Comparison of sedation and general anesthesia protocols for 18F-FDG-PET/CT studies in dogs and cats: Musculoskeletal uptake and radiation dose to workers.

Abstract

In veterinary medicine, PET/CT scans are generally performed with the patient under general anesthesia. The aim of this prospective crossover study was to compare the musculoskeletal uptake of 18F-FDG and radiation doses to workers during PET/CT studies of healthy dogs and cats between sedation and general anesthesia. Volume and maximal standard uptake values (SUVmax) values of abnormal 18F-FDG uptake in the skeletal musculature, presence of misregistration artifact, and radiation doses to workers for each PET/CT study were recorded. Sedation was associated with increased volume of 18F-FDG uptake in the musculature of the thoracic limbs (p=.01), cervical (p=.02), and thoracic (p=.03) spine. Increased volume and SUVmax of the musculature assessed altogether were associated with the lighter degree of sedation (p=.04 for both). A significant decrease in the odds of misregistration artifact was observed for anesthetized animals in comparison with sedated (OR: 0.0, 95% CI: 0.0-0.0, p=.01). Radiation doses to workers were significantly higher for sedation compared with general anesthesia (p=.01) and for the anesthesia technician compared with the nuclear medicine technologist (p=.01). Use of sedation for PET/CT studies in dogs and cats is feasible. However, it is associated with increased physiologic musculoskeletal uptake of 18F-FDG in the thoracic limbs, cervical, and thoracic spine, with increased frequency of misregistration artifact, and with increased radiation doses to workers. These limitations can be overcome by recognition of the uptake pattern and monitoring/rotation of the involved staff at institutions where a high caseload is expected.