Objective  Analyze the individual dose to radiation workers from occupational external exposure in Hangzhou from 2018 to 2022, in order to provide reference for the scientific management of radiation protection for radiation workers.

Method The results of individual dose monitoring of radiation workers in 88 medical institutions in Hangzhou from 2018 to 2022 were collected using stratified random cluster sampling, and the individual doses of radiation workers in different occupational categories, medical institutions, and years of service were analyzed. The Mann Whitney U test is used for comparing data that does not follow a normal distribution between two groups, the Kruskal Wallis H test is used for comparing multiple groups, and the Kruskal Wallis one-way ANOVA (k samples) is used for pairwise comparisons between multiple groups; The comparison of count data between groups is conducted using chi square test.

Result  This study included personal dose monitoring data from 11641 radiation workers. The results showed that the annual collective effective dose was 2.471 person · Sv, and the per capita annual effective dose was 0.12 (0.06, 0.23) mSv/a. Among them, 11450 people had an individual annual effective dose below 1 mSv, accounting for as much as 98.36%. This study showed that there were statistically significant differences in the average annual effective dose of radiation workers among different occupational categories, medical institution types, and work experience groups (H=428.922, P<0.001; H=472.782, P<0.001; H=108.037, P<0.001). In terms of occupational categories, the average annual effective dose for personnel engaged in radiation diagnosis, radiation therapy, nuclear medicine, and interventional radiology is 0.12 (0.06, 0.22), 0.18 (0.10, 0.29), 0.19 (0.10, 0.30), and 0.09 (0.05, 0.20) mSv/a, respectively. Among different types of medical institutions, the per capita annual effective dose of radiation workers in provincial, municipal, county-level, and private medical institutions is 0.16 (0.08, 0.26), 0.10 (0.06, 0.17), 0.11 (0.05, 0.21), and 0.14 (0.07, 0.23) mSv/a, respectively. According to seniority grouping, the average annual effective dose for staff with 10≤seniority<20 years, 20≤seniority<30 years, and≥30 years is 0.11 (0.06, 0.22), 0.15 (0.07, 0.25), 0.14 (0.07, 0.25), and 0.15 (0.06, 0.26), respectively.

Conculsion The annual effective dose per capita of radiation workers in Hangzhou is at a low level, but the individual dose of interventional radiology workers fail to reflect the real level. It is necessary to strengthen the management of standardized wearing, and carry out refined and differentiated management of radiation workers in terms of radiation protection management.