Lisa Carstens, BS, RVT; Erik Fausak, MSLIS, RVT; Mathieu Spriet, DVM, MS, DACVR, DECVDI

Background

Positron emission tomography (PET), particularly using the radiotracer 18F-fluorodeoxyglucose (18F-FDG), is increasingly used in both human and veterinary medicine. While human PET imaging is widespread and standardized, veterinary PET is largely limited to academic and research settings. Due to differences in imaging protocols, such as the need for animal restraint and anesthesia, veterinary personnel may have different—and potentially higher—occupational radiation exposures. This study aimed to map the existing literature on occupational exposure during 18F-FDG PET imaging across both fields, addressing concerns about safety and regulatory compliance.

Methods

This scoping review followed PRISMA-ScR guidelines. The authors conducted a librarian-assisted systematic search across five databases (CAB Abstracts, MEDLINE, Scopus, BIOSIS, CINAHL). Studies published from 1978 to 2024 were included if they reported direct measurements of occupational radiation exposure from 18F-FDG PET scans. Both human and small animal studies were considered. Data extraction covered scan protocols, staff roles, dosimetry methods, and exposure levels, with unit standardization to microsieverts per patient.

Results

Out of 643 screened studies, 32 met inclusion criteria (27 human, 5 veterinary). Most used electronic personal dosimeters (EPD). Radiation doses per scan were higher on average in veterinary settings (median 8.6 µSv for technologists) than human medicine (median 5.5 µSv). Task-specific exposures showed the injection phase generally caused the highest exposure. Veterinary protocols, particularly those involving awake animal injections, led to greater close-contact handling and higher exposures. Imaging protocols that injected anesthetized patients yielded lower radiation doses for staff.

Limitations

The scoping review was constrained by a limited number of veterinary studies (n=5) and inconsistencies in study design, dosimetry methods, task definitions, and units. Some veterinary data were from simulations rather than live cases. Only 20% of the data extraction was independently verified by a second reviewer, introducing potential for bias. Furthermore, heterogeneity in reporting limited cross-study comparability.

Conclusions

Occupational exposures during 18F-FDG PET scans are within the U.S. NRC's annual safety limit (50,000 µSv/year), even in high-exposure veterinary scenarios. However, the need for animal restraint and anesthesia can increase exposure risk for veterinary staff. Protocol modifications—such as administering radiotracers after anesthesia—along with staff training and ALARA principles, are key to mitigating risk. Future research should focus on direct, task-specific exposure measurements in veterinary settings across diverse protocols and patient sizes.