Radiation dose estimates in dual-source computed tomography coronary angiography
Abstract
The purpose of this study was to quantify radiation dose parameters of dual-source CT coronary angiography. Eighty patients underwent contrast-enhanced, retrospectively ECG-gated dual-source CT coronary angiography with heart rate-adapted ECG pulsing using two algorithms: In 40 patients, the tube current was reduced to 20% (Amin1) of the normal tube current (Amax) outside the pulsing window; in 40 patients tube current was reduced to 4% (Amin2) of Amax. Mean CTDIvol in the Amin1 group was 45.1±3.6 mGy; the meanCTDIvol in the Amin2 group was 39.1± 3.2 mGy, with CTDIvol in the Amin2 group being significantly reduced when compared to the Amin1 group (P< 0.001). A significant negative correlation was found between CTDIvol and heart rate in group Amin1 (r=?0.82, P< 0.001), whereas no correlation was found between CTDIvol and heart rate in group Amin2 (r=?0.066). Using the conversion coefficient for the chest, dual-source CT coronary angiography resulted in an estimated mean effective dose of 8.8 mSv in the Amin1 group and 7.8 mSv in the Amin2. Radiation exposure of dual-source CT coronary angiography using an ECG-pulsing protocol reducing the tube current to 20% significantly decreases with increasing heart rates, despite using wider pulsing windows at higher heart rates. When using a protocol with reduced tube current of 4%, the radiation dose is significantly lower, irrespective of the heart rate.
Paul Stolzmann, Hans Scheffel,Thomas Schertler,Thomas Frauenfelder,Sebastian Leschka, Lars Husmann, Thomas G. Flohr, Borut Marincek, Philipp A. Kaufmann, Hatem Alkadhi
Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. hatem.alkadhi@usz.ch
Eur Radiol. 2007 Oct 2; [Epub ahead of print]
