New Gamma Camera Technique Detects Small Tumours

A diagnostic device that resembles a mammography unit can detect breast tumours as tiny as one-fifth of an inch in diameter, which may make it a valuable complementary imaging technique to mammography, say researchers at Mayo Clinic.

The new technique uses a new dual-head gamma camera system and is sensitive enough to detect tumours less than ten millimeters in diameter in 88 percent of cases where it is used. Early findings from an ongoing comparison of the device with mammography show that it can detect small cancers that were not found with mammography, say the investigators. “Our ultimate goal is to detect small cancers that may be inconspicuous or invisible on a mammogram for high-risk women with dense breasts,” says physicist Michael O’Connor, Ph.D.

The investigators also say their device will likely be only slightly more expensive to use than mammography, and will be much more comfortable for women because much less pressure is needed to image a breast. The investigators used new, small semiconductor-based gamma cameras and incorporated them into a new breast imaging system. Images obtained with these gamma cameras are not affected by dense or fatty tissue. In the procedure, women are injected with a small amount of the radioactive drug sestamibi that preferentially travels to tumours, which absorb the substance.

The research team used this system to scan 100 patients who had suspicious breast lesions that were small, with a diameter of two centimeters or less. Eighty-two cancers were later identified at surgery in 54 patients. The gamma camera detected 76 of the cancers, giving it a 93 percent success rate in these cases. Some were missed, either because the breast was not properly positioned in the device or because they were too small to detect with this technology (two to four millimeters), says O’Connor. Still, the gamma camera was 88 percent accurate in picking up cancers less than 10 millimeters.

( Source: MEDICA.de )