Low-Dose Molecular Breast Imaging - Diagnostic and Screening Applications in Women with Dense Breasts

Abstract

Approaches to imaging the breast with nuclear medicine and/or molecular imaging methods have been under investigation since the early 1990s. Nuclear medicine procedures, which detect the preferential uptake of a radiotracer in breast lesions, have the potential to offer valuable functional information that complements conventional anatomical imaging techniques such as mammography and ultrasound.

Despite initial enthusiasm for scintimammography, nuclear medicine techniques in general have struggled to gain mainstream acceptance by the breast imaging community. In the last 5-10 years, older-generation scintillating gamma systems, such breast-specific gamma imaging systems, have been replaced by a new generation of dual detector cadmium zinc telluride [CZT] detectors that perform direct conversion [DC] of gamma ray energy to signal and yield improved spatial and energy resolution. Using CZT-based detectors, DC-Molecular breast Imaging [DC-MBI] has demonstrated the ability to reliably detect breast tumors in a variety of diagnostic and screening settings. Recent improvements in both the detector technology and patient preparation have enabled the associated radiation dose from DC-MBI to be reduced to less than 1.5 mSv. The most robust evidence for the clinical use of DC-MBI is in the screening of women with dense breast tissue. In two large screening studies, the addition of DC-MBI to mammography was significantly more sensitive than mammography alone in detecting cancer (91% vs. 25%, p <0.001). Supplemental screening with DC-MBI detected an additional 8.3 cancers per 1000 women, which compares very favorably to other modalities in screening women with dense breasts.