Harrison H. Barrett, PhD

Regents Professor of Radiology

Regents Professor of Optical Sciences

E-Mail Address: 
Phone Number: 
(520) 626-6815
Short Bio: 

Dr. Harrison H. Barrett is a Regents' Professor in the Department of Radiology within the College of Medicine (COM) and in the College of Optical Sciences.

He earned his PhD in Applied Physics in 1969 from Harvard University while employed by Raytheon Research Division in Waltham, Mass., as a Senior Research Scientist. He stayed with Raytheon as a Project Leader in the Medical Electronics department until 1974, when he accepted a joint appointment of Associate Professor in the Department of Radiology and College of Optical Sciences at the University of Arizona.

Dr. Barrett was appointed Professor in both colleges in 1976 and Regents' Professor in 1990. He also currently holds an appointment of Professor within the Program of Applied Mathematics, the Program in Biomedical Engineering, and the University of Arizona Cancer Center.

Dr. Barrett is Director of the Center for Gamma Ray Imaging (CGRI), founded with a large Research Resource Grant from the National Institute for Biomedical Imaging and Bioengineering (NIBIB) and continuously funded since 1999.

This Center engages in technology development in five projects relevant to the use of radiotracers in medicine, including:

• Gamma Ray detectors.

• Electronics and imaging systems.

• Image science and image quality.

• Adaptive and multi-modality imaging.

• Methods for molecular imaging.

Dr. Barrett also has a MERIT (Method to Extend Research in Time) grant from NIBIB. Funded since 1992, the objective of this grant is to develop specialized parallel computers and apply them to medical imaging.

Current work concentrates on the latest generation of graphics processing units (GPUs). His group has demonstrated huge increases in processing speed in various problems of image reconstruction and optimal parameter estimation.

In his capacity as the Director of CGRI, Dr. Barrett collaborates with roughly 40 groups around the world, often supplying them with advanced detectors, imaging systems, or algorithms tailored to their specific research needs.

Throughout his career, Dr. Barrett has directly supervised 54 PhD dissertations, 20 masters theses, and approximately 10 postdoctoral fellows.

Research Information
Research Program: 
2. Cancer Imaging
Member Status: 
Research Member
Summary of Research Activity: 

Dr. Barrett’s specialty is the emerging field of Image Science, which strives to provide unified theories, design principles and evaluation methods for all forms of imaging.  In recent projects he has applied the methodologies of image science to problems in astronomy and optical metrology, but his main focus has always been medical imaging, especially in nuclear medicine.  He has had over forty years of continuous NIH funding, mainly through the National Cancer Institute (NCI) and the National Institute for Biomedical Imaging and Bioengineering NIBIB).  He is the founding director of the Center for Gamma-Ray Imaging (CGRI), now in its 16th year.  CGRI uniquely combines rigorous theory, state-of-the-art computational tools, advanced detectors and electronics, innovative imaging systems, novel radiotracers and cutting-edge clinical and preclinical applications.  All of this is done within the context of gamma-ray imaging, but it is important to other forms of medical imaging and image science in general.  Dr. Barrett also holds a large NIH R01 grant entitled SPECT Imaging and Parallel Computing, now in year 23, which provides the massive computing resources needed to reach the goals of CGRI.

As leader of CGRI Project II, Dr. Barrett conducts research in several cancer-related areas.  He and his team are developing new methods for estimation of tumor volume, tracer uptake and other parameters.   In another project they are developing methods to assess the therapeutic efficacy of imaging systems when the images are to be used in the planning and monitoring of external-beam radiation therapy or radionuclide therapy.  They are also investigating new techniques and imaging instruments for analyzing drug delivery in chemotherapy;  included in this effort are methods to estimate extravasation rates, diffusion coefficients, binding potentials and other mechanistic (non-compartmental) pharmacokinetic parameters.  Finally, his group is developing new instruments for 2D and 3D imaging of alpha and beta particles emitted by the radionuclides used in targeted radiotherapy.

A major component of CGRI is an extensive collaborative research program, which promotes preclinical and clinical translation of the technologies developed in all of the projects.  There are ongoing collaborations with six major cancer centers: Memorial Sloan Kettering Cancer Center, Fred Hutchinson Cancer Research Center, University of Chicago Cancer Center. Moffitt Cancer Center, Translational Genomics Institute and National University of Ireland Galway.  New collaborations with UACC researchers are also being developed.

Professional Information
Professional Affiliations: 

American Institute of Medical and Biological Imaging, Fellow
American Physical Society, Fellow
OSA, Fellow
Institute of Electrical and Electronic Engineers, Senior Fellow

SPIE, Gold Medal of the Society, 2011
IEEE Medal for Innovations in Healthcare Technology, 2011
SPIE/Optical Society of America Joseph W. Goodman Book Writing Award (with Kyle Myers), 2006
Optical Society of America, C.E.K. Mees Medal, 2005
IEEE Medical Imaging Scientist Award, 2000
Alexander von Humboldt Foundation, Humboldt Prize, 1980
Industrial Research Magazine, IR-100 Award, 1973
Society of Nuclear Medicine Scientific Exhibit Awards, First Prize 1991, Silver Medal 1972, Bronze Medals 1973, 1975, 1983, 1984, 1985, Honorable Mention 1983
Academic Information
PhD, Harvard University, 1969
Master's Degree: 
MS, MIT, 1962
Undergraduate School: 
BS, Virginia Polytechnic Institute, 1960