Cardiac CT Radiation Dose Can Be Dramatically Lowered in Some Patients

Radiologists can now lower the radiation dose delivered by cardiac computed tomography (CT) angiography imaging by 39% in adult patients weighing 84 kg or less, according to a new study.

The study, performed at the University of Erlangen (Erlangen, Germany), included 100 patients, weighing 84 kg or less, who underwent cardiac CT angiography either using a tube voltage of 120 kV or 100 kV. The study's findings revealed that the effective radiation dose for patients scanned with 120 kV ranged from 8.8-16.9 mSv; the effective radiation dose for patients scanned with 100 kV ranged from 4.9-11.9 mSv.

"At the same time, the overall image quality was preserved. Image quality scores using 120 kV were 2.7 ±0.5; scores using 100 kV were 2.6 ±0.4," said Tobias Pflederer, M.D., lead author of the study. "Coronary CT angiography has tremendously high accuracy for detecting and ruling out coronary artery stenosis. It is expected that indications for coronary CT angiography will grow in the future. The standard coronary CT angiography protocol uses the higher tube voltage value of 120 kV, however, our study shows that 100 kV can be used instead. It is important to keep the radiation dose as low as possible, especially in younger and female patients."

This study appears in the April 2009 issue of the American Journal of Roentgenology (AJR).

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University of Erlangen