Study to establish diagnostic reference levels of adults CT chest examinations in Algeria

Abstract

The significant patient dose from computed tomography (CT) examinations and the continuously increasing frequency oblige the rigorous application of “diagnostic reference levels” (DRLs) as an optimization tool. The aim of this study is to establish local diagnostic reference levels (DRLs) of CT “Chest Examination”. The survey was carried out in five sites with nine CT scanners. The dosimetric quantities recorded were the Dose Length Product (DLP), in mGy.cm, and the Volumetric CT Dose Index (CTDIvol), in mGy. The value of the NRD was determined from the 75th centile of the mean distribution of the data collected for chest examinations of 180 patients. Median values for each site were also calculated, and the 75th percentile of DLP and CTDIvol was used as a basis to establish local DRLs. The rounded third-quartile of CTDIvol and DLP were 15.21 mGy and 520.2 mGy.cm, respectively. There is a significant variation in term of doses between CT departments also with identical scanners. Such observations indicate the need for improvement through implementation of measures to keep all doses within acceptable ranges for the clinical routine examinations. This is a first survey of CT doses in Algeria which will be used later in the determination of the national DRLs.