History

In the annals of medical physics at UW-Madison, a remarkable chapter unfolds—the story of ultrasound research. Dr. Charles Kelsey, a nuclear physicist by training, embarked on a journey that would forever alter the landscape of medical imaging at Wisconsin and beyond.

Dr. Charles Kelsey: A Visionary Transition

Dr. Kelsey’s trajectory began with nuclear physics, but destiny nudged him toward a different path. In 1965, he joined the Department of Radiology at UW-Madison, under the mentorship of Dr. John Cameron. The mission? To expand medical physics activities and explore uncharted territories: ultrasound.

Dr. Kelsey and his team—self-described as “tinkerers”—set the stage for groundbreaking research. Within a year, they amassed an eclectic collection of ultrasound devices. From a 2.4 MHz physical therapy unit to a Magnaflux continuous wave Doppler device, their arsenal grew. But skepticism loomed large.

Ultrasound’s Underestimated Potential

In those early days, few grasped the significance of ultrasound. An abstract submitted to the Radiological Society of North America met rejection. The reason? Ultrasound was deemed outside the realm of radiology, its role dismissed. Yet, Dr. Kelsey persisted. You can see an interview of Dr. Kelsey conducted by the very own Dr. John Cameron in 1994 on the AAPM history and heritage website:

Innovations Unleashed

Dr. Kelsey’s graduate student, Jim Zagzebski (who would become chair of the Department of Medical Physics), working with speech researcher Ken Watkin introduced “ultrasonic tongue beads” to study patterns of motion of speed organs. At the time, speech researchers were adhering x-ray-opaque beads to the surface of the tongue. Ken Watkin was hired by Chuck Kelsey and his speech and hearing department colleagues  to work on a grant involving use of ultrasound in speech research. The piezoelectric elements used instead of the radiopaque beads adhered temporarily to the tongue surface using a non-toxic dental cementing compound. A single-element transducer, positioned below the chin, emitted ultrasound pulses through the soft tissue. These pulses were detected by the piezoelectric beads after a delay proportional to the transducer-to-bead distance. Dynamic movement patterns of the piezoelectric element on the tongue surface were meticulously tracked using M-mode techniques. By comparing the bead’s motion path to tracings recorded via x-ray cine radiography, the accuracy of this method was convincingly demonstrated. The “tongue beads” technique allowed speech studies without subjecting patients to extensive ionizing radiation, eliminating the need for frame-by-frame x-ray measurements. In addition, Jim Zagzebski built a directional Doppler unit to also record vocal fold motion. The work continued mostly independently of Dr Kelsey after he started working intensely on a different project involving the neutrons. You can check the 1973 publication in the Journal of the Acoustical Society of America here:

Ed Cytacki, another graduate student working with Dr. Kelsey, constructed a contact scanner to replace the water bath scanners in use prior to that time.  The articulated arm system enabled 2-D scanning and effectively demonstrated to University of Wisconsin officials the potential of ultrasound for imaging soft tissues in the body. This led to the acquisition of an early commercial version of a “contact scanner” by the UW Hospital Radiology Department.  The Picker 80 L is a descendent of one of the first articulated arm scanners developed in the US at the University of Colorado and originally marketed by the Physionics Corporation. Picker purchased Physionics in 1967 and slightly changed the design of the system.

The unit was located in shared Medical Physics –Nuclear Medicine space in the Bradley building attached to the UW Hospital. Initially it was operated by Professor Kelsey and graduate student Jim Zagzebski. Later they trained x-ray and nuclear medicine technician Jackie Cassidy to do scans, and she became UW’s first full time ultrasonographer in the department of Radiology.

The unit used an exchangeable, single element piezoelectric transducer attached to the short arm of the 3-armed  tracking device. The angle of each arm was tracked by a series of wires and pulleys attached to a set of sine-cosine potentiometers in the scan console. This provided information on the x-y location and the exact orientation of the single-beam transducer which was operated in a pulse-echo mode.  Images were formed on a bistable storage oscilloscope screen, and hardcopy was obtained by photography.

Speech researchers also became fascinated with the 2-D scanning enabled by the articulated arm system. One of the potential applications was in scanning the human tongue. If the transducer is coupled to the skin surface at locations beneath the chin and aimed upward towards the top of the head, the tissue-to-air interface at the dorsal tongue surface provides a strong echo. Thus, it became possible to outline the posture of the tongue during static speech sounds by scanning the dorsal surface.  The speaker’s face could be outlined by simply translating the face of the ultrasound transducer over skin with the system sensitivity lowered so that no echoes were displayed.  With such a system, the configuration of this important speech organ during various utterances could be brought out.

Ultrasound in Treatment Planning

Ultrasound became indispensable in radiation therapy planning. Depth dose curves overlaid on B-mode images guided tumor localization. The Unirad Ultrasound scanner provided stability and precision. However, the rise of X-ray CT and MRI eventually diminished ultrasound’s role.

Dr. Kelsey’s legacy extended beyond physics. His vision, coupled with the ingenuity of Dr. Jim Zagzebski, shaped a new era—one where ultrasound illuminated the hidden contours of life.