Establishment of diagnostic reference levels in cardiac computed tomography.

Mohammad Rawashdeh,Charbel Saade,Mostafa Abdelrahman,Mark F Mcentee,Haytham Alewaidat,Patrick Brennan,Maha Zaitoun

doi:10.1002/acm2.12711

Abstract

The aim of this study was to determine diagnostic reference levels (DRLs) for cardiac computed tomography (CCT) in Jordan. Volume computed tomography dose index (CTDIvol) and dose–length product (DLP) were collected from 228 CCTs performed at seven Jordanian hospitals specialized in cardiac CT. DRLs for cardiac CT were defined at the 75th percentile of CTDIvol and DLP. CTDIvol and DLP were collected from 30 successive cardiac CT in each center except for one center (18 scans). The 75th percentile of the CTDIvol and the DLP of the centers calculated from mixed retrospective and prospective gated modes were 47.74 milligray (mGy) and 1035 mGy/cm, respectively. This study demonstrated wide dose variations among the surveyed hospitals for cardiac CT scans; there was a 5.1‐fold difference between the highest and lowest median DLP with a range of 223.2–1146.7 mGy/cm. Differences were associated with variations in the mAs and kVp. This study confirmed large variability in CTDIvol and DLP for cardiac CT scans; variation was associated with acquisition protocols and highlights the need for dose optimization. DRLs are proposed for CCT; there remains substantial potential for optimization of cardiac CT examinations for adults in Jordan.

Highlights

Radiation doses differ between hospitals for standard‐sized patients undergoing the same examination.[1]
These are representative of Computed tomography (CT) scanners being used across Jordan
Dose in CTDIvol and dose–length product (DLP) was provided in 30 successive cardiac CT scans in each center except for one, which provided 18 scans

Summary

Introduction

Radiation doses differ between hospitals for standard‐sized patients undergoing the same examination.[1] These dose variations are “primarily attributable to local choices regarding technical parameters, rather than patient, institution, or machine characteristics.”. Computed tomography (CT) has a large range of scanning options that lead to a large variation in patient radiation doses. Several factors affect radiation dose to patients undergoing cardiac computed tomography (CCT) procedures.[2] Concerns have been raised about the radiation exposure of CCT. Prospective gated mode (PGM) was developed to reduce radiation dose. PGM, known as “step‐and‐shoot” or “sequential scan mode,”[3] has been developed as an alternative mode to standard helical (spiral) scanning with retrospective electrocardiographic gating with the aim of decreasing radiation dose during CCT to patients with stable heart rates. Once the contribution of factors is established, operators can consider corrective action in a cost‐effective manner.[4]

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