WASHINGTONSmall field of view positron imaging, optimized for breast cancer, is jockeying for position among several adjuncts to x-ray mammography. A proponent of the technology, Kathy Schilling, MD, believes it has an edge over MRI.Preliminary work done by Dr. Schilling and her colleagues at the Center for Breast Care in Florida's 400-bed Boca Raton Community Hospital has made her "very optimistic" that positron emission mammography (PEM) will be the definitive tool not only in diagnosis but also in screening and preoperative planning of breast cancer.
Results from a pilot study of women with biopsy-proven breast cancer presented at the Society of Nuclear Medicine annual meeting (abstract 474) indicate that the technology is more helpful than MRI in preoperative planning. The study documented that PEMwith both sensitivity and specificity greater than 90%was as sensitive as MRI in detecting invasive and noninvasive breast cancer, and could identify atypical pathologies better than breast MRI.
"Everything is moving to molecular imaging," said Dr. Schilling, director of breast imaging and intervention at Boca Raton Community Hospital. "I think this will be breast cancer's molecular imaging tool." Boca Raton Community Hospital, which does some 55,000 breast exams annually, routinely applies PEM as part of a research protocol aimed at determining the clinical value of the fledgling tool. PEM images are interpreted by a staff of six radiologists there.With an intrinsic resolution between 1.5 mm and 2 mm, PEM has obvious application as an adjunct in breast cancer diagnosis and possibly screening. The technology characterizes small lesions metabolically, potentially spotting malignancies at an earlier stage than any other technology, according to Dr. Schilling.
Advantages over MRI
Unlike MRI, which requires substantial training to interpret the enhancement patterns created using injected contrast media, expert interpretations using PEM come after experience with 5 to 10 cases, said Dr. Schilling, who teaches breast MRI to physicians interested in applying the modality.
"So many things light up in patients having MRIs, especially patients who are perimenopausal or on hormones," she said, noting that these problems do not affect PEM. "There are a lot fewer false positives on PEM, compared to breast MRI, and yet it is just as sensitive."