NEW YORK (Reuters Health), Aug 12 - Radiation exposure can be reduced using dual-source CT instead of 16- or 64-slice CT for coronary angiography, but only if dose optimization protocols are used, according to a report in the August 15 issue of Heart.
By reducing the number of coronary segments that cannot be assessed because of heart motion at higher heart rates, dual-source CT should significantly reduce dose exposure, the authors explain, but this has not been confirmed.
Dr. J. Rixe from Kerckhoff Heart Center, Bad Nauheim, Germany, and colleagues compared the effective radiation dose estimates using different dual-source CT protocols with those of 16- and 64-slice multidetector CT in 292 patients undergoing CT coronary angiography.
Overall, the mean estimated radiation dose of all patients investigated on a dual-source CT scanner (11.4 mSv) was higher than the dose of patients investigated on a 16-slice multidetector CT (9.8 mSv) or on a 64-slice multidetector CT (8.6 mSv), the authors report.
Reducing the tube voltage of dual-source CT to 100 kV, using a narrow electrocardiogram pulsing window of 110 msec in the diastolic phase, and using a minimum current of 4% of the maximal tube current level reduced the effective radiation dose to 3.8 mSv, which was significantly lower than the calculated radiation doses of all other patient subgroups examined on a dual-source scanner.
All patients examined under a 100-kV dual-source CT protocol received significantly lower estimated radiation doses than did patients scanned on 16- or 64-slice multidetector scanners, regardless of heart rate, the investigators say.
"This study demonstrates that dual-source CT has the potential to reduce radiation dose exposure, if the scan protocol is adjusted appropriately," the researchers conclude.
"Dose optimization thus remains a highly important concern that must be dealt with by cardiologists, radiologists, and manufacturers of multidetector CT scanners," the authors add.
Heart 2009;95:1337-1342.
Last Updated: 2009-08-11 17:55:45 -0400 (Reuters Health)
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