Estimation of effective dose for whole body 18F-FDG PET/CT examination

Abstract

Whole body flourine-18-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is part of the standard management of oncologic diagnosis and staging. However, there is a growing concern over the radiation exposure of patient undergoing PET/CT due to higher radiation dose compared to other imaging modalities. The aim of this study is to estimate the effective dose received by 104 patients that undergone a whole body 18F-FDG PET/CT at the University of Malaya Medical Centre (UMMC). The effective dose from CT were calculated using two methods, namely, dose length product (DLP) method as recommended by International Commission on Radiological Protection (ICRP) Publication 102 and size specific dose estimates (SSDE) method as recommended by American Association of Physicist in Medicine, AAPM Report No. 204. Meanwhile, for PET dosimetry, the effective dose resulting from the radiopharmaceutical injection was estimated by means of the model proposed by ICRP Publication 106. The average effective dose for a whole body 18FFDG PET/CT examination was found to be 14.82 ± 3.2 mSv for DLP method and 9.47 ± 1.5 mSv for SSDE method. DLP method shows over estimated effective dose because average malaysian population is smaller than reference Perspex phantom which is 32 cm diameter. From this study, estimates lifetime attribute risk (LAR) based on BEIR VII report is only 0.09% for SSDE method compare to DLP method which is 0.14%.