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

Abstract

Objectives: 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.

Methods: 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.

Results: 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).

Conclusions: 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.