"If we can say with 100-percent accuracy that 20 to 30 percent of these [cases] shouldn't go to biopsy, we save some money and save some patients from needless worry," says Yuri Parisky, director of breast-imaging services at the USC/Norris Comprehensive Cancer Center in Los Angeles.
Parisky is leading a multi-institutional study to determine if thermal imaging could help radiologists observe questionable mammogram abnormalities with greater clarity. The painless 10-minute CTI exam is similar to the CTLM approach in theory and patient preparation. A woman lies on the same type of table with a breast suspended through a center ring. But instead of laser light, CTI uses mirrors and a sensitive thermal camera to capture the heat emitted by the breast. Cool air is circulated around the breast, lowering the local body temperature and causing blood vessels to constrict. Malignant tissue has increased blood flow, so it constricts less than normal. That means the tissue stays "hot" and emits a strong thermal signature.
"In mammography, we use radiation that comes out of a machine and goes into a patient. This imaging involves only the heat or energy coming off the patient," explains Robert Hamm, director of breast imaging at Providence Hospital in Washington, D.C.
Highlighting Areas of Concern
The FDA is now considering CTI as an adjunct to mammography; a review panel is expected to meet in October. Lake Oswego, Oregon-based CTI, Inc., emphasizes that the technique is not intended as a substitute for mammography. Because the thermal differences displayed by the CTI system are so minute, the naked eye cannot discern between malignant and benign lesions. Instead, the radiologist uses the patient's mammogram as a guide to identify the area of concern. The CTI system then calculates the likelihood of cancer. "I don't think this is a technology that will be rejected," Parisky says. "Radiologists have long tried to meld anatomic and physiological images. That's just what we've done."
But not everyone boasts the same enthusiasm. The idea of breast thermography dates to the 1970s, and has long been viewed with skepticism. Previous research attempts using heat as a screening tool failed miserably.
"I am quite skeptical about the usefulness based on the dismal experiences with the original thermography studies," says Kathryn Evers, director of mammography at the Fox Chase Cancer Center in Philadelphia.
Parisky says that researchers have overcome that obstacle with equipment that is much more sensitive to heat variation. "I think this opens up a whole new field, now that we have more sophisticated infrared cameras and computers," she adds.
Tonya Powell, 37, volunteered for the CTI procedure after a physical exam revealed a suspicious lump. She wanted to avoid a biopsy or any other invasive breast procedure. "My mother had microcalcifications detected on a mammogram for which she underwent a breast biopsy, which was negative," she recalls.
Powell's thermal scan, when compared with her mammogram, indicated that there was nothing to worry about. Her doctor has advised her to perform routine breast exams. "I have a lot of confidence in the accuracy of the procedure," Powell says.
Milne and Evers suggest that patients ask their physician whether or not a particular test is reasonable. Experts say patients will find the most reliable information concerning the newest technologies at a large university medical center or dedicated cancer hospital.
Kelli A. Miller is a science and medical writer based in Atlanta. She runs NewScience, Inc., and works as executive producer for NewsProNet's Discoveries & Breakthroughs Inside Science TV news service.