New molecular imaging technique targets hard to detect breast
10 December 2008
Breast-specific gamma imaging (BSGI), an emerging molecular imaging
technology, is effective in the detection of cancers not found on
mammograms or by clinical exam, according to a study presented at the
annual meeting of the Radiological Society of North America (RSNA).
"BSGI can identify the most difficult to detect breast cancer —
invasive lobular carcinoma," said lead author Rachel Brem, MD, professor
of radiology and director of the Breast Imaging and Interventional
Center at The George Washington University Medical Center in Washington,
DC. "It also can help us detect additional lesions of all types of
breast cancer in women whose mammograms show only one suspicious
Breast cancer affects more women than any other non-skin cancer and,
according to the American Cancer Society, accounts for more than 40,000
deaths annually in the US. Most experts agree that the best way to
decrease breast cancer mortality is through early detection using
mammography and clinical breast exam. However, some cancers are
difficult to detect with mammography and clinical exam, particularly in
the earliest stage when treatment is most effective.
While mammography findings are characterized by the difference in
appearance between normal and suspicious breast tissue, BSGI findings
are based on how cancerous cells function.
"It is this physiological approach to breast cancer diagnosis that
allows for improved cancer detection," Dr Brem said.
is an emerging molecular imaging technology using a high-resolution
gamma camera that allows for imaging with very mild compression of the
breast along with an injection of a low-dose nuclear material called a
radiotracer, which is absorbed by the cells (see image on right).
Because cancerous cells have a higher rate of metabolic activity, the
tracer is taken up by these cells at a higher level than in normal
Dr. Brem and colleagues reviewed the records of 159 women with at
least one suspicious or cancerous lesion found by mammography or
physical exam, who had undergone BSGI to determine if additional lesions
BSGI results showed an additional suspicious lesion missed by
mammography and physical exam in 46 (29%) of the women. In 14 (36%) of
the 39 women who underwent biopsy, the newly discovered lesions were
"The data suggest that BSGI allows for the diagnosis of more and
earlier breast cancers," Dr. Brem said.
Dr. Brem pointed out that BSGI is not meant to replace mammography,
but to be used as an adjunct to mammography. "It is an excellent tool
for locating difficult-to-detect cancers and for screening high-risk
women who have normal mammograms and physical examination," she said.
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