ACR picks up accreditation of Siemens’ digital mammo unit

The FDA has given the American College of Radiology the authority to accredit the Siemens Mammomat digital mammography scanner as of Oct. 15. It is the last of the four FDA-approved full-field digital scanners to come under the ACR accreditation umbrella.

Siemens' Mammomat digital mammography scanner.

Facilities buying full-field digital mammography units encountered a Catch-22, according to Priscilla Butler, senior director for the ACR breast imaging accreditation program. In order for a facility to be certified, the digital units had to be accredited. But developing an accreditation program can take up to a year after the technology becomes FDA-approved.

"The accreditation programs tended to evolve after a technology became mature. That was not the case with digital mammography," Butler said.

The Mammography Quality Standards Act stipulates that an approved accreditation body must accredit mammography scanners. When the FDA approved the first FFDM unit for marketing in January 2000, it had no mechanism in place for accrediting the digital scanner. The agency developed temporary measures that allowed facilities already certified for screen-film mammography to prove themselves for FFDM by verifying training requirements and performing physics tests.

"This was an interim process that required no phantom or clinical image evaluation, which is a major aspect of the ACR accreditation program," she said.

Accreditation bodies must ensure that facilities are performing quality controls specified under FDA regulations. But the agency has no quality control regulations for scanners, so the manufacturers' regulations become the federal regulations by default, Butler said.

Developing an accreditation program is time-consuming because each manufacturer has different quality control criteria that accrediting bodies must take into account. Before the FDA allows an organization such as the ACR to accredit a technology, it wants to see accreditation materials for exposing the phantom and collecting the clinical images, and those materials must be specific to each manufacturer and technology.

"We have to carefully go through quality control documents and design our program to ensure the facilities are following the criteria defined by the manufacturers," Butler said.

The ACR, FDA, and Siemens have been hammering out the details for accreditation since the FDA approved the Mammomat in August 2004. Facilities that currently own these scanners will be contacted by the ACR regarding the process. They can continue to operate during the transitional period but should not contact the FDA, which had handled the interim accreditation process.

The FDA in 2003 granted the ACR the right to accredit the other three digital mammography machines approved for sale in the U.S.: GE Senographe 2000D (February), Fischer SenoScan (August), and Lorad Selenia (September). The ACR accredits about 95% of mammography equipment in the U.S.; the state handles the accreditation process in Texas, Arkansas, and Iowa.

As of Oct. 1, there were 740 certified mammography facilities with 1040 accredited digital mammography scanners, according to the FDA facilities scorecards statistics.

Siemens has installed about 50 Mammomat units in the U.S., said Joanne Scott-Santos, women's health product manager for Siemens. Butler expects to have all those scanners accredited within six months.

Mammomat distinguishes itself from its competitors in two significant ways, Scott-Santos said. When women with small breasts are imaged, the breasts are kept in the center of the detector, optimizing radiation. And due to the tungsten tube technology, the scanner maintains a high contrast at half the dose.

The ACR appropriateness criteria do not currently distinguish between screen-film and digital mammography. The manual was recently updated to include PET, MRI, and CT in many indications. If the mammography expert panel decides to include digital mammography in any of the indications, especially given the positive results of the Digital Mammographic Imaging Screening Trial (DMIST), it will take that under consideration, said Christine Waldrip, a program specialist in the department of quality and safety program.

For more information from the Diagnostic Imaging archives:

Digital mammography finds more cancers than film in women under 50

MQSA historic success becomes regulatory threat

Report urging changes to breast standards draws fire

Digital mammography creates new opportunities in cancer detection

ACR takes over MQSA accreditation in California