Objective: Radioisotopes are used extensively in nuclear medicine. Analysis of occupational doses received by medical radiation workers, especially nuclear medicine staff dealing with radioisotopes, con -tributes significantly to enhancing safe practice and promoting radiation protection measures in the radi-ology department. The current study aimed to determine the time trend and the differences in occupational radiation dose among nuclear medicine workers.Methods: Readings of 394 OSL dosimeters were obtained from 31 medical workers and grouped into five worker groups (technologist, physician, nurse, radio-pharmacist, and radio-physicist).Results: The average number of workers dropped to 4.5 in 2020 and 2021 compared to 14.4 in 2014 to 2019. The average annual effective dose and skin dose for all workers based on measurements for a typ-ical yearly workload of 5000 patients were 1.21 (+/- 1.15) mSv and 2.86 (+/- 1.32) mSv, respectively. The high-est average annual effective and skin dose was 5.41 and 5.82 mSv, respectively. The NM technologist working in PET/CT received higher mean and maximum effective and skin doses than the other worker groups.Conclusion: The annual effective and skin doses were below the national legislation and international standards. However, improvements in radiation protection practices could be implemented to reduce occupational radiation dose to NM technologists, the most exposed worker group in this study.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).