HARRISON H. BARRETT
2000 Medical Imaging Scientist Award
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At last year’s IEEE Medical Imaging Conference in Lyon, France, Harrison H. Barrett, Ph.D., was presented with the prestigious IEEE Medical Imaging Scientist Award in recognition of his outstanding contributions to the field. Presented in alternate years, this award honors an individual for significant innovations, research contributions, and influence on medical imaging science through education.
Dr. Barrett, who is Regents Professor of Radiology, Optical Sciences, and Applied Mathematics at the University of Arizona, was cited for substantial research accomplishments in the physics, mathematics, and engineering aspects of medical imaging science. In addition, he was recognized for a history of outstanding mentorship and leadership contributions. He was nominated by an impressive roster of 32 collaborators, including many former students who have become highly prominent scientists in their own right.
Dr. Barrett has been a creative innovator of the theory and technology of imaging science for over 30 years. His research results are significant, extensive, and fundamental (he has over 250 publications and over 20 patents); the impact of his research has been immediate and lasting.
Dr. Barrett received the Ph.D. in Applied Physics from Harvard University in 1969. In 1971, he accepted a position as a Project Leader in the Medical Electronics Unit of the Research Division of Raytheon Corporation. This move initiated his research efforts in medical imaging science which have continued for 30 years (and counting). In 1974, he moved to the University of Arizona as an Associate Professor in the Optical Sciences Center and the Department of Radiology, and two years later was promoted to full Professor. In 1990, Dr. Barrett was honored by the University of Arizona with the title of Regents Professor.
In 1972, Dr. Barrett published “Fresnel zone plate imaging in nuclear medicine”, which reported some of the first results of the use of coded apertures in nuclear medicine and included the first use of the term “coded” to describe an aperture that multiplexes images. From 1971 to 1985, Dr. Barrett authored or co-authored over 50 publications on the foundations of tomographic imaging. Some were analysis of coded aperture systems; others of more conventional systems.
From 1982 to 1995, the development of high-resolution, high-sensitivity nuclear medicine systems for dynamic 2D and 3D multiple-pinhole coded- and non-coded aperture imaging served as a framework for many of Dr. Barrett’s investigations. In 1984, Dr. Barrett proposed the development of modular scintillation cameras as a means of increasing system sensitivity through the increasing of system count rate. The development of modular cameras involved the development and implementation of schemes for maximum-likelihood position estimation and was followed by the development of several multiple-pinhole coded-aperture modular-camera systems, including a system known as FASTSPECT.
The degree of mathematics and physics rigor found in Dr. Barrett’s research sets his results apart from those of most other investigators in medical imaging science. This is particularly true of his work to develop methods for objective assessment of image quality. His results include development of analytic model observers and significant use of psychophysical studies with human observers. Analysis of models of lumpy backgrounds contributed significantly to the designs of a variety of counting and imaging probes he and his collaborators built, including dual-detector, esophageal, and collimatorless coincidence probes.
Forward problems, inverse problems, and tomographic reconstruction are pervasive in medical imaging. Dr. Barrett has investigated extensively the noise properties of maximum-likelihood expectation-maximization reconstruction, has developed novel approaches to list-mode likelihood reconstruction, and extensively characterized discrete-data cone- beam tomography.
Dr. Barrett and collaborators are significant contributors to the development of semiconductor arrays for high-resolution gamma-ray imaging, the analysis and use of the pixel information and signal-processing properties of semiconductor sensors, and the use of such sensors in ultra-high resolution planar and tomographic small-animal imagers. This work is the practical implementation of theoretical analysis that demonstrates that a key to optimal system design is maximization of space-bandwidth product.
Professor Barrett has, for over 30 years, been a dedicated, successful educator and mentor. He has been the primary advisor of more than 15 M.S. and 45 Ph.D. students; the impact of that effort alone is extensive. His oral and written expositions are superb; volumes one and two of Radiological Imaging: Theory of Image Formation, Detection, and Processing, which he co-authored with William Swindell, are evidence of this. His writing has been appreciated by hundreds, probably thousands, of medical imaging science students and researchers throughout the world.
Dr. Barrett is a Fellow of the American Physical Society, the Optical Society of America, and the American Institute of Medical and Biological Engineering.
Professor Harrison H. Barrett can be reached at the University of Arizona, Arizona health Sciences Center, Department of Radiology, Tucson, AZ 85724-5067; Phone +1 520 626-6815; E-mail: barrett@radiology.arizona.edu.
KWO RAY CHU
2001 Plasma Science and Applications Award
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Kwo Ray Chu |
The 2001 Plasma Science and Application Award will be presented to Professor Kwo Ray Chu of the National Tsing Hua University, Taiwan on June 20 at the 28th IEEE International Conference on Plasma Science, to be held in Las Vegas in conjunction with the 13th IEEE Pulsed Power Conference. The citation reads “For seminal plasma physics investigations yielding fundamental insight into coherent radiation processes, thereby significantly advancing the state of gyro-oscillator and amplifier technology.”
Kwo Ray Chu received the B.S. degree in physics from the National Taiwan University in 1965, the M.S. degree in physics from the University of Massachusetts in 1968, and the Ph.D. degree in applied physics from Cornell University in 1972. He specializes in plasma physics and, in particular, the generation of coherent electromagnetic radiation via the electron cyclotron maser interaction. After serving as Research Scientist in Science Applications International Corporation (SAIC) from 1973 to 1977, he joined the High Power Electromagnetic Radiation Branch of the U. S. Naval Research Laboratory. There, he headed the Advanced Concepts Section, conducting research on coherent electromagnetic radiation generation. Concurrently, he served for three years as Adjunct Associate Professor in the Department of Applied Sciences at Yale University. Since September 1983, he has been Professor of Physics at the National Tsing Hua University, Taiwan.
In the latter portion of
the 1970’s, Kwo Ray Chu began his theoretical investigations of the electron
cyclotron maser (ECM). His studies of the ECM as a plasma instability (with J. L.
Hirshfield) provided a physical understanding of the competitive relationship between the
relativistic electron cyclotron maser and the nonrelativistic 
force-driven instabilities, thereby clarifying
the physical mechanisms involved in early fast-wave experiments. His detailed
analyses (with A. T. Drobot, V. L. Granatstein, and J. L. Seftor) of the gyrotron
traveling-wave amplifier (gyro-TWT) led to the design for the first demonstration of this
device at the Naval Research Laboratory in 1979. Further studies of the gyro-TWT (with Y.
Y. Lau) identified the absolute instability as an important source of spurious
oscillations and quantified the effect of wall losses. His investigation of the gyrotron
oscillator elucidated the physics of harmonic interactions. This, together with his
kinetic formalism of the gyrotron oscillator (with D. Dialetis), laid the early
theoretical groundwork for fusion-oriented gyrotron research.
In 1983, Kwo Ray Chu joined the Physics Department of National Tsing Hua University in Taiwan, where he continued his theoretical research. His studies of the linear and nonlinear behavior of gyroklystron amplifiers with scientists at the University of Maryland in 1985 resulted in the first multi-megawatt gyroklystron design. This provided strong impetus for U. S. Department of Energy sponsorship of a program to develop the gyroklystron as an RF driver for the Next Linear Collider. His studies of the gyro-TWT (with A. T. Lin) clarified the transition from the convective instability to the absolute instability. His papers on the electrostatic cyclotron instability (with K. R. Chen) pointed out the impact of electrostatic noise amplification in gyrotrons, a subject of current interest to radar-oriented gyrotron amplifier research. His analysis of harmonic multiplying gyro-amplifiers (with H. Guo) revealed the distinctive physical features pertaining to this class of devices. His theory (with A. T. Lin) on the orbital motion of electrons in combined helical wiggler and axial guide magnetic fields exhibited the effect of harmonic gyroresonance due to axial magnetic field reversal and provided an explanation of the surprising results of the MIT FEL experiment.
Concurrently, he set up a laboratory in Taiwan, where he and his students embarked on experimental research addressing the key physics issues of the gyro-TWT. The culmination of the Taiwan group’s research has been the award-winning work on the fundamental stability properties of the gyro-TWT as reported in the 1995 and 1998 Physical Review Letters “Stabilization of Absolute Instability in the Gyrotron Traveling Wave Amplifier” and “Ultra High Gain Gyrotron Traveling Wave Amplifier.” This work made possible the experimental demonstration of a gyro-TWT with a stable gain of 70 dB, 30 dB beyond that previously achieved. This demonstration significantly extended the state-of-the-art of millimeter-wave gyro-amplifiers, thereby opening up new possibilities in communications and radar applications. His group’s most recent theoretical and experimental research has been on the electron cyclotron maser interaction involving backward waves (gyro-BWO). This has led to the revelation of a unique feature of this device, nonlinear field contraction in the saturated stage.
Kwo Ray Chu is the author or coauthor of over 100 scientific papers, 3 book chapters, and 9 patents. He has received the Publication Award, the Invention Award, and the Special Achievement Award from the U. S. Naval Research Laboratory, and the Outstanding Research Achievement Award from the National Science Council, Taiwan. In 1997, he was awarded the title of National Chair by the Ministry of Education, Taiwan. He was elected Fellow of the American Physical Society in 1983 and elevated to Fellow of the IEEE in 1997. He is the 2001 recipient of the K J Button Medal and Prize administered by the British Institute of Physics.
Kwo Ray Chu can be reached at the Department of Physics, National Tsing Hua University, Hsinchu, Taiwan; Phone: +886 3 571 0712; Fax: +886 3 572 3052; E-mail: krchu@phys.nthu.edu.tw .
This article was prepared by N. C. Luhmann Jr., Department of Applied Science, University of California, Davis, CA 95616; Phone: +1 530 752-5414; Fax: +1 530 754-9070; E-mail: ncluhmann@ucdavis.edu .