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.”