University of Waterloo
200 University Avenue West
Waterloo, Ontario, Canada N2L 3G1
Phone: (519) 888-4567 ext 32215
Fax: (519) 746-8115
Molecular imaging - use of chemical signatures to image function instead of merely structure - promises to enable a new generation of clinical modalities that can revolutionize both diagnosis and treatment. Many approaches use targeted contrast agents, but that raises serious issues about human safety and barriers to clinical approval. Instead, our work focuses on development of methods which maximize intrinsic contrast, generally using enhanced control over the probing radiation fields. In optical imaging, our lab has developed advanced femtosecond pulse shaping and detection technologies to access intrinsic nonlinear signatures that were not previously observable in tissue. For example, shaped femtosecond pulses and femtosecond pulse trains can measure nonlinear absorption even in the absence of fluorescence; can quantify self-phase or cross-phase modulation; or can use differences in excited state and ground state dynamics to achieve molecular specificity with microscopic resolution, even in highly scattering media. In all these cases enhanced control over the optical field permits microscopic resolution imaging, much deeper than is possible with conventional microscopy, and enables detection of novel and clinically relevant contrast.
Applications to imaging hemoglobins and melanins in tissue by nonlinear absorption will be highlighted, including recent work published in Science Translational Medicine which could revolutionize melanoma diagnosis by improving the pathology “gold standard.” I will also show extensions of this approach to imaging through opaque pigments in centuries-old artwork, which lets us quantify impurities, identify pigment origin, and see through discolored binder to determine the original artist’s intent.
The University of Waterloo acknowledges that much of our work takes place on the traditional territory of the Neutral, Anishinaabeg and Haudenosaunee peoples. Our main campus is situated on the Haldimand Tract, the land granted to the Six Nations that includes six miles on each side of the Grand River. Our active work toward reconciliation takes place across our campuses through research, learning, teaching, and community building, and is centralized within our Indigenous Initiatives Office.