Radiation dose in 320-detector-row CT coronary angiography: Prospective ECG triggering combined with multi-segment reconstruction

Background: The aim of this study was to investigate patient doses in prospective electrocardiogram (ECG)-triggered CT coronary angiography (CTCA) combined with multi-segment reconstruction on a 320-detector-row CT. Methods: CTCA data acquired with prospective ECG (pECG) triggering at 0-100% (pECG(100%)). 30-80% (pECG(50%)), 70-80% (pECG(10%)) of the R R interval and reconstructed using mono-, two- and three-segment reconstruction were investigated. Effective doses were estimated by using LiF-TLDs placed at several organ sites in an Alderson-Rando phantom. Results: With pECG(100%). the estimation of effective dose of data reconstructed using mono-segment (pECG(100%_1S)) reconstruction was 10.01 +/- 0.56 mSv. For data acquired using pECG(50%), the effective doses were 6.16 +/- 0.12, 9.92 +/- 0.37 and 13.51 +/- 0.17 mSv in mono-segment (pECG(50%_1S)). two-segment (pECG(50%_2S)) and three-segment (pECG(50%_3S)) reconstruction, respectively. The effective dose of data acquired with pECG(10%) and reconstructed using mono-segment (pECG(10%_1S)) reconstruction was 3.61 +/- 0.07 mSv. We observed a difference of around 7.46% between effective doses estimated using TLD-phantom measurement and CT dose index (CTDI) obtained from the scanner. Conclusion: For patients with low and intermediate heart rate, radiation exposure could be reduced by 38.6% or more by narrowing pulsing window width. Although slightly higher radiation dose was observed in multi-segment reconstruction, this method can be used in high heart rate patients to provide data of high temporal resolution without increasing radiation exposure when it is combined with prospective ECG triggering. (C) 2011 Elsevier Ltd. All rights reserved.