New optical technology could improve breast imaging

Glass tubes channel x-rays to target tissue

A prototype optical system promises to improve the capacity of both digital and screen-film mammography to spot breast cancer, while reducing x-ray dose to the patient. Its developer, X-Ray Optical Systems of Albany, NY, hopes to move the system into clinical trials within a year.

“It’s a glass lens that uses polycapillary technology,” said Walter Gibson, chief technology officer for X-Ray Optical. “Thus far we don’t have a commercial product for diagnostic imaging, but we’re working hard on it.”

The x-ray optical system contains millions of minute hollow channels, or capillaries, through which x-rays travel. The tiny channels, each of which measures between 5 and 50 micrometers in diameter, are designed to bend or focus x-rays onto a point of interest, improving contrast and resolution and thus increasing beam efficiency, according to Gibson. Because the lens has the potential to generate higher resolution images than conventional x-ray optics, the human eye may see patterns of breast disease more easily, including the smallest microcalcifications that often are associated with malignant tumors.

“It could be used with film, digital mammography, or digital radiography,” Gibson said. “Our optics can be used with any digital detectors.”

Gibson believes that the lens might eventually replace conventional scatter grids, which guide x-rays to the target and keep them from spreading out to the surrounding areas. The technology being developed at X-Ray Optical might reduce x-ray scatter while also increasing the transmission of primary photons. The end result would be higher contrast and reduced patient dose, at a lower cost and in less time than standard mammography.

Although the company expects better images and improved lesion identification to result, these expectations are based only on studies conducted with phantoms, Gibson said.

The lens design theoretically overcomes an inherent limitation of traditional optics, which does not efficiently guide and control x-rays. When x-rays or neutrons enter a glass capillary, they reflect off the inner surface with little loss of intensity.

The company was founded in 1990 on the core technology from which the medical x-ray lens is evolving: hollow glass tubes that control the path of x-rays and cold/thermal neutrons. X-Ray Optical has parlayed this technology into customized devices used in materials analyzers sold by other companies. It also makes products tailored for government, university, and industrial laboratories.

The x-ray lens intended for medical applications is being developed in cooperation with the University of Wisconsin and the Center for X-Ray Optics at the University of Albany under a two-year, $750,000 grant from the National Institutes of Health. Gibson is not certain when the product will be commercialized. Its first release, however, will probably take the form of an add-on to existing systems.

“That would be the easiest way to get it into use,” Gibson said. “But eventually, we’d hope to place it on new systems.”