低约 30 %。结论 32 P球囊表面轴向剂量分布较均匀 ,但径向吸收剂量随距离增加迅速减少。血管内近距离放射治疗有很好的临床应用前景。

Objective To study the 32 P balloon beta dose-influencing factors in preventing endovascular restenosis. Methods The blood vessel wall was substituted by muscle equivalent material.Determination of the dose of the vessel wall was performed by thermoluminescence dosimetric method. Results When 32 P liquid remained in the empty balloon,the dose of the vessel wall was increased by 0.92 Gy/min. When the center catheter was closed to the balloon wall,the absorbed dose of the balloon surface decreased by 20%. When there were air bubbles in the balloon,the dose adjacent to air bubble lowered by 30% than the average absorbed dose of balloon surface. Conclusions The results show that the axisal absorbed dose of 32 P on balloon surface is uniform but the radial dose distribution is attenuated very rapidly with distance. The endovascular brachytherapy has good perspectives,but there are many problems to be solved for its clinical application.