New scan for breast designed at Duke

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New scan for breast designed at Duke

It cuts radiation dose, doesn't hurt

P. Fisher, Staff Writer

Duke University scientists have built a new type of

breast scanner they say is better at finding small

tumors than standard breast cancer screening, while

exposing patients to less radiation. And the best

part: The new scanner does all that without having to

smash a woman's breasts as a traditional mammogram

does.

A Duke physicist and a doctoral student have

determined that their device can find lesions in

cadavers and in models designed to approximate breast

tissue that are half the size of the tiniest lumps

mammography can detect. They expect to begin testing

on women within two years.

Mammograms can reliably detect lumps about 1

centimeter (four-tenths of an inch) in diameter,

though they also pick up much smaller calcium deposits

that may indicate disease. The American Cancer Society

recommends that women get mammograms annually starting

at age 40 -- sooner if they have a family history of

breast cancer.

Tornai, a biomedical physicist and associate

professor of radiology, and doctoral student Randolph

McKinley will present research results today in San

Diego at a meeting of the Society of Photo-Optical

Instrumentation Engineers.

Radiation exposure is already minimal in mammograms,

but Tornai and McKinley's device reduces it even

further, to about one-tenth the dose delivered by a

traditional mammography scanner.

A traditional scan

Traditional mammography scanners use low-energy X-rays

to produce a two-dimensional image. The patient's

breast is held between two plates attached to the

scanner and squeezed to make the tissue thin enough so

the low-energy X-rays can effectively penetrate the

breast. Images can be muddled, however, because

pictures of lumps are captured through layer upon

layer of tissue.

The new Duke device is a computerized tomography or CT

scanner powered by more potent gamma radiation. Tornai

said it produces a three-dimensional image that does

not require flattening the breast and produces a

clearer image of suspicious masses.

But to make the technology safe for routine breast

cancer screening, he and McKinley had to devise a way

to reduce the radiation dose delivered by a CT scan,

which is far greater than the dose patients are

exposed to during a mammogram. Their solution: a

special filter that cuts the dose well below what is

received either during a typical CT scan and or during

a mammogram.

The Duke scanner is years away from being ready for

routine use in screening patients and even further

from being a possible replacement for the mammogram,

which is widely recognized as the best means of

detecting breast tumors. But Tornai and McKinley think

their device has the potential to challenge

mammography.

" I think it could very well be rapidly adopted, "

Tornai said. " Women will accept it now that the

[radiation] dose is so low and there is no breast

compression. "

Physicians widely acknowledge that mammograms aren't

good at spotting tumors in women with many glands and

connective tissues in their breasts, a description

that applies to about 40 percent of patients. Also,

women with breast implants typically can't be scanned

with a mammogram. Breast CT scans could improve

screening for both types of patients, Tornai said.

Tornai and McKinley have already established a spinoff

company, Zumatek, and hope to market the new scanner

commercially.

Mammograms hurt

W. Harrell, 69, a breast cancer survivor, was

at Rex Hospital Friday for a routine mammogram. She

estimates she has had at least 20 of the scans.

" It feels like someone is just pinching you until

they're going to make you yell, " said Harrell, a

retired nurse who lives in Raleigh. " It doesn't last

long but for those few moments, it hurts. I don't

think you could stand it if it wasn't brief. "

Harrell is intrigued by the idea of an effective,

comfortable alternative.

" I wouldn't want to be the first one to trust it, " she

said. " But if it comes on the market and it's for

real, I'd love it. "

Dr. Bird, a Raleigh radiologist who

specializes in mammograms, noted that any potential

challenger to the standard method of screening will

have to prove it is as good as or better than

mammography. That won't be easy, he said.

" [Mammography] has been around for such a long time

and it's been so thoroughly tested it truly is the

gold standard, " Bird said. " It's safe, it's effective,

it's almost universally covered by insurance. "

That hasn't stopped scientists who specialize in

medical imaging from dreaming up alternatives.

Researchers are studying breast scanning devices that

use such methods as ultrasound, magnetic resonance

imaging, or MRI, and digital technology. Tornai said

he knows of at least two or three other groups that

are also working with breast CT scanning.

Bird agrees that pain-free screening has value.

" If it's just as good as mammography and it doesn't

hurt, I'm all for it, " he said of the Duke scanner.

" If they come up with a better mousetrap, I think

that's terrific. "

The Duke scanner would have to be used on large

numbers of patients in a long-term clinical trial and

produce excellent results to win approval by the U.S.

Food and Drug Administration and broad use by

physicians.

Health insurers would probably demand a major trial

comparing breast CT scanning with traditional

mammography before they would consider paying for the

test. And a breast CT scan would almost certainly be

more costly than a conventional mammogram, Tornai and

McKinley acknowledge. A scan might cost two or three

times as much, perhaps more. That could give some

patients pause.

" If it's going to be double the cost, I'd say stay

where we are, " said Harrell, the breast cancer

survivor.

Staff writer P. Fisher can be reached at 829-4753

or jfisher@....