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.