基托材料对125I粒子屏蔽效果的初步研究

Shielding property of different prosthetic materials to shield radiation of 125I seed

目的探讨应用赝复体或修复体承载125I粒子进行肿瘤治疗时，不同修复材料对125I粒子辐射的屏蔽作用。方法125I粒子为放射源，用热释光剂量元件进行测量，建立体外照射模型。载体选用纯钛板、钴铬合金板、聚甲基丙烯酸甲酯板，以铅板为对照，比较各种材料板的屏蔽效果。结果在距离放射源10mm处，经屏蔽后剂量分别为0．09mm纯钛板2．805mGy，0．48mm钛板1．082mGy，0．410、0．671mm钴铬合金板为0．390、0．261mGy，1．685mm聚甲基丙烯酸甲酯板为2．885mGy。结论钴铬合金的屏蔽效果优于其他材料，聚甲基丙烯酸甲酯对125I粒子具有一定屏蔽作用，与0．557mm以上钛板共用可达到铅板防护效果。

Objective To investigation the shielding property to 125I of several different prosthetic materials used in clinical when prostheses are used as carriers of 125I seed in tumor treatment. Methods 125I seeds were taken as the radiation sources to establish a model in vitro and the radiation doses were measured by thermoluminescent dosemeters （TLD）. The shielding property of titanium plate, cochrome plate, and poly methyl methacrylate （PMMA） plate were detected, calculated and compared with that of plumbum plate in the control group. Results The radiation doses of the radiation source at 10 mm distance through the following materials were measured, and the results are 2. 805 mGy （0.09 mm thick titanium plate）, 1. 082 mGy （0. 48 thick titanium plate）, 0. 390 mGy （0. 41 mm thick cochrome plate）, and 0. 261 mGy （0. 67 mm＇s cochrome plate）, and 2. 885 mGy （1. 685 mm thick PMMA plate）. Conclusions The shield property of cochrome is optimal. The poly methyl methacrylate behaves to some extend as a shield to the 125 I seed which can shield the radiation as the effects of plumbum when adopted together with the 0. 557 mm＇s（ or more） titanium plate.