Results of preliminary clinical trials of the positron emission mammography system PEM-I: a dedicated breast imaging system producing glucose metabolic images using FDG.

UNLABELLED

Early detection of breast cancer is crucial for efficient and effective treatment. We have developed an instrument for positron emission mammography (PEM) called PEM-I that performs high-resolution metabolic imaging of breast cancer. Images of glucose metabolism are obtained after injection of 75 MBq FDG. The PEM detectors are integrated into a conventional mammography system, allowing acquisition of the emission images immediately after the mammogram, without subject repositioning, and accurate coregistration of images from the 2 modalities. In this article, we present the results of the first clinical pilot study with the instrument.

METHODS

Sixteen subjects (age range, 34-76 y) were studied. All subjects were nondiabetic, nonpregnant, and without a history of cancer. They had recently been found to have suggestive mammography findings or a palpable breast mass and underwent lumpectomy or mastectomy within 2 wk of the study. Results from the PEM study were compared with those from mammography and pathology. A PEM test was classified positive (indicating the presence of cancer) if significant focal uptake was seen in the image or if the counting rate in the breast with suggestive findings was significantly higher than in the contralateral breast.

RESULTS

Of the 16 subjects studied, 14 were evaluable. Ten cancerous tumors and 4 benign tumors were confirmed by pathologic examination after complete removal of the tumor. PEM correctly detected the presence of disease in 8 of 10 subjects. Findings were false-negative in 2 instances and false-positive in none, giving the instrument 80% sensitivity, 100% specificity, and 86% accuracy.

CONCLUSION

Our preliminary results suggest that PEM can offer a noninvasive method for the diagnosis of breast cancer. Metabolic images from PEM contain unique information not available from conventional morphologic imaging techniques and aid in expeditiously establishing the diagnosis of cancer. In all subjects, the PEM images were of diagnostic quality, with an imaging time of 2-5 min.