In a new study presented at the American Association of Physicists in Medicine (AAPM) 52nd Annual Meeting, researchers at the University of Washington reported that 18FDG dose for Positron Emission Mammography (PEM) could be reduced by as much as 70% without affecting
image quality. PEM scanners are high-resolution breast PET systems that show the site as well as the metabolic phase of a lesion. The metabolic view enables doctors to take the optimal decision for patient care by providing an unequalled ability to discriminate between benign and malignant lesions, what is called "specificity". PEM differs from x-ray mammography in that it is currently not used as a screening test for cancer presence, rather is deployed to confirm spread of disease in a patient already diagnosed with a primary breast cancer. Wendie Berg, MD, Breast Imaging Radiologist, Lutherville, MD, said "We have several tools to help us make better patient care choices. Mammography is our primary screening tool. PEM is used in women with known breast cancer in order to plan treatment," he added "Radiation for treatment of breast cancer uses doses which are roughly 5000 times higher than a diagnostic PEM study. Minimizing radiation dose is still important for any patient, and we can likely cut the dose of PEM in half, but the benefit to proper treatment exceeds the still low risk from the radiation dose of PEM."
More about PEM and low radiation doses.
Dr. Lawrence MacDonald, Research Assistant Professor in the Department of Radiology at the University of Washington, and his team presented results of a study to detect cancer with very low doses of radiation using the Naviscan PEM scanner. Primary results using phantom images suggest that PEM lesion detection can be reduced down to approximately 3 mCi injected dose of 18FDG or 3 to 4 times lower than the dose usually used in clinical practice, but at the same time the lesion remains detectable. These results are the basis of a subsequent clinical trial at Swedish Cancer Institute which aimed to determine the optimal dose levels of FDG needed to produce high quality PEM images in patients with breast cancer. Judy Kalinyak, MD, Medical Director, Naviscan, Inc., said "Naviscan believes that the radiation dose to patients who undergo PEM can be cut at least in half, if not more as suggested by the University of Washington study," he added "Our site in Japan is already injecting 5 mCi of FDG compared to the 10 mCi in the US and a recently published abstract in The Journal of Nuclear Medicine further validates the reduction in dose down to 5 mCi."
Results from a recent presentation at the Society of Nuclear Medicine on findings from an NIH-sponsored clinical study comparing between PEM and breast MRI further confirm PEM's clinical effectiveness. This multi-site study (NIH Grant 5R44CA103102) of hundreds of women with newly diagnosed breast cancer shows that PEM offers a six %increase in specificity at comparably high sensitivity, and also recommended fewer unnecessary biopsies. These results are particularly important for women who cannot tolerate an MRI exam and require an alternate imaging technique. The study is going to be published in the December issue of the journal Radiology. Naviscan, founded in 1995, develops and markets compact, high-resolution PET scanners intended to develop organ specific molecular imaging and guide radiological and surgical procedures. The Naviscan PEM scanner is currently implemented and available in breast and imaging centers throughout the U.S. and other countries. The Company is headquartered in San Diego, California and is the first to obtain FDA-clearance for a high-resolution PET scanner designed to image small body parts and for breast biopsy image guidance.