Evaluation of occupational radiation exposure during pre- and post-treatment procedures in high-dose-rate intracavitary brachytherapy: A comparative study at two Tanzanian cancer centres

Background Occupational radiation exposure during high-dose-rate (HDR) intracavitary brachytherapy is insufficiently characterised, particularly during pre- and post-procedural phases. This study quantified staff exposure and its variability across two cancer centres to guide optimisation of radiation safety practices. Materials and methods A six-month prospective study was conducted at two Tanzanian centres using cobalt-60 HDR afterloading systems, involving 29 healthcare professionals across five roles. Pre- and post-procedural exposure was measured with calibrated survey meters at representative staff positions, integrated with time-and-motion analysis of task duration, workflow, and source-to-staff distance to estimate role-specific doses. Thermoluminescent dosimeters (TLD-100) measured cumulative whole-body dose, contextualising pre- and post-procedural contributions. Dose variability and dose–distance–duration relationships were analysed using regression and correlation models. Results Centre A recorded significantly higher occupational doses and task durations than Centre B (p < 0.005). Substantial role-specific variation was observed, with nurses, anaesthesiologists, and oncologists receiving the highest exposures. Dose correlated inversely with distance (R 2 > 0.82, p < 0.001) and positively with duration (ρ > 0.8, p < 0.001). Pre- and post-treatment activities contributed >40% of cumulative exposure at Centre A, versus <40% at Centre B, except for radiotherapists. All exposures remained below recommended limits (<3.1%). Conclusion Occupational exposure varied by institution and role, influenced by workflow and facility design. Centre A showed three-to fourfold higher task-based doses and ninefold longer exposure durations than Centre B. Targeted optimisation of pre- and post-procedural practices can substantially reduce staff dose and strengthen adherence to the ALARA principle in resource-constrained settings.