Occupational radiation exposure of zoo veterinarians during x-ray procedures: a real-time dosimetry study

We used real-time dosimetry for the quantitative evaluation of occupational radiation exposure among zoo veterinarians and animal keepers during x-ray procedures to identify key procedural and contextual determinants of exposure variation.

This retrospective observational study analyzed 251 radiographic procedures at multiple zoological facilities in Japan. Occupational exposure was measured in real time with a semiconductor dosimeter that recorded the personal dose equivalent, Hp(10), at 1-second intervals. Procedural variables included professional role, manual restraint, sedation or anesthesia, equipment type, tube voltage (kVp), and tube current-time product (mAs). Between-group comparisons were conducted using nonparametric tests, and multiple linear regression was used to identify the independent predictors of occupational exposure.

The overall median Hp(10) per procedure was 0.35 (IQR: 0.15-0.99) μSv. Veterinarians received significantly higher doses than animal keepers (P = .006). Elevated Hp(10) values were associated with procedures involving large-bodied carnivores, performed without manual restraint or sedation. Multivariate analysis identified 5 significant predictors-professional role (β = -.75), manual restraint (β = -.24), tube voltage (β = .43), tube current-time product (β = .11), and large-animal group (β = .34)-explaining 60.4% of the variance (adjusted R2 = 0.604).

Despite the overall low exposure levels, some procedures resulted in Hp(10) values exceeding 10 μSv. A combination of procedural and contextual factors influenced exposure. These findings underscore the importance of comprehensive radiation-protection strategies, including optimized workflows, appropriate use of sedation, and standardized operator protocols, in alignment with international dose-optimization principles.