OA144] Measuring, monitoring and reporting effective dose on hybrid equipment: Results and challanges to integrate with MDCT in a large population study

Abstract

Purpose The aim of this study was to measure, monitor and report the effective dose in nuclear medicine on s large population and to integrate these measurements with CT dose data. Methods and materials A dose tracking software (GE Dosewatch™) with a NM module was connected to a CT-PET and collected DLP and effective dose from CT modality and administered activity and effective from PET modality. The mean DLP and the mean effective doses with the ranges was assessed for CT. The mean administered activities and mean effective doses for the different radiopharmaceuticals used in PET were evaluated. Examinations were performed with a GE Discovery 690 which has a 64-detector CT scanner; PET scan is performed in stop and go imaging mode. Results Doses data from 11000 CT and 2700 PET were collected, mostly from: Whole Body (WB) 18F-FDG (63.2%), WB 11C-Choline (12.8%), Head 11C-Methionine (18.4%), WB 68Ga-DOTATOC (5.5%). CT mean DLP (mGy*cm) data values were (range between brackets): WB 18F-FDG 1486.3 (76.1-7700.9), WB 11C-Choline 2451.9 (290.9-5023.1), WB 68Ga-DOTATOC 1184.2 (41.0-3728.4) and Head 11C-Methionine 766.7 (52.3-2326.9). Mean effective doses due to CT modality (mSv) were: WB 18F-FDG 15.3 ± 4.7, WB 11C-Choline 26.5 ± 5.6, WB 68Ga-DOTATOC 13.4 ± 2.7 and Head 11C-Methionine 1.7 ± 2.9. Mean administered activity (MBq) and effective doses (mSv) for radiopharmaceuticals used in PET were: WB 18F-FDG 335.9-6.4, Head 11C-Methionine 294.4.6-2.5, WB 68Ga-DOTATOC 168.3-3.5 and WB 11C-Choline 322.2-1.5. The mean total effective doses (mSv) due to both modality were: WB 18F-FDG 21.7 ± 4.9, Head 11C-Methionine 4.3 ± 2.9, WB 11C-Choline 27.9 ± 5.6 and WB 68Ga-DOTATOC 16.9 ± 2.8. Conclusions The implementation of a dose tracking system in nuclear medicine is of great value for accurate and regular recording, reporting and analysis of patient’s effective doses. It can help to improve and optimize the evaluation of radiation exposures in the clinical practice.