So fast that you don't even have to hold your breath.
A scan of the entire heart can be performed in only 250 milliseconds, which is less than half a heart beat. In addition, it is possible for physicians to reliably display a heart with a fast pulse or an irregular heart beat without using beta blockers, thus simplifying the workflow and yielding clinical and financial advantages. Owing to its high scanning speed, the Somatom Definition Flash also features new possibilities for performing CT examinations of the heart in the sub-mSv range. This represents a much lower radiation dose than is obtainable with conventional systems, which require doses ranging from 8 mSv to more than 40 mSv. For the first time ever, the heart can thus be examined at a radiation exposure level that is three times lower than the background radiation a person naturally absorbs in a year.