Analysis of dose monitoring results of the ward for permanent seed source implantation treatment in a hospital

Objective: To study the external radiation dose level and distribution in the ward for permanent seed source implantation treatment in a hospital, and evaluate its radiation risk, so as to provide scientific basis for strengthening the radiation protection and supervision of radiation workers in permanent implantation therapy. At the same time, reasonable suggestions for radiation protection are put forward. Methods: The thermoluminescence dosimetry was used to monitor the dose levels of different areas of the ward for permanent seed source implantation treatment for a period of one year, The areas included 10 types of regions in Inpatient Ward. The dose analysis was carried out according to the number of implanted seeds and the days of hospitalization. Results: During the period of one year, a total of 1232 patients were admitted to the ward, of which 432 (190) were treated with permanent implantation of seed source, with a total activity of 2.746843 × 10¹¹ Bq (7423.9 mCi), and an average of 6.3566 × 10⁸ Bq (17.18 mCi) per capita of seed source implanted. The annual hospitalization days of patients treated with permanent seed source implantation were 2478 days, with an average of 6 days. The results of thermoluminescence dose monitoring showed that the dose range of each monitoring point was 0.23 mSv ∼ 13.94 mSv, the average value was 3.37 mSv, and the median value was 1.90 mSv. Among them, the dose range on both sides of the bed and at the infusion rack was significantly higher than that at other points. By dose/activity and dose/(activity · day) analysis, there were statistical differences. Conclusion: There is a point where the external radiation dose is on the high side in the ward for permanent seed source implantation treatment, and the medical staff and accompanying staff should reduce the time of staying at this point or stay away from this point. The annual personal dose monitoring results of medical staff are much lower than the requirements of national standards, and also lower than the results of this experimental site dose monitoring, which is related to the actual work and residence of medical staff. When workers wear protective equipment, within the safe range of dose, the seed implantation activity and average hospital stay can be increased appropriately. Patients wearing protection after operation can significantly reduce their external radiation dose to medical staff. (authors)