Digital mammography unit approved

Fischer Imaging has jumped ahead of competitors Bennett X-Rayand Lorad Medical Systems in the digital mammography race (SCAN2/12/92). The three companies are working on charge-coupled device(CCD) x-ray systems for mammographic applications. Fuji MedicalSystems also offers mammography options on its phosphor-platecomputed radiography system.

Fischer received Food and Drug Administration approval forits MammoScan digital imaging system last month for use in guidingthe Fischer Mammotest stereotactic biopsy system (see relatedstory below). The system uses an x-ray intensifying phosphor screenthat is optically coupled to a CCD digital camera.

MammoScan technical highlights include its high image resolution(1024 pixels) and fiber-optics reducer technology, said RobertA. Cascella, executive vice president and CFO for Denver-basedFischer.

A fiber-optics reducer is essentially a series of fiber-optictubes constructed in a funnel fashion that intensifies light.This is used instead of standard lens coupling devices, he said.

"The fiber-optics reducer is mounted to the CCD itself.It reduces the amount of light needed and can offer better resolutionas well as dose reduction capabilities," Cascella told SCAN.

MammoScan currently has a small 50-mm x 50-mm field-of-viewsuitable for breast lesion localization but not full-view mammographyscreening, he said. Fischer is working on a multiple-CCD systemfor standard mammography screening. This technology is two tothree years away from being a commercial product.

There are potential economic as well as diagnostic advantagesto the future use of digital mammography, Cascella said.

"Any time you can propose as good or better resolutionwith dose reduction, there are possibilities in breast screening,"he said. "If you can speed up processing time and throughput,you also provide economic justification to an incremental cost."

Since there is not a large backload of patients currently waitingto use the stereotactic biopsy systems, justification of MammoScanis defined more in terms of patient comfort and convenience, hesaid.

"This (digital localization) dramatically reduces a reasonablyunpleasant process for a patient. If you can knock 15 minutesoff a biopsy procedure, that is a monumental improvement in termsof patient care," he said.

Although testing to determine radiation dose reduction usingthe digital mammography system is still under way, Fischer isconvinced that this safety factor will be another selling pointfor the digital system, he said.

MammoScan also allows for digital processing of the image,including magnification and contrast shading. An Autoguide featureautomatically changes the needle position once lesion coordinatesare digitized and defined, he said.

Fischer expects to have close to 200 Mammotest biopsy systemsin the field by the end of this year, Cascella said. MammoScanretrofits to installed systems involve conversion to the digitalguidance system. The firm is evaluating offering the options offilm, digital, or both on new systems.