Pediatric effective doses and radiogenic risk from computed tomography examinations in Saudi Arabia

In respect of efforts towards optimizing dose, in hospitals worldwide CT dosimetry forms one of the more challenging aspects of this widely used imaging modality, with CT contributing up to 70% of the collective dose to the population from imaging. In Saudi Arabia, while the task is acknowledged to be essential, up to to-date relatively few patient studies have been performed. Current study concerns radiation doses to pediatric patients undergoing CT scans of the head, chest, abdomen, and Cap (chest, abdomen, and pelvis in one scanning procedure), estimates being made of the effective dose. From a study of five hospitals in the Riyadh region, a total of 282 pediatric patients (mean age 5.6±3 and age range from 0.5 to 15 years old) were included in the investigation of dose received, use being made of five multidetector CT machines. The radiation dose parameters were presented in terms of CTDIvol (mGy) and Dlp (mGy.cm). The mean CTDIvol (mGy) was 50.5, 9.4, 10.3, and 11.3 mGy for the head, chest, abdomen, and Cap, respectively. The mean Dlp (mGy.cm) was 912.2, 427.9, 604.3, and 737.9 for head, chest, abdomen, and Cap, in that order. It is evident that the greatest doses were received during head CT procedures, the least being for CT chest examinations. Also evident is that patient doses depended on both the imaging protocol as well as the anatomy of the organ of interest. Patient doses showed wide variations, due to technologist selection of exposure parameters. The patient doses were found to be greater than that recorded for most previous CT studies undertaken locally. Local diagnostic reference level (DRL) was proposed for further dose reduction. (author)