A contribution to the establishment of diagnostic reference levels in computed tomography in Brazil

Abstract

Diagnostic reference level is important to guarantee dose optimization, and can be defined nationally, regionally or locally, using dose descriptors, such as CTDIvol and DLP. The aim of this work is to present the local DRL values for a computed tomography (CT) department located in Porto Alegre, Brazil. For this purpose, data have been collected and analyzed, from head, chest and abdomen non-contrasted CT adult and pediatric exams. The DRL values have been compared to those described on previous national studies from UK, US, Germany and Switzerland. The results showed that adult local DRLs using CTDIvol are 50 mGy, 10 mGy and 12 mGy for head, chest and abdomen respectively, and 950 mGy.cm, 350 mGy.cm and 380 mGy.cm for DLP, respectively. These values are similar to the DRLs from Germany, UK, US and Switzerland, for both adult and pediatric exams. The present study is the first of its kind to determine the DRL for CT scanners operating in the south region of Brazil. Similar studies in other regions of Brazil are necessary in order to establish a National Dose Reference Level.