肿瘤放射性粒子植入术后病区工作人员辐射防护的再认识

通过对不同距离与屏蔽条件下肿瘤放射性粒子植入后患者的放射性检测,实现辐射防护个体化与最优化。随机选择35例北京大学深圳医院微创介入病区并接受125I放射性粒子植入的患者,植入术后2h内使用x-γ射线检测仪在不同距离处检测未屏蔽、0.25mmPb屏蔽、0.5mmPb屏蔽条件下患者的剂量当量率,采用统计软件包SPSS19.0对结果进行t检验分析,并按照病区工作人员平均每人每日接触患者2h计算相应的年剂量当量。未屏蔽时,0.5m处工作人员所受的年剂量当量小于放射工作人员限值20mSv,2m处接近公众限值1mSv,4m处相当于病室内本底;在0.25mmPb屏蔽下,尽管零距离处35位患者的平均年剂量当量小于公众限值,但其中有6位患者的年剂量当量大于公众限值;在0.5mmPb屏蔽下,零距离处所有患者的年剂量当量已接近本底。结果表明,125I粒子植入后病区工作人员的工作时间、距离、屏蔽防护中,重点要做好个体化的屏蔽防护。0.25mmPb的铅胶布是最常使用的屏蔽物,对于粒子植入数量较多或植入部位表浅的患者必要时也应使用0.5mmPb的铅胶布屏蔽,以实现辐射防护个体化和最优化。

Recognition of Radiological Protection of Ward Staff after Brachytherapy for Malignant Tumor with Radioiodine Seeds

Through radiation measurement of the patients after brachytherapy with radioiodine seeds for malignant tumor at different distances and shielding condition, the importance, optimization and individualization of the radiological protection are well recognized. The 35 patients were randomly selected in the minimally invasive interventional ward of Peking University Shenzhen Hospital who underwent brachytherapy for malignant tumor with radioiodine seeds. Within 2 hours after the brachytherapy, the radiation of the patients without shielding, with 0.25 mmPb and 0.5 mmPb shielding were detected by an x-γ ray detector at different distances (equivalent dose rate). The results were analysed by SPSS19.0 t test. Annual equivalent dose was calculated by the average close contact time (two hours everyone per day). The average annual equivalent dose of the 35 patients without shielding was below 20 mSv at 0.5 meter, close to the public limit 1 mSv at 2 meters and equivalent to the background at 4 meters. Under 0.25 mmPb shielding, 6 patients’ radiation was still above the pubic limit, although the average radiation of the 35 patients was below the pubic limit; under 0.5 mmPb shielding, all patients’ radiation was nearly equivalent to the background at 0 meter. The results showed that among the time, distance and shielded protection, the individual radiological protection was especially important. The 0.25 mmPb lead cushion was the most commonly used shield. The 0.5 mmPb lead cushion also should be used in case of the large number of radioiodine seeds implantation and/or more superficial implant site, so as to ensure the individualization and optimization in radiological protection.