Novel frontiers of dedicated molecular imaging in breast cancer diagnosis

Breast cancer (BC) is the most common cancer in women worldwide. In the last years, the contribution of nuclear medicine has grown based on the use of dedicated molecular breast devices for diagnosis and biopsy. Recent technical improvements have been achieved in order to increase the detection of smaller breast lesions using lower doses of radiotracers as well as to facilitate accurate biopsy sampling. Furthermore, new prototypes have been developed combining anatomic and functional imaging. Although the gamma-emitting ^99mTc-sestamibi (^99mTc-MIBI) and the positron-emitting ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) are the most widely used radiotracers, several new tracers have been investigated to target more specific biologic features of BC like proliferation, angiogenesis and tumour receptor status. Dedicated molecular breast devices have been introduced as an adjunct imaging tool to mammography (MG) and ultrasound (US) in the clinical work-up for BC. Additionally, due to the increased interest in molecular tumour subtype analysis and ribonucleic acid (RNA)-based gene expression profiling tests in the routine clinical practice, a possible new clinical application of dedicated breast imaging concerns locally advanced BC, principally in order to visualise intra-tumour metabolic heterogeneity enabling selection of areas with highest tracer uptake (vital tissue) for core needle biopsy. Hence, it will be possible to more adequately tailor the individual treatment, also enabling therapy response monitoring. This review evaluates the current and future perspectives as well as the shortcomings of breast imaging using dedicated nuclear medicine devices.