Article

Proposed national diagnostic reference levels for computed tomography examinations based on clinical indication, patient gender and size and the use of contrast in Lebanon

¹ Saint-Joseph University, Faculty of Sciences, Laboratory of “Mathematics and Applications”, Beirut, Lebanon
² National Council for Scientific Research, Lebanese Atomic Energy Commission, Beirut, Lebanon

^* Corresponding author: c.rizik@cnrs.edu.lb

Received: 31 October 2022
Accepted: 27 March 2023

Abstract

This study aims to propose national diagnostic reference levels (DRLs) for computed tomography (CT) scans performed on adult patients based on clinical indication (CI), patient gender and size and the use of contrast in Lebanon. The volume CT dose index (CTDI_vol), size-specific dose estimate (SSDE) and dose length product (DLP) were collected between July 2017 and May 2022 from 14 Lebanese hospitals. The data were collected from at least 20 patients for 15 common group of CIs (GCIs) in the head, thorax, abdomen (AB), abdomen-pelvis (ABP) and thorax-abdomen-pelvis (TABP) regions. National DRLs were calculated for each GCIs, patient gender and size and depending on the use of contrast as the third quartile of the CT units’ median values of CTDI_vol, SSDE and DLP. The proposed national DRLs in term of CTDI_vol (DLP) were 65, 15, 9, 9 and 13 mGy (1104, 483, 520, 442 and 611 mGy.cm), respectively, for Head/Hemorrhage, ABP/Appendicitis, AB/Abdominal pain, Thorax/Covid-19 and TABP/Trauma. The proposed national DRLs were higher than those from the literature pointing up the need for a dose optimization strategy to protect the patient from the harmful effects of radiation.