Assistant Professor College of Veterinary Medicine, Chungbuk National University Cheongju, Ch'ungch'ong-bukto, Republic of Korea
Abstract:
Background: There is no reporting on efficiency and safety of thyroid scintigraphy with small-field-of-view (SFOV) gamma camera in veterinary medicine.
Objectives: To evaluate the efficiency and the radiation safety of SFOV gamma camera for feline thyroid scintigraphy.Animals: Ten healthy cats were used for the study.
Methods: Randomized controlled trials. Three staffs participated in this study (operator, staff 1, and staff 2). The operator administered either 2 mCi or 4 mCi of technetium pertechnetate intravenously. At 20, 40, and 60 minutes later injection, thyroid images were obtained with varied acquisition conditions (100,000 counts, 150,000 counts, 200,000 counts, 30 seconds, and 60 seconds). The images were analyzed by calculating thyroid-to-salivary ratio (TSR) and thyroid-to-background ratio (TBR). Surface and ambient radiations were measured hourly from immediately after the injection up to 6 hours. Cumulative occupational radiation doses were measured during the procedure.
Results: The median value of TSR and TBR aligns with the previously reported normal range. There were no significant differences in TSR and TBR between doses and between acquisition conditions. Four mCi group emitted more ambient (p < 0.05) and surface (p < 0.05) radiation than 2 mCi group. Veterinary staff’s cumulative occupational radiations were significantly higher in 4 mCi group (p < 0.05). Conclusions and clinical importance: The SFOV gamma camera demonstrated adequate image quality even with lower doses and shorter acquisition conditions. The radiation exposure from this procedure seems safe. Therefore, the SFOV gamma camera could be a valuable tool for evaluating the thyroid glands in cats.
