FDA Approves ACR Alternative Standard for Testing Mammography Units - 6-27-2005


In a joint effort with the American Association of Physicists in Medicine, the ACR requested an alternative standard to the Food and Drug Administration (FDA) regulations for testing mammography artifacts. On June 16, 2005, the FDA approved the alternative standard, thus eliminating one component of a medical physicist QC test that identifies few if any problems.

In late 2004, the FDA notified the mammography community that their inspectors would begin issuing non-compliance citations to mammography facilities whose medical physicists did not test for artifacts with all available focal spot sizes and target filter combinations used clinically. The ACR and AAPM notified the FDA that they believed strict enforcement of the regulation was unnecessary because testing each target and filter, but not necessarily each combination, adequately identified filter and target problems. For example, testing the molybdenum (Mo) target with the Mo filter and the rhodium (Rh) target with the Rh filter would identify the vast majority of tube related artifacts. Testing the Mo target with the Rh filter was unnecessary work that would not identify additional problems. The ACR Mammography Accreditation Program also intended to submit a request for an alternative standard to this requirement. The FDA announced that they would delay citing for non-compliances on this regulation until they evaluated the ACR alternative standard request.

In order to gather evidence to support this alternative standard, the AAPM solicited data from their members on almost 1000 surveys of mammography units. Over 250 surveys of multiple-target, multiple-filter tubes were submitted. No survey identified an artifact detected with one target used with a single filter that was not detected with a different target used with the same filter, indicating the additional test was unnecessary. On May 12, 2005, the ACR submitted the alternative standard request to the FDA.

On June 16, the FDA approved the request with the following conditions:

  • The alternative is granted when testing for the annual physics survey only.
  • When following the alternative, if any filter-related artifact is discovered during the test then all clinically used target-filter combinations as specified under the current regulation must be tested.
  • When conducting a mammography equipment evaluation, all clinically used target-filter combinations must be tested.

In approving the alternative standard, the FDA stated

"While we believe that the data did not conclusively prove that the following alternative standard will always detect artifacts that might be discovered by following the current regulation, we do believe that the data does establish a very low probability that significant artifacts will be discovered by strict adherence to the regulation. We also agree that the additional time and expense may not be justified for such a small return."

For additional information, go to the FDA Web site at www.fda.gov/cdrh/mammography.