- Associated Press - Saturday, July 2, 2016

NEWPORT NEWS, Va. (AP) - Mammograms can be a lifesaver in detecting breast tumors - but the technology falls perilously short for a great many women.

About half of those who undergo mammograms in the U.S. have dense breast tissue that hinders the machine’s ability to find cancers, especially in the early and most treatable stages.

“The mammogram just can’t see through the breast,” said Benjamin Welch, a physicist at Dilon Technologies in Newport News. “So something could be there, and it’s hidden.”

But Dilon is working with Jefferson Lab, also in Newport News, and the University of Florida in Gainesville on a new patent-pending device to fill the void for millions of underserved women.

Called the VASH collimator, the device would attach to a gamma camera and enable dedicated three-dimensional imaging of a breast, giving tumors essentially no place to hide.

In fact, with a patient injected with a low dose of a radiopharmaceutical that binds to cancer cells, any tumor would virtually give itself away.

“Cancer cells are kind of lighting up within the breast,” Welch said. “Think of a firefly at night - it lights up, and that’s how you can find it.”

In non-human phantom tests, researchers say the VASH collimator showed it could enable six times better contrast of breast tumors with equal or better image quality as current methods and at half the radiation dose.

Now, if the device can be honed and made operational, researchers say it could be a game changer.

“What could change the game is to be able to use this technique as a screening tool,” said David Gilland, a biomedical engineer at the University of Florida. “That’s what we want to be able to do with molecular breast imaging, and specifically to target women with dense breasts.”

Step-and-shoot

Dense breasts consist of more connective tissue than fatty tissue. On a mammogram, they appear as a solid white area that makes it difficult to “see” cancers, which also image white, while fat appears dark.

According to Breastcancer.org, research shows that dense breasts are up to six times more likely to develop cancer.

Because of such risk factors, many states now require that women be notified by their clinician if they have dense breasts, said Drew Weisenberger at Jefferson Lab.

Weisenberger is head of the lab’s Radiation Detector and Imaging Group and a partner in developing the VASH device.

The VASH collimator, pronounced CALL-a-mater, works as a kind of filter or lens to the gamma camera - in this case, a Dilon 6800 camera developed by Dilon Technologies years ago using research at Jefferson Lab.

The camera works by imaging gamma rays emitted by a tumor after it accumulates the radiotracer injected into the patient.

The Dilon camera currently provides two-dimensional breast images using a fixed angle collimator with a grid of holes that offers one angle or projection of the breast, Weisenberger explained.

But the VASH system, or variable angle slant hole collimator, consists of a stack of 49 thin tungsten sheets with an identical array of square holes. Two small motors move a set of blocks that slide each sheet slightly, allowing the camera to “see” the breast from various angles.

“Nothing’s moving - the breast isn’t moved, the camera isn’t moved,” Weisenberger said. “The only thing that moves is the collimator.

“In a sense, it’s like a step-and-shoot. Step a little angle, take a picture. Step another little angle, take another picture.”

A biomedical engineer at Jefferson Lab, Seung Joon Lee, came up with the method to accurately manipulate the tungsten sheets.

After all the raw data is gathered, a computer algorithm generates a three-dimensional image of the breast, Weisenberger said, “then that can be used to determine whether there’s a tumor there or not.”

The “or not” is just as critical.

“It’s a more accurate diagnosis,” Gilland said. “Both in terms of the ability to see a tumor at early stages, if it’s there, but equally important to rule out that there’s not a tumor and save the woman, the patient, all the agony of going through a biopsy. That waiting period of finding out.”

‘How it’ll evolve’

In the last several years, mammogram technology has progressed to offer three-dimensional breast images by rotating the detectors and imaging plane around the breast, said Welch.

But mammography, which uses X-rays, is anatomical imaging that essentially makes a shadow of what’s in the breast, he said, while breast-specific gamma imaging is functional imaging using contrast agents to pinpoint cancerous cells.

Current molecular breast imaging systems also use radiotracers, but provide only two-dimensional images, he said. And, while tomographic imaging systems such as SPECT or PET can provide three-dimensional images, those systems are room-size and don’t do as good a job as molecular breast imaging.

The VASH collimator isn’t intended to replace mammograms, researchers said, but to augment them.

Still, if they can get the radiation dose low enough that it’s comparable to or below normal mammograms - yet still provides superior imaging contrast - it could become a viable alternative to mammograms for at-risk women one day.

“We’ll see how it’ll evolve,” said Welch.

Tests will continue during the next several months, then the software will be incorporated into the Dilon camera for even more testing.

Researchers say the collimator also has potential for other cancer detection, such as thyroid or brain tumors.

The device could be operational in two years, they said, although much depends on funding.

The test device was developed on a veritable shoestring budget and in-kind contributions. A state grant of about $30,000 from the Commonwealth Research Commercialization Fund paid for the materials. That fund is managed by the Center for Innovative Technology.

Results of the early phantom tests were presented June 13 at the Society of Nuclear Medicine and Molecular Imaging annual meeting in San Diego.

___

Information from: Daily Press, http://www.dailypress.com/

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