New Roles for Molecular Imaging in Precision Medicine

Dr. Harrison H. Barrett
University of Arizona
Tuesday, October 11
4:00 - 5:00 pm
SEH Lehman Auditorium, B1220


The term precision medicine is commonplace in current dialogue, and it is frequently offered as a modern synonym for personalized medicine, but it is fair to ask whether either designation is apt in the context of cancer therapy. One marvels at the efficiency and precision of mapping a patient’s genome, but it is less obvious that the subsequent treatment decisions meet the standards of quantitative accuracy implied by the term precision, or that the treatment is personalized to any significant degree beyond selection of the drug for a particular patient. Consider the following critical open questions:

1. Therapeutic efficacy is defined for populations of patients and measured by clinical trials, so what does it even mean to optimize a therapy for a particular patient? How can you verify that you have done so? This is the Fundamental Conundrum of personalized medicine. How can it be resolved?

2. What biological and statistical models can be used to determine the optimum amount of a therapeutic agent to administer to a patient, taking into account the probability of tumor control and the potential occurrence of toxic side effects? Can the tradeoff between beneficial and deleterious effects of a drug be made quantitatively for an individual patient?

3. A major uncertainty in chemotherapy and targeted radionuclide therapy or immunotherapy is the amount of drug delivered to the tumor bed and, for targeted agents, how much of the drug is bound to receptors on tumor cells and how much is internalized into the cells. How can quantitative measures of drug delivery and targeting efficiency be incorporated into estimates of probability of tumor control for an individual patient?

4. There are many physiological mechanisms by which a tumor can acquire drug resistance. How can we discern which ones are operative in a particular patient? How can we evaluate medical and pharmaceutical interventions that would subvert these defensive strategies? Can the concept of induced drug resistance be made precise?

This talk will show how new methods of molecular imaging can be combined with mathematical methods from image science to provide rigorous answers to these questions.



Dr. Barrett received a bachelor's degree in physics from Virginia Polytechnic Institute in 1960, a master's degree in physics from MIT in 1962, and a Ph.D. in applied physics from Harvard in 1969.  He worked for the Raytheon Research Division until 1974, when he came to the University of Arizona.  He is a Regents Professor in the College of Optical Sciences and the Department of Medical Imaging in the College of Medicine, and he has appointments in Applied Mathematics, Biomedical Engineering and the University of Arizona Cancer Center.  He is a fellow of the Optical Society of America, the Institute of Electrical and Electronic Engineers, the American Physical Society and the American Institute of Medical and Biological Engineering. Dr. Barrett has received 27 U. S. patents and written or coauthored over 250 scientific papers; 62 students have received Ph.D. degrees under his direction. In collaboration with Kyle J. Myers, he has written a book entitled Foundations of Image Science, which in 2006 was awarded the First Biennial J. W. Goodman Book Writing Award from OSA and SPIE.  His other awards include a Humboldt Prize, the 2000 IEEE Medical Imaging Scientist Award, an E. T. S. Walton Award from Science Foundation Ireland, and the 2005 C. E. K. Mees Medal from the Optical Society of America. He was the 2011 recipient of the IEEE Medal for Innovations in Healthcare Technology and also the 2011 recipient of the SPIE Gold Medal of the Society.  In 2014 he received an honorary doctorate in Engineering and Architecture from the University of Ghent in Belgium; he received the Paul C. Aebersold Award of the Society of Nuclear Medicine and Molecular Imaging, and he was elected  to the National Academy of Engineering. His research is in image science, with applications in medicine, astronomy and optics.  He is co-director of the Center for Gamma-Ray Imaging, a Biomedical Technology Resource Center funded by NIBIB. Now in its eighteenth year, the Center develops state-of-the art instruments, algorithms and radiotracers for preclinical studies. A particular interest is in developing imaging methods that will open up new possibilities for personalized cancer therapy.