(Near-infrared) fluorescence guidance is increasingly gaining interest within surgical and molecular imaging disciplines. This is defined as the field of Image Guided Surgery or rather Interventional Molecular Imaging. The promise of fluorescence to visualize molecular features of disease in real-time, and with microscopic detail, is considered highly desirable. Unfortunately, the technology also has major shortcomings that are predominantly related to signal attenuation and scattering. Integrating fluorescence imaging with three-dimensional nuclear medicine-based pre-interventional imaging (the hybrid surgical guidance concept) helps to overcome these limitations. At the same time the beneficial features of fluorescence imaging allow for refinement of findings obtained with more routinely used nuclear medicine-based modalities. In this set-up, the multimodal tracers used can be detected via two signatures, namely fluorescence- and radioisotopes and dedicated modalities allow detection of both signals.
Based on both clinical (combined > 750 patients) findings and pre-clinical efforts in tracer development, this lecture attempts to illustrate the strengths and shortcomings of fluorescence imaging in relation to those of nuclear medicine. At the same time the hybrid approaches used help to define the areas where the individual read-outs provide most (clinical) value.