Mammography inspection unsettles imaging vendors

April 22, 1992

Results of a state quality-assurance inspection of mammographyfacilities in Michigan have left some manufacturers indignantand others exultant. But the findings have led to an increasein the number of mammography units in the state that now passnational

Results of a state quality-assurance inspection of mammographyfacilities in Michigan have left some manufacturers indignantand others exultant. But the findings have led to an increasein the number of mammography units in the state that now passnational standards.

In its initial inspection, conducted between December 1990and June 1991, the state reported a failure rate of 17% among330 mammography units. A follow-up inspection, completed in January,found that failure rate had shrunk to 10% of 453 machines, asa result of improved procedures and equipment upgrades.

Publication of inspection results prompted many women to canceltheir mammography appointments or demand new screens at centersthat failed. According to reports published in the Detroit FreePress, the outcry has prompted some hospitals to purchase newmammography equipment. Others are applying for reinspections fromthe state and for national accreditation through the AmericanCollege of Radiology.

The inspection was the first to be conducted under a new lawmandating annual reviews of mammography units. But there are stillkinks to be worked out of the program, according to Vernice DavisAnthony, state health director.

Inspectors used an ACR-accredited phantom to test mammographymachines throughout the state. Those that failed to show testobjects appearing in the phantom flunked the test.

Problems with the inspection method were immediately identified,however, by both hospitals and manufacturers. Some complainedthat units failed only because toner processor volumes were low.

The intent of the inspection is to alert centers to problems,whether they be a lack of toner or outdated equipment, Anthonysaid.

The inspection results were lauded by representatives at GE/CGRand Instrumentarium. Units supplied by both companies scored highon the inspectors' ratings scale. The results show the exam qualitya woman examined with a given unit might have received on thatday, said Edward Barker, general manager of Instrumentarium.

"For someone to say that if they had received advancewarning their equipment would have performed better means theyhave two levels of quality," he said. "The first levelis the one they use when someone is looking and the second isthe level of performance they normally use."

But another manufacturer, Bennett X-ray, charged that the Michigansurvey did not take into account differences between older andnewer units.

"If you're going to survey facilities across the state,obviously some of those facilities are going to be older thanothers, and should be differentiated as such," said WalterSchneider, operations manager. "We went to the state andrequested that it be more consistent."

THE INSPECTION RESULTS ALSO AFFECTED breast imaging centers inother areas of the country. In late February, Prime Time Live,a national news program, named the top four manufacturers whoseequipment was rated best by inspectors. The program prompted mammographyscreening cancellations across the country in centers withouttop-rated equipment, Schneider said.

"We heard from users who told us that they were seeingmany cancellations because Bennett was not on Prime Time Live'slist, even though they have achieved ACR accreditation,"he said.

Where the program succeeded is in demonstrating the importanceof quality assurance, said Instrumentarium's Barker.

"There are a lot of centers that have equipment that shouldpass, but doesn't because they are not paying attention to allthe nits," he said.

Manufacturers that scored a high failure rate in Michigan'sinitial inspection took the opportunity to upgrade and modifyequipment. As a result, failure rates for a second-look inspectionin January decreased for almost all 11 manufacturers, rangingfrom a low of zero to a high of 36%. During the first inspection,failure rates ranged from 3% to 60%.

Equipment is only part of the quality equation for vendorslike GE, Philips, and Instrumentarium, which have in-house qualityassurance programs for their mammography users.

"You also need well-trained technologists and a properlymaintained system that's calibrated at least once per year,"said Brian Johnson, GE's project manager for marketing communications."You need optimum quality control, right down to the properchemicals and experienced radiologists to interpret images."

Barker concurs, adding that darkroom procedures can often makeor break accreditation. The most common reason mammography unitsfail the ACR's accreditation program is faulty processing, hesaid.

"Centers that pass inspection are those that pay the mostattention to quality assurance in the first place," he said."The machine figures in, as does awareness of good mammography,but a lot depends upon the care users take in the darkroom."