Alternative technologies have become increasingly popular in the last few years to help doctors detect cancerous lesions in women with dense breasts. Experts say dense breast tissue alone can be a risk factor for breast cancer, and mammography -- the standard breast imaging modality - can often miss lesions in women with dense breasts.
Although there are more technologies than ever today that are being developed to image the breast, Michael O'Connor, a medical physicist at Mayo Clinic and a presenter at the 59th annual SNM conference in Miami Beach, made the case for molecular breast imaging (MBI) as an effective screening tool to detect cancer in dense breast tissue.
"Over the past seven years, Mayo has been trying to develop this technology as an alternative to mammography in this population of women," he says.
Besting mammo
A 2010 Mayo study screened high-risk women with dense breasts for the first time using MBI. It detected more cancers in this group than mammography did. "Basically, three times as many cancers were picked up," says O'Connor.
The technology Mayo Clinic developed is based on a cadmium zinc telluride detector. Currently, GE Healthcare and Gamma Medica sell and market cameras using this technology for MBI.
"Depending on which vendor you're looking at, the systems have a pixel size between 2.6 and 2.5 millimeters and there is no dead space so it's ideal for compact detectors," says O'Connor.
The Mayo team has also argued the case for a dual-headed cadmium zinc telluride detector, which is said to increase the detection of very small lesions. "That's the reason we stayed with the dual headed technology; we believe we can get that extra 10-15 percent improvement in sensitivity compared to a single headed system," says O'Connor.
MBI vs. BSGI
MBI is often used interchangeably with Breast Specific Gamma Imaging, or BSGI. Both use a radiopharmaceutical agent to initiate the process, but a slightly different technology can be found in the machines. BSGI uses a sodium iodide scintillator technology, as opposed to MBI's cadmium zinc telluride technology.
Currently, Dilon Technologies is the only company to date that has developed a camera specifically for breast imaging that uses iodide scintillator technology.
"Clinical studies show there is no difference between MBI and BSGI," says Pjerin Luli, marketing and product manager for Dilon.
What does separate out Dilon's system is its ability to guide biopsy once a lesion is detected. GE and Gamma Medica don't offer this capability in their technologies although experts agree it's a critical component for any new modality being developed or currently available for breast imaging.
