Hubble X-rays aid health Technology: Space Telescope contributes to making breast exams easier.

February 11, 1997|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

Astronomers won't be the first to benefit from the new instruments being flown up to the Hubble Space Telescope this week.

Thousands of women have already had breast exams and relatively painless needle biopsies made possible by advances in X-ray imaging developed for the Hubble-bound Space Telescope Imaging Spectrograph.

"You've taken a long, drawn-out, anxiety-ridden and expensive event, and made it shorter, easier to schedule and more comfortable," said Dr. David Dershaw of the Memorial Sloan-Kettering Cancer Center in New York.

Spacewalking astronauts are scheduled to install the new spectrograph on the fourth day of the mission, scheduled for blastoff just before 4 a.m. today aboard the shuttle Discovery.

This particular technology spinoff began six years ago at the Goddard Space Flight Center in Greenbelt, where NASA scientists were looking for ways to boost the performance of the spectrograph they were building for Hubble.

Astronomers wanted the new instrument to have greater sensitivity, finer resolution and better contrast than anything now on board Hubble. The solution, they decided, lay in building better "charge coupled devices" (CCDs).

CCDs are the heart of modern telescopic instruments. They are light-sensitive chips that function like the retina of the human eye -- translating incoming light energy into electric signals. The signals are then converted into television images or spectrographic data from the target stars or galaxies.

"Hubble did not invent CCDs, but we drive the technology," said Carolyn A. Krebs, senior instrument development manager for Hubble at Goddard. NASA's money enables the industry to advance CCD technology, and that reduces the cost of manufacturing the devices for other applications.

NASA's CCD contractor was Techtronics Inc. of Beaverton, Ore., which later became Scientific Imaging Technologies (SITe).

SITe knew how to make better CCDs, said Brian Corrie, the company's product applications manager. The challenge was learning to build more than one or two at a time with high reliability. "It was during the STIS [Hubble] contract that that capability was developed," he said.

SITe now makes the new, improved CCDs and sells them to Lorad, of Danbury, Conn. Lorad, in turn, puts them in an X-ray breast imaging device called "StereoGuide."

StereoGuide takes high-resolution X-ray images of a breast from two different angles and converts the CCD signals into a three-dimensional TV image.

The operator can then move a screen cursor onto any suspicious spot, or "lesion," and click a button. A computer then calculates the precise location of the targeted spot within the breast.

The machine guides a biopsy needle precisely to the lesion, where it extracts a small tissue sample.

More than 500,000 American women undergo breast biopsies each year, usually under a surgeon's knife. However, 70 percent to 85 percent of the lesions turn out to be harmless and don't require further surgery.

With the clear images and precise guidance of the new CCD technology, Krebs said, even the biopsy surgery can be avoided. Several studies have found these "stereotactic, large-core needle biopsies" to be just as accurate as surgical biopsies, and much cheaper -- $850 as compared with $3,500 for surgical biopsy in one published comparison.

The savings, according to some estimates, will approach $1 billion a year, including reductions in health care costs and lost wages.

"It's gratifying," Krebs said. "It's easy for the public to understand how the space program has contributed Tang or Teflon. But this is a good example of the more subtle things that are going on. I don't think the public realizes how much NASA drives these things."

Other Hubble research may one day lead to even more reliable breast imaging.

Dr. Robert J. Hanisch, head of Data Systems at the Space Telescope Science Institute in Baltimore, said that before the 1993 repair mission, Hubble's flawed main mirror forced scientists to develop computer image processing and enhancement techniques to erase the blur from Hubble's digital pictures.

They also worked to find ways to identify and erase the tiny light spots left on Hubble's images by cosmic rays that struck the telescope's CCDs. Astronomers need to eliminate these spots to get accurate measurements of the starlight they're studying.

"It turns out that detecting these faint cosmic rays is very similar to a problem in mammography -- micro-calcifications," Hanisch said.

Micro-calcifications are tiny clumps of calcium that can be an early precursor to the formation of a tumor.

"On regular mammograms, they are, or can be, very hard to spot," he said. "In a region of complex tissues, you might not even see them at all."

Collaborations with experts at the Johns Hopkins Medical Institutions, the National Science Foundation (NSF) and Kodak two years ago led to the realization that the same techniques used to detect and erase cosmic ray hits can be reversed to identify and enhance these micro-calcifications in the digital imagery.

Thanks to a $50,000 NSF grant, Hanisch said, "we've demonstrated that our approach looks very promising. But we do not have the resources now to pursue it to its logical conclusion."

The Defense Department recently declined a request to finance further research.

"I think it's worth pursuing," Hanisch said. "Perhaps it's not the problem that will lead to the eradication of breast cancer, but there are other areas of astronomy and physics that can be applied to medicine that should be explored further."

Pub Date: 2/11/97

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