¹⁸F-FDG Whole Body PET/CT 수검자의 거리별 선량 변화에 따른 방사선 작업종사자의 유효선량 고찰

The Consideration of nuclear medicine technologist’s occupational dose from patient who are undergoing ¹⁸F-FDG Whole body PET/CT : Aspect of specific characteristic of patient and contact time with patient

Purpose The purpose of this study is to investigate and analyze the external dose rates of ¹⁸F-FDG Whole Body PET/CT patients by distance, and to identify the main factors that contribute to the reduction of radiation dose by checking the cumulative doses of nuclear medicine technologist(NMT). Materials and Methods After completion of the ¹⁸F-FDG Whole Body PET/CT scan(75.4 ± 3.3 min), the external dose rates of 106 patients were measured at a distance of 0, 10, 30, 50, and 100 cm from the chest. Gender, age, BMI(Body Mass Index), fasting time, diabetes mellitus, radiopharmaceutical injection information, creatine value were collected to analyze individual factors that could affect external dose rates from a patient's perspective. From the perspective of NMT, personal pocket dosimeters were worn on the chest to record accumulated dose of NMT who performed the injection task(T1, T2 and T3) and scan task(T4, T5 and T6). In addition, patient contact time with NMT was measured and analyzed. Results External dose rates from the patient for each distance were calculated as 246.9±37.6, 129.9±16.7, 61.2±9.1, 34.4± 5.9, and 13.1±2.4 μSv/hr respectively. On the patient's aspect, there was a significant difference in the proximity of gender, BMI, Injection dose and creatine value, but the difference decreased as the distance increased. In case of dialysis patient, external dose rates for each distance were exceptionally higher than other patients. On the NMT aspect, the doses received from patients were 0.70, 1.09, 0.55 μSv/person for performing the injection task(T1, T2, and T3), and were 1.25, 0.82, 1.23 μSv/person for performing the scan task(T4, T5, T6). Conclusion we found that maintaining proper distance with patient and reducing contact time with patient had a significant effect on accumulated doses. Considering those points, efforts such as sufficient water intake and encourage of urination, maintaining the proper distance between the NMT and the patient(at least 100 cm), and reducing the contact time should be done for reducing dose rates not only patient but also NMT.