Dr Murphy was a PhD student of David N Schramm at the University of Chicago, where he pursued research into the nuclear physics of dense stellar cores. Subsequently he conducted research in heavy-ion nuclear reaction physics at the Lawrence Radiation Laboratory of the University of California at Berkeley and at the University of Washington. In 1985 Dr Murphy joined the Space Sciences Laboratory of the Lockheed Palo Alto Research Center. There he contributed to the development of the Advanced Nuclear Gamma-Ray Spectrometer for the Air Force Starscan satellite, the Winkler imaging gamma ray spectrometer for the Air Force, and the Polar Ionospheric X-ray Imaging Experiment (PIXIE) for NASA's Polar Satellite as part of the International Solar-Terrestrial Physics Program (ISTP). The Winkler spectrometer was the first functional gamma-ray imaging system based on the concept of Fourier Rotational Modulation Collimation currently employed by NASA's Ramaty High Energy Solar Spectroscopic Imager. The PIXIE experiment acquired the world's first global images of auroral x-ray emissions during its seven years of operation.
In 1992 Dr Murphy joined the initial development team for the CyberKnife, a revolutionary image-guided radiosurgical system, first as Director of System Development at Accuray Incorporated and later as Senior Research Scientist at Stanford University. The CyberKnife pioneered many of the contemporary innovations in high-precision image guidance and motion tracking for external beam radiation therapy.
Dr Murphy's current research programs are in medical image analysis and registration, machine vision, and automatic control systems for motion-adaptive radiation therapy. He is interested in the application of pattern recognition algorithms to image analysis, the modeling of respiration with neural networks, novel methods of reconstructing computed tomography images, and motion tracking in radiation therapy. Dr Murphy has published more than 100 research articles, 21 book chapters, and two books in nuclear physics, astrophysics, and radiation therapy physics, and has been the principal investigator for four NIH research grants. He is a Fellow of the American Association of Physicists in Medicine (AAPM) and is a member of the editorial boards of Medical Physics, the Journal of Physics in Medicine and Biology, and the Journal of Computational Medicine. Dr Murphy chaired the AAPM task group 75 for Imaging Dose Management during Radiation Therapy and has served on five National Institute of Biomedical Imaging and Bio-engineering grant review panels for Image-guided Interventions as well as the Canada Foundation for Innovation's Expert Committee for Image-guided Surgery.
