Comparison of radiation dose in abdomen-pelvis and trunk imaging between 64 slice and 16 slice CT

Abstract

Introduction Development of CT techniques led to a rapid increase in the frequency of use of CT procedures, some of the most irradiating multiphase scanning clinical protocols being the abdomen-pelvis and trunk. Purpose The purpose of this study was to compare the radiation dose received by patients during abdomen-pelvis and trunk protocols, made using two CT equipments, one of 64 slices and one of 16 slices. Materials and methods Exposure parameters and patient data were collected for groups of 30 patients for every protocol and every CT equipment. Average values CTDIvol and DLP (dose-length product) were compared for the two units CT. DLP values were calculated also for each patient using ImpactDose software package.The effective doses were estimated for each patient using the model from the RP 154 publication, as well as using the ImpactDose software. Results For the abdomen-pelvis examinations, the average values for DLP and effective dose are substantially higher for 64-slice CT versus 16-slice CT, although the average CTDIvol is lower for 64-slice versus 16-slice. In the case of trunk examinations, the average CTDI is substantially lower for 64-slice CT versus 16-slice CT, the average values for DLP and effective dose having the same trend. For 64-slice CT, comparing the value obtained for abdomen-pelvis with the value for trunk, we notice that DLP is lower for trunk, although the scanned length is higher, the reason being the values for CTDI much lower for trunk. For 16-slice CT, CDTI values are close for the two procedures, such that the DLP value for trunk is higher than for abdomen-pelvis. Conclusion The study shows the importance of optimizing multi-phase scanning protocols, since they can lead to high levels of doses received by patients due the large numbers of examination sequences, although the CT equipments have values for CTDI and DLP per examination sequence below the baseline.