RESUMEN
Objective:To estimate the radiation dose (RD) to the public from patients undergoing 177Lu-prostate specific membrane antigen (PSMA)-617 therapy, and provide reference for the formulation of radiation protection measures. Methods:From July 2020 to January 2021, 10 patients with prostate cancer (age (71.1±5.9) years) who received 177Lu-PSMA-617 therapy in the Affiliated Hospital of Southwest Medical University were retrospectively analyzed. According to the different doses of 177Lu-PSMA-617, the patients were divided into the low-dose (5.55-6.29 GBq) group and high-dose (6.70-8.94 GBq) group. Respectively at 5, 30 min and 1, 2, 4, 24, 48, 72, 96, 144 h after intravenous injection of 177Lu-PSMA-617, whole-body initial dose-equivalent rate (DR) was measured with a radiation-survey meter at 0.3, 1.0 and 2.0 m from the patients. The statistics of ROI were analyzed by HERMES, and the corresponding equations were obtained by fitting the curve regression with double exponential function model. On the basis of human social contact model proposed by the National Council on Radiation Protection and Measurements (NCRP), the RD to the public from the patient discharged from the hospital at different times after completing the 177Lu-PSMA-617 injection was estimated. Results:All patients were discharged from the hospital at 72 h after treatment. The initial DR at 0.3, 1.0 and 2.0 m were (12.6±3.3), (4.7±1.2) and (1.6±0.4) μSv/h, respectively, and the RD to the co-sleeping partner, family members and colleagues who were in contact during the day were (999±253), (121±29) and (160±39) μSv, respectively. If the patients were discharged at 48 h after treatment, the RD to the adult family members could be controlled ≤5 mSv, and the RD to colleagues and children could be controlled ≤1 mSv. Starting from the injection of 177Lu-PSMA-617, the restriction duration for co-sleeping partner and colleagues were both 2 d and the restriction duration for children were 2 d (high-dose group) or 1 d (low-dose group). The patients needed to limit the time for public transportation from the 1st to 4th day after treatment, and there was no restriction from the 5th day. Conclusion:According to the current RD restrictions on the public, 177Lu-PSMA-617 is a relatively safe treatment modality for prostate cancer if good safety precautions are taken.