The American College of Radiology said Wednesday a registry that helps radiologists see where they stack up against their peers has logged about 5.5 million CT scans.

The Dose Index Registry, which launched in May 2011, collects anonymized dose information from CT scans. Providers can then check how their dose indices compare to regional and national benchmarks.

The technology works with a "light piece of software" installed in the clinic or department, which automatically receives the dose information from the CT scanner or from the PACS, ACR told DOTmed News.

By participating in the registry, doctors can meet some of the requirements for Medicare's Physician Quality Reporting System next year, which provides incentives for physicians who share quality measures with approved registries, ACR said. The rules for the PQRS 2014 measures will be finalized later this year.

So far, ACR said about 600 sites are registered, and of those 328 are sending scan information to the registry. The college estimates there are some 8,000 CT sites in the country.

Currently, the registry only supports CT scans, but ACR said later this year they'll also expand to cover digital radiography (CR and DR). Eventually, they'll also move on to fluoroscopy and other modalities.

Annual fees for participating range from $500, for only a handful of radiologists or sites, to $10,000, for more than 55 radiologists at scores of sites, according to the ACR website. There's also a one-time $500 registration fee.