Establishing national diagnostic reference levels (DRLs) for computed tomography in Egypt

Objectives: To establish national diagnostic reference levels (DRLs) in Egypt for computed tomography (CT) examinations of adults and identify the potential for optimization. Methods: Data from 3762 individual patient's undergoing CT scans of head, chest (high resolution), abdomen, abdomen-pelvis, chest-abdomen-pelvis and CT angiography (aorta and both lower limbs) examinations in 50 CT facilities were collected. This represents 20% of facilities in the country and all of the 27 Governorates. Results were compared with DRLs of UK, USA, Canada, Japan, Australia and France. Results: The Egyptian DRLs for CTDIvol in mGy are for head: 30, chest (high resolution): 22, abdomen (liver metastasis): 31, abdomen-pelvis: 31, chest-abdomen-pelvis: 33 and CT angiography (aorta and lower limbs): 37. The corresponding DRLs for DLP in mGy. cm are 1360, 420, 1425, 1325, 1320 and 1320. For head CT, the Egyptian DRL for CTDIvol is 2-3 times lower than the DRLs from other countries. However, the DRL in terms of DLP is in the same range or higher as compared to others. The Egyptian DRL for chest CT (high resolution) is similar to others for DLP but higher for CTDIvol. For abdomen and abdomen-pelvis DRLs for CTDIvol are higher than others. For DLP, the DRLs for abdomen are higher than DRL in UK and lower than those in Japan, while for abdomen-pelvis they are higher than other countries. Conclusion: Despite lower DRLs for CTDIvol, an important consistent problem appears to be higher scan range as DRLs for DLP are higher. (C) 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.