Estimation of Radiation Effective Dose from Abdominal CT Examination Using Two Different Methods

Introduction: Since the introduction of computed tomography (CT), there has been a progressive concern about its associated radiation risk. This study aims to compare the radiation effective dose (ED) of abdominal CT examination calculated by two different methods. Material and Methods Dosimetric data of abdominal CT examination was used to calculate ED for 73 adult patients; 41 males and 32 females. For each participant the ED was calculated three times. The first and second times were by the use of DLP to ED conversion factors ( k -coefficients) which are published by the European Commission (EC) and that specifically published for SOMATOM Definition SA / Siemens CT machine. The other method includes the calculation of ED based on organ dose, which are obtained by CTDI _vol to organ dose conversion factors. Results The ED calculated by both machine specific DLP to ED conversion factor and organ dose method tend to be comparable 7.96 mSv and 8.05 mSv, respectively. A smaller ED was obtained by the use EC’s DLP to ED conversion factor, 7.42 mSv. However, these variations are statistically non-significant. For all calculation methods, ED was higher for female patients than for male patients. Conclusion The abdominal CT ED estimated in this study was within the internationally recommended levels. However, sex-specific ED calculation may be recommended.