CT colonography dose varies little over years

The effective doses associated with virtual colonoscopy have remained constant despite the increased use of multislice scanners, primarily due to the use of lower dose protocols, according to a study presented at the 2004 RSNA meeting.

Dr. Sebastiaan Jensch and colleagues from the Academic Medical Center in Amsterdam searched the literature for CT colonography accuracy studies and asked the institutions involved in those studies to provide their current scan protocols.

Both past and current protocols had a median effective dose of 4.2 mSv. The literature search revealed a median mAs of 88, while the current mAs value was 70. In past years, two-thirds of the scans were performed on a single-slice scanner. Today, nearly 90% are performed on multislice scanners.