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In the diagnosis of coronary artery disease, using volume scans during coronary CT angiography (CCTA) rather than helical scans has the potential to reduce dose by 91 percent, a study found.

Andrew J. Einstein, MD, PhD, of Columbia University Medical Center in New York City, and colleagues compared the radiation dose associated with the use of a 320-slice volume scanner and a 64-slice helical scanner.

Einstein et al compared radiation exposure of six different scan modes during CCTA with a 64-slice scanner and the Toshiba America Medical Systems Aquilion One 320-slice CT scanner (volume scanning). For imaging purposes, researchers positioned metal oxide-semiconductor field-effect transistor (MOSFET) detectors in anthropomorphic phantoms simulating both the male and female bodies.

Results showed that with use of the 320-slice CT volume scanner, effective dose was reduced by 91 percent, from 35.4 mSv,  without the use of ECG-synchronized tube current modulation, to 4.4 mSv with the use of 100 kVp volume scanning during simulated CCTA.

In addition, researchers found that during a simulated CCTA helical scan via a 64-detector row scanner, the male and female heart absorbed a dose of 113.2 mGy and 96.1 mGy, respectively. 

In contrast, the hearts of male and female phantoms that underwent CCTA via the 320-slice scanner at 100 kVp  at the optimized exposure time absorbed 15.8 and 13.5 mGy, respectively.

“CCTA can be performed by using volume scanning to decrease radiation dose to patients with no meaningful change in image noise, with effective doses of 4.4 mSv at 100 kVp and 5.8 mSv at 120 kVp,” the authors said.

Einstein said that careful attention must be paid to using the correct scan mode in order to obtain diagnostic images at a low dose.

Source: Radiology

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