125I放射性粒子植入术后患者周围辐射剂量的监测

背景与目的:影像引导下125I放射性粒子植入治疗是微创治疗的一种新技术,作为恶性肿瘤综合治疗方法之一,它具有创伤小、定位准、疗效确切等特点,因此应用越来越广泛,而125I放射性粒子对患者及周围人群的辐射损害及其防护也越来越受到重视.本研究旨在探讨125I放射性粒子植入术后患者周围辐射剂量的监测.方法:随机抽取2004年10月至2005年12月在中山大学肿瘤防治中心在CT引导下行125I放射性粒子植入治疗恶性肿瘤患者20例,用γ射线监测仪在术后即时及2、4、6个月后对125I放射性粒子辐射剂量进行监测,将监测结果与室内天然本底剂量进行比较.结果:随着与放射源距离的增大,辐射剂量迅速减少,在距离患者体表50 cm时,测得的剂量已接近室内天然本底辐射剂量;辐射剂量随着时间的推移而递减,在6个月后体表测得的剂量已基本接近室内天然本底剂量.结论:在125I放射性粒子植入术前后对辐射的防护应积极采取隔离防护措施,并注意距离防护、时间防护.只要严格采取了必要的防护措施,125I放射性粒子植入治疗对于患者及周围人群是安全的.

Environmental radiation dose monitor after 125I radioactive seed implantation

BACKGROUND & OBJECTIVE: Medical imaging-guided 125I radioactive seed implantation is a new method of mini-invasive therapy. As a component of combined therapy for malignant tumors, 125I implantation has benefits of minimal invasion, accurate position fixing, and certain clinical effects, and has been widely applied to treat tumors at present. Also the environmental phototoxis and radiation protection have been highly regarded. This study was to investigate the environmental radiation dose monitor after 125I radioactive seed implantation. METHODS: From Oct. 2004 to Dec. 2005, 20 patients with malignant tumors were randomly selected in this study after 125I radioactive seed implantation. Environmental radiation dose was detected right after operation and 2, 4 and 6 months later with gamma-ray equipment. RESULTS: With the increase of the distance from radioactive source, the radiation dose decreased quickly. The detected dose was close to a natural background radiation dose at a distance of 50 cm from radioactive source. With time passing, the environmental radiation dose was attenuated and the detected dose was close to natural background after 6 months. CONCLUSIONS: Addition to the isolation and shielding protection before and after 125I radioactive seed implantation, distance protection and time protection should be considered. With necessary strict protection, 125I implantation is safe to patients and environment.