Dilon Technologies sells its first small gamma camera

Dilon Technologies announced the first purchase order for its small digital gamma camera. The camera, which uses technology developed by the Department of Energy, can provide high resolution and positioning flexibility for breast imaging.

The Dilon 6800, so-called because its sodium iodide crystal array detector head is only 6 x 8 inches, acquires metabolic images using technetium-99m-sestamibi when mammographic findings require further evaluation, according to the company.

The camera works like a standard Anger gamma camera in that the x-ray photons strike a sodium iodide crystal, which emits visible light that is captured by photomultiplier tubes and converted into an amplified electrical signal, according to Lee Fairchild, the company's director of product development. The difference is that, instead of one slab of continuous crystal, the Dilon detector packs 3000 crystals in a 6 x 8-inch imaging area.

"The photomultiplier tubes are packed tightly‹almost acting as one 6 x 8-inch photomultiplier tube‹so we can detect which of these crystals in the grid the gamma ray hit," Fairchild said. "This allows us to accurately image up to the edge of the imaging area. Where a standard camera's Œuseful field of view' might be 2 to 3 inches, we can image within 0.4 inch of the edge of the detector. The benefit is that the camera can be placed against the chest wall and image the breast at any angle, where a standard camera only provides a lateral view."

Fairchild said this allows coregistration with standard mammograms. Dilon has done some work on merging the images but doesn't have a developed product yet.

Another company with a small detector is Digirad, whose detector uses photo diodes instead of photomultiplier tubes.

Dilon is marketing its camera as a breast-imaging device. It's portable and about the size and configuration of an ultrasound machine, with a paddle on a flexible arm. It doesn't compress the breast but has a shield to reduce scatter radiation from nearby organs. Dilon received FDA clearance in the spring of 1999 and hoped to begin shipping the 6800 in the spring of 2000, Fairchild said. But that did not happen.

"Funding was held back," he said. "We had to raise funds to go from development to production. We expect to close funding for production in November. We have some potential customers."

Washington Hospital Center in Washington, D.C. will be the first installation to use the device. It will initially be in the nuclear medicine department, but Dilon is hopeful it will find its way into the hospital's breast center.

The company does not have its own sales force yet and is in negotiations with potential distributors. Dilon believes the small-field camera is not in competition with large cameras.

"We won't compete a whole lot," Fairchild said. "The overlap with large cameras is not that great. We don't do

whole-body imaging, but if a hospital is increasing its capacity in women's health or a breast center and wants to add scintimammography, a big camera can't do that."

Scintimammography does not replace mammography but is an adjunct between mammography and biopsy. Ultrasound breast imaging falls into the same category.

Johns Hopkins University researchers found the camera had a sensitivity and specificity of 94% and 91%, respectively, compared with 82% and 46% for mammography.

"This will help enormously to allow better evaluation of different mammograms or different clinical situations," said Dr. Rachel Brem, director of breast imaging and intervention at the George Washington University Medical Center. Brem was part of the Johns Hopkins Medical Center team that did clinical evaluation of the Dilon 6800. She said her George Washington Center will be buying one.

"It will help us look for multiple tumor localities and will eventually assist in imaging dense breasts in obese women," Brem said.

Fairchild said there is industry work beyond what Dilon is doing to increase acceptance of scintomammography. DuPont, maker of Miraluma (the radiopharmaceutical Dilon uses), which is the only FDA-authorized radiopharmaceutical for breast imaging, is working to increase third-party-payer reimbursement, according to Fairchild.

The imaging procedure is reimbursable under existing CPT code 78800, "radiopharmaceutical localization of tumor, limited area," for between $380 and $600, according to Fairchild, who said the Dilon 6800 is priced at $130,000. Reimbursement depends upon results.

"The CPT code is for tumor localization, which refers to localization of the presence of a tumor," Brem said. "It is the CPT code used by nuclear medicine for imaging malignancies."

Dilon Technologies of Newport News, VA, was formed four years ago by president and chairman Dick Ash and CEO Lon Slane, hence the name "Dilon."