High-resolution scans last four to 10 minutes

They deliver high-resolution PET images, yet PEM Flex Synergy and PEM Flex Solo-two extraordinarily compact high-performance PET scanners-take up no more space than the corner of a desk.

Much of the early development of these products has focused on supporting animal research applications. But lately the company that created them has hatched grander plans. And preliminary results indicate that Naviscan PET Systems may be onto something.

Physicians and engineers at the Rockville, MD-based company are grooming the two PEM (positron emission mammography) devices to assess breast tumor margins as a means for surgical planning and postsurgical evaluation. The technology might also be used to evaluate the efficacy of chemotherapy, as well as non- or minimally invasive experimental treatments.

"The sites we are working with are most interested in using this device for problem solving. If, for example, the patient has a suspicious mammogram or physical exam, this would provide more information to help her decide what would be the appropriate next step: a different study or a biopsy," said Naviscan CEO Michael J. Strauss, an experienced physician entrepreneur.

The technology might also be useful in evaluating the efficacy of chemotherapy during clinical trials of new pharmaceutical agents. Strauss, as the founder of Health Technology Associates, a consulting firm that served the pharmaceutical industry before its sale to Corning, has a special knowledge of this area.

"We're getting interest from groups that especially want to look at dense breasts," he said.

PEM Flex Synergy is used in conjunction with a stereotactic x-ray device, specifically a Lorad stereotactic biopsy system. It includes software that automatically overlays registered images of each FDG-based PET slice or a maximum intensity projection of all slices onto 2D x-ray images. PEM Flex Solo, as the name implies, is a freestanding PET scanner. It operates on its own but includes an access port from which data might be obtained, for example, using ultrasound for real-time correlation and intervention.

Naviscan PET Systems, formerly PEM Technologies, has evolved the two platforms based on clinical research studies conducted at leading academic institutions and the National Institutes of Health.

The miniature detectors built into the PEM Flex Synergy and PEM Flex Solo are composed of lutetium-based crystals, which yield high count rates and unusually good spatial resolution. But the detector materials are only part of the story.

"We get very close to the tissue that we want to examine-and that gives us a very high count rate," Strauss said.

The two platforms can achieve 1.5-mm intrinsic resolution with scan times of four to 10 minutes. Each utilizes a kind of slot scanner. The detector is built into a bar that moves across a breast compressed by a paddle, much as is done in conventional x-ray mammography.

"We appear to be picking up very early lesions," said Naviscan president Irving N. Weinberg, a PET physicist and physician luminary who founded the company in 1995, referring to small-scale studies published in the Annals of Surgical Oncology. "Now we need to validate those findings in large clinical trials."

The company is applying funds obtained from the NIH Small Business Innovation Research program, as well as from private investors, to refine and test the technology. Studies are under way at three medical centers.

The two products have already been cleared by the FDA as part of a 510k review process citing commercial PET scanners as substantially equivalent to the new devices. The clinical data will be needed, however, if the company is to market the two products effectively.

"People have to believe that they have clinical value," Strauss said. "They will believe it when they see the data in peer-reviewed literature. We have some published data, and we want to expand that as rapidly as possible."