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Departmental Colloquium

Revisiting Decades-Old Physics to Improve Modern Molecular Imaging  
Guest Speaker
Prof. Warren S. Warren  
Guest Affiliation
Duke University  
Prof. Uwe Happek  
Thursday, March 24, 2016 3:30 pm - 4:30 pm  
Physics Auditorium (Rm 202)  
Molecular imaging-the 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. I will focus on two specific modalities-magnetic resonance and optical imaging-and discuss how a close coupling between basic physics on the one hand, and focused clinical questions on the other hand, enable new and important applications. In magnetic resonance, one of the most startling results of the last few decades was our work that showed coherences survive at room temperature between pairs of nuclear spins separated by many microns or millimeters. This gives insight into fundamental questions in quantum mechanics, such as the differences between coherence, correlation and entanglement; it also lets us image temperature in vivo, measure local anisotropy, and detect tissue activation. We have used fundamental symmetries in spin physics to populate states which are immune to most relaxation mechanisms (and thus persist for minutes to hours). Coupled with a new catalytic approach to enhance molecular magnetization by about a factor of 100,000 over thermal values, this can improve the molecular information in clinical imaging. In optics, our lab developed femtosecond pulse shaping technologies two decades ago. Today we know that the "killer application" is to access intrinsic nonlinear signatures at exceedingly low powers (less average power than a laser pointer). This makes it possible to gain image contrast from effects that were not previously observable in soft matter, such as excited state absorption, ground state depletion, and cross phase modulation. Applications to imaging hemoglobins and melanins in tissue to detect and assess cancer will be highlighted; I will also present work on nonlinear imaging of historical pigments in Renaissance paintings to infer the artist’s original colors and intent.