Volumetric Temporal Focusing Microscopy for Fluorescence-Guided Surgery - PROJECT SUMMARY In this project, we will develop a volumetric temporal-focusing microscope for back-table pathological assessment in fluorescence-guided surgery. Despite technological advances in medical imaging, surgery is typically guided by manual palpation and nonspecific visual cues to differentiate diseased tissue. To confirm the result, surgical procedures must stop and wait for the results of frozen section histopathology. Fluorescence-guided surgery promises real-time speed and subcellular resolution, and its molecular specificity can identify particular structures through fluorophores targeted to specific cell types. While current implementations of fluorescence-guided surgery can provide real-time wide-field images, it lacks the ability to differentiate between signal from the surface of the tissue versus deeper layers, known as optical sectioning, which is essential for margin detection. We propose using temporal focusing, a wide-field two-photon fluorescence imaging technique which maintains strong optical sectioning. The advantage of temporal focusing is that it can axially scan the focal plane remotely without any moving parts. The aims of this proposal are to develop a volumetric, temporal-focusing microscope for fluorescence-guided surgery and to determine the two-photon excitation spectra of the long-wavelength dyes used in FGS. The long-term goal of this research program is to develop a high-speed, wide-field, depth-resolved optical microscope with no moving parts for imaging deep through tissue. When combined with a pulsed fiber laser, this simple design can be added on to any fluorescence microscope for wide adoption Ultimately, when coupled with fiber delivery, this technique will lead to a probe capable of an ‘optical biopsy,’ or a non-invasive diagnosis through scattering tissue with high-speed 3D imaging. The goals of this instrument-development project align with the institute’s objective of “to improve health by leading the development and accelerating the application of biomedical technologies,” and more specifically, “enhancing existing imaging and bioengineering modalities.”
