In Memoriam – Robert F. Wagner

Robert F. Wagner died from prion disease on June 30, 2008. During more than forty years of his professional life, he made many contributions to the field of medical imaging and had a significant impact on academia, industry, and regulatory science. He has more than 160 publications, many of which are highly cited.Bob was born in Philadelphia, PA in 1938. He received his BSEE as valedictorian from Villanova University, Philadelphia, PA in 1959. He served in the Order of St. Augustine, Washington, D. C., from 1959 to 1965. He received his MA in Theology from Augustinian College and MS in Physics from Catholic University, Washington, D. C., in 1965. He received his Ph.D. in Physics from Catholic University, Washington, D. C., in 1969. He served as a post-doctoral research associate at Ohio University in 1970. He worked at the Bureau of Radiological Health (which later became part of the Food and Drug Administration Center for Devices and Radiological Health) from 1972 until 2008. He was a fellow of the IEEE, the Optical Society of America (OSA), the Society of Photo-Optical Instrumentation Engineers (SPIE), the Society of Professional Scientists and Engineers (SPSE), and the American Institute for Medical and Biological Engineering (AIMBE).

Bob is probably best known to the medical ultrasound community as a co-author (along with Stephen W. Smith, John M. Sandrik and Hector Lopez) for a pair of papers, "Statistics of Speckle in Ultrasound B-Scans," and "Low Contrast Detectability and Contrast/Detail Analysis in Medical Ultrasound," Vol. SU-30, No. 3, pp. 156 - 163, and pp. 164 - 173, 1983, that collectively received the award for best paper in IEEE Transactions on Sonics and Ultrasonics (now IEEE Transactions on UFFC). These articles are classic references in medical ultrasound. In the former paper, which has been cited 338 times (according to Web of Science), the authors calculated the relationships among ultrasound speckle spot dimensions, tissue microstructure, and imaging system characteristics. They validated their theory with measurements on a tissue-mimicking phantom. Their analysis took a very complex subject and made it tractable. It provided many insights that went on to guide subsequent work on compounding, multi-aperture parallel acquisitions, and phase aberration correction. These constitute some of the basic components of receive beam formers found in modern clinical ultrasound imaging systems.

Bob’s other work in medical ultrasound included combining advanced models for acoustic scattering with statistical models to enable estimation of scatterer size and spacing from moments of the echo spectrum, even when scatterer size is much smaller than the diffraction limit. Bob also worked in demonstrating the value of autoregressive spectral estimation for ultrasonic tissue characterization. Bob’s work in data fusion in tissue characterization had great clinical relevance. He was a co-author on a paper (B. S. Garra, M. F. Insana, T. H. Shawker, R. F. Wagner, M. Bradford, and M. Russell, “Quantitative Ultrasonic Detection and Classification of Diffuse Liver Disease – Comparison with Human Observer Performance,” Investigative Radiology, 24, 196-203, 1989) that won the 1990 Herbert M. Stauffer Award for best clinical paper award in Investigative Radiology.

Bob also made many important contributions to x-ray medical imaging, as evidenced by his election to Fellow in SPIE. In fact, the 2009 SPIE Conference (February, Orlando, FL) will be dedicated in honor of Bob and Bruce Hasegawa. The annual Conference on Ultrasonic Imaging and Tissue Characterization (May, Arlington, VA) will also be dedicated to Bob.

Beyond his scientific accomplishments, Bob was a dedicated mentor and a good friend to all three of us. He was always willing to spend generous amounts of time with each of us to answer our questions, to collaboratively develop scientific ideas, or to exchange jokes. With his great sense of humor and his ability to identify fruitful avenues of investigation, he made scientific research fun and stimulating. We will miss him greatly.