|On Target (March 1999)|
Gamma camera's future looks bright
by James Schultz
Stan Majewski, head of Jefferson Lab's detector group, heeded his wife's insistence that he work neither Christmas eve nor day. But while friends and family enjoyed an extended holiday break in late December, Majewski found himself back in the laboratory keeping long hours. His mission: to track down a malfunction bedeviling one of the Lab's most successful examples of technology transfer.
While in late-autumn clinical trials at Johns Hopkins University in Baltimore, the device, a breast imager derived from JLab expertise in gamma-ray detection, was unable to produce clear pictures of potential tumors. Alarmed, the imager's licenser, Dilon Technologies, Inc. of Newport News, turned to Majewski for help.
Majewski and his team traced the difficulties to pressure-induced mechanical fluctuations that occurred after the instrument's original calibration in September 1998. The fluctuations affected a key optical coupling, located in the imager's detector head, creating distortions in breast-imaging readouts. Operators could have ameliorated the problem by re-calibrating the instrument prior to examination, but were unfamiliar with the machine's capabilities. The answer: Majewski modified the optical coupling, adding thicker padding to cushion components, and issued more explicit calibration guidelines.
"This technology is on the fast track to implementation," Majewski says. "We've put ourselves under tremendous pressure. For a while there I was wondering: Have we made a system that works? I felt we did. It was a matter of figuring out what was going on and then fixing it. Which is what happened."
Unique and Precise
The "gamma camera" - called the Dilon 2000 by its manufacturer - has its origins in the sensitive gear used in the Lab's experimental halls to detect subatomic particles. Thus it was in 1994 that the Lab's Detector Group adapted JLab detector technology in the creation of a portable, scale-model imager to be used in conjunction with traditional x-ray mammography. The Lab's gamma camera would prove especially sensitive to small breast tumors that otherwise might escape detection.
Breast tissue varies in density. In x-ray mammography, and particularly in the case of younger women, dense tissues create shadow images that can shroud the extent of cancerous tumors too tiny to be easily seen. The gamma camera can track injectable "radiopharmaceuticals" (slightly radioactive isotopes) as they accumulate in a patient's malignant cells and then sense emitted particles. The particles are in turn converted into electrical signals and interpreted as a real-time, computer-aided image of the entire breast.
Having licensed the Lab technology, Dilon Technologies is bullish about the gamma camera. More Dilon 2000 prototypes are under development and should be deployed over the next several months in clinical trials in hospitals around the country. Dilon expects that when production is ramped up, the company could annually produce up to several hundred of the $130,000 breast imagers.
The camera will come in two versions: six-by-eight inch and five-by-five-inch sizes respectively. The technology may also one day be adapted into additional, "application-specific" diagnostic devices for other parts of the body.
"By the end of this year we'll be shipping product," predicts Lee Fairchild, Dilon's director of product marketing. "Initial items will be sold to high visibility sites - people who are doing and who are known for breast imaging."
Fairchild credits Majewski and his team for "a super job," characterizing Dilon's relationship with the Lab as "excellent." For his part, Majewski believes most of the gamma camera's outstanding technical issues have been resolved. Now, he contends, it will be a matter of operator training and repeated use to take full advantage of the camera's promise.
"In comparison with other instruments, the camera appears to perform well," Majewski says. "We believe it will provide significantly better images of small lesions."