18 F-fluorodeoxyglucose specimen-positron emission mammography delineates tumour extension in breast-conserving surgery: Preliminary results.

OBJECTIVES: We aimed to determine whether high-resolution specimen-positron emission mammography (PEM) using fluorodeoxyglucose (18 F-FDG) can reveal extension of breast cancer in breast-conserving surgery (BCS), and assess the safety of radiation exposure to medical staff.

METHODS: Sixteen patients underwent positron emission tomography, and then BCS with intraoperative frozen section analysis on the same day. Resected specimens with remaining 18 F-FDG accumulation were scanned by high-resolution PEM. At least 1 day after surgery, tumour extension was evaluated by three independent experienced readers and by binarized images from the specimen-PEM data. Intraoperative exposure of medical staff to 18 F-FDG was measured.

RESULTS: Specimen-PEM evaluations of binarized images and the three investigators detected all (100 %, 12/12) invasive lesions and 94.4 % (17/18) of in situ lesions using both methods. The positive predictive value of the accumulated lesions was 74.4 % (29/39) for the binarized images and 82.9 % (29/35) for the three investigators. Analysis of intraoperative frozen sections detected 100 % (2/2) of the margin-positive cases, also detected by both specimen-PEM evaluation methods with no false-positive margin cases. The mean exposure of the medical staff to 18 F was 18 μSv.

CONCLUSIONS: Specimen-PEM detected invasive and in situ lesions with high accuracy and allowable radiation exposure.

KEY POINTS: • Specimen-PEM detected invasive and in situ lesions with high accuracy. • Specimen-PEM predicted complete resection with the same accuracy as frozen section analysis. • Breast-conserving surgery after fluorodeoxyglucose injection was performed with low medical staff exposure.