Warm Blanket Lessens Chances Of False-positives In Cancer Scans

In up to 9 percent of patients, doctors have difficulty interpreting scans because of the presence of brown adipose tissue, also known as brown fat, which may lead to a cancer misdiagnosis.

"This is a significant finding," says Medhat Osman, M.D., Ph.D., assistant professor of nuclear medicine and PET director at Saint Louis University School of Medicine. "It is a solution that not only is effective but low-cost and extremely easy for any PET facility to implement."

Osman says brown fat serves an important physiological role – it keeps the body warm in cold temperatures. But accumulations of the tracer that is used to identify malignancies during PET/CT scans that appear in brown fat can mimic cancer – or even mask the appearance of cancer in areas such as the lymph nodes.

New research presented by Osman, co-author Scott Huston and other Saint Louis University Hospital scientists at the 2006 Society of Nuclear Medicine in San Diego this month suggests that covering patients with a heated blanket before the scan can reduce the brown fat uptake by 62 percent.

Researchers currently suggest fighting the problem of brown fat uptake with drugs such as valium and beta blockers, which studies show only reduce the uptake by up to 30 percent.

"A warm blanket is more than twice as effective, and patients don't have to worry about negative drug interactions – or how they’re going to get home after their scan," he says.

While everyone has brown fat, it is more common in women, especially those who are slender, Osman says.

Osman's previous research suggests strenuous activity and consuming caffeinated beverages before undergoing PET/CT scans can also increase the chance for false-positives.

"We always call our patients 24 hours before their appointment as a reminder," Osman says. "Now we can give them a checklist: Don’t drink coffee, take it easy and try to stay warm to ensure the most accurate scan."

In addition to Osman and Huston, Saint Louis University Hospital technologists Crystal Botkin and Penny Yost were authors of the research, which placed third in the technologists section of the meeting.