Fluorescence Molecular Tomography (FMT) Imaging Techniques

Recent advances in optical technology have taken fluorescent imaging beyond the standard two-dimensional (2D) epifluorescence imaging into the realm of three-dimensional (3D) fluorescence molecular tomographic (FMT®) imaging for improved localization and quantification in deep tissue. This requires the transillumination of animals (i.e. the passing of light through the animals) rather than the standard surface illumination used for epifluorescence assessment. This advance brought by fluorescence tomography is accompanied by the need for extra care in performing proper imaging. Experimental animals must be prepared for transillumination imaging by hair removal, must be properly injected with imaging agents for optimal delivery to imaging sites and minimization of artifacts, and scans must be set up and acquired under optimal conditions and settings. This technical note provides both the in depth details on performing proper imaging as well as data examples to illustrate the ramifications of suboptimal experimental procedures. Performed properly, the pairing of powerful, deep tissue FMT imaging with appropriate near infrared (NIR) imaging agents allows the detection and quantification of important biological processes, such as cellular protease activity, vascular leak, and receptor upregulation, by accurately reconstructing the in vivo distribution of systemically-injected NIR imaging agents. The ability to use fluorescent imaging agents that detect and quantify a variety of biological activities is already expanding the horizons of pre-clinical research and drug development. T e c h n i c a l n o T e Pre-clinical in vivo Imaging Fluorescence Molecular Tomography (FMT) Imaging Techniques Authors Jeffrey D. Peterson, Ph.D.