July 29, 2008 -- Women who avoid mammograms for fear that they may be
painful could one day have a comforting alternative: A scan that never touches
John M. Boone, PhD, of the University of California Davis Medical Center
discussed a novel technique called dedicated breast computed tomography (CT) at
the American Association of Physicists in Medicine 50th meeting today in
Traditional mammography squeezes breast tissue between cold, metal plates.
Some women find the exam uncomfortable, even painful, causing them to delay or
even avoid breast cancer screening -- an action that can have dire
avoided mammograms because they are just too uncomfortable? Share your
experiences on WebMD's Women’s Health: Friends Talking board.)
Dedicated breast CT offers a gentler approach: The woman lies face down on a
special table and suspends one breast through a hole. A unique scanner circles
the breast -- no painful compression involved -- snapping virtual
"slices" of breast tissue. The scans take only a few seconds. A
computer reconstructs the information into a highly detailed, 3-D image.
CT scanners have long been used to peer into the brain, lungs, and belly
area. Yet experts had dismissed the notion of breast CT for fear that standard
CT machines would expose women to excessive radiation. The specialized cone
beam breast CT (CBBCT) scanner, developed by Boone and colleagues, uses the
same amount of radiation as a conventional mammogram.
So far, researchers at the university have used the machine to scan 160
The team's initial tests show that the scanner delivers high-resolution
images that clearly demonstrate breast lesions. Boone, a medical physicist,
predicts the method could be available to women within the next 3-4 years.
Dedicated breast CT "is better [than] mammography for mass
detection," Boone says in a news release. [The technique offers]
"improved comfort to the patient and a better three-dimensional
understanding of pathological lesions when they are present."
The method does have its drawbacks. It can miss tiny areas
(microcalcifications) that can sometimes signal early breast cancer.
Mammography is better at spotting such changes.
"We're not making the claim that breast CT is better than mammography --
yet," Boone says.
Early this year, Boone's team started experiments with a combined CT/PET
breast scanner, which allows clinicians to track a tumor's metabolic activity.
Cancer cells have higher metabolic rates than healthy cells and look different
on a PET (positron emission tomography) scan. The combined device would be used
to monitor cancer and plan treatment in patients already diagnosed with the
"PET/CT would not be used for screening because PET is too expensive and
the radiation levels of both procedures would be too high for annual
testing," Boone tells WebMD. "The PET/CT studies would be more useful
for follow-up imaging after mammography, before or after treatment.'"