Molecular breast imaging: use of a dual-head dedicated gamma camera to detect small breast tumors.
OBJECTIVE
Molecular breast imaging with a single-head cadmium zinc telluride (CZT) gamma camera has previously been shown to have good sensitivity for the detection of small lesions. To further improve sensitivity, we developed a dual-head molecular breast imaging system using two CZT detectors to simultaneously acquire opposing breast views and reduce lesion-to-detector distance. We determined the incremental gain in sensitivity of molecular breast imaging with dual detectors.


METHODS
Patients with BI-RADS category 4 or 5 lesions < 2 cm that were identified on mammography or sonography and scheduled for biopsy underwent molecular breast imaging as follows: After injection of 740 MBq of technetium-99m ((99m)Tc) sestamibi, 10-minute craniocaudal and mediolateral oblique views of each breast were acquired. Blinded reviews were performed using images from both detectors 1 and 2 and images from detector 1 only (simulating a single-head system). Lesions were scored on a scale of 1-5; 2 or higher was considered positive.


RESULTS
Of the 150 patients in the study, 128 cancers were confirmed in 88 patients. Averaging the results from the three blinded readers, the sensitivity of dual-head molecular breast imaging was 90% (115/128), whereas the sensitivity from review of only single-head molecular breast imaging was 80% (102/128). The sensitivity for the detection of cancers < or = 10 mm in diameter was 82% (50/61) for dual-head molecular breast imaging and 68% (41/61) for single-head molecular breast imaging. On average, 13 additional cancers were seen on dual-head images and the tumor uptake score increased by 1 or more in 60% of the identified tumors.


CONCLUSIONS
Gains in sensitivity with the dual-head system molecular breast imaging are partially due to increased confidence in lesion detection. Molecular breast imaging can reliably detect breast lesions < 2 cm and dual-head molecular breast imaging can significantly increase sensitivity for subcentimeter lesions.
Hruska
Carrie B
CB
Department of Radiology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA. hruska.carrie@mayo.edu
Phillips
Stephen W
SW
Whaley
Dana H
DH
Rhodes
Deborah J
DJ
O'Connor
Michael K
MK
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D015902:Gamma Cameras; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D008875:Middle Aged; D015336:Molecular Probe Techniques / Q000295:instrumentation*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D017256:Technetium Tc 99m Sestamibi
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi