'A Vastly Superior Tool'

How teams led by Grainger Engineers Bill and Frank Fry, Floyd Dunn, and Bill O’Brien brought medical ultrasound into the world.

Spring 2022

When Bill and Frank Fry joined the electrical engineering department in 1946, space was tight. Even the worst space imaginable -- a steam tunnel under the building that housed the department -- was crammed with instruments that dated back to the war. The first world war, that is, almost 30 years prior.

Bill Fry (right) and Frank Fry
Bill Fry (right) and Frank Fry

Assigned two small offices and no lab space, the Fry brothers adopted that steam tunnel and sent the old equipment to be scrapped. It didn’t win them many friends among faculty, according to electrical engineering professor Floyd Dunn, who arrived at the University of Illinois as an undergraduate the same year as Bill and Frank Fry. 

The bold move of tossing long-unused oscilloscopes on the trash heap did, however, give them room to set to work. They stooped as they went from desk to lab bench because of the pipes overhead. Despite the limitations, they designed, built, and tested some of the first technologies for using ultrasound in medical diagnostics and surgery.

“They wanted to study the central nervous system with sufficient comprehensiveness to begin to understand intimate details of structure and function. The methods employed up that time had been rather crude, requiring invasion of brain tissues by physically rigid electrodes and the consequent production of unreasonably large lesions. Such methods were employed with the hope of identifying those structures, which might involve particular types of neural activity.” 

“Bill envisioned that ultrasound, which he knew could be focused to very small volumes, would comprise a vastly superior tool, by providing for noninvasive alteration of brain tissues,” Dunn said in a history he compiled before his death in 2015.

Floyd Dunn
Floyd Dunn

“He set out to deal with two related topics: Firstly, to develop ultrasonic surgical procedures for effecting the mammalian brain, both reversibly and irreversibly, which would provide for animal experiments and clinical surgical procedures and secondly to study the detailed neuroanatomy of the mammalian central nervous system, if you will, to determine a complete ‘circuit diagram’ of the neural components. The first of these was accomplished with extreme success and by the late 1950s had been well demonstrated in animal experiments and was being utilized in medical practice in a cooperative program at the University of Iowa. Numerous patients were treated for hyperkinetic and dystonic disorders, including Parkinson's Disease and intractable pain. The procedures, though extremely complex, were successful and Time Magazine discussed these in 1957.”

By 1957, Dunn was also leading groundbreaking research in diagnostic ultrasound. He and his team were particularly focused on how ultrasound propogates in the body, looking at sound’s speed, absorption, attenuation, scattering, and impedance through biological material. The Fry and Dunn labs were also studying the physical mechanisms behind those features.

“Throughout the approximately 20 year period from the mid-1940s to the mid-1960s...measuring methods as well as instruments were invented and developed to their full usable potential that are still employed throughout the world,” Dunn said.

Grainger Engineers, in other words, were moving a technology that is now synonymous with mothers and babies out of its infancy and into the world. 

One of Floyd Dunn’s graduate students, Bill O’Brien was key to that process. After earning a PhD with Dunn, O’Brien joined the federal Food and Drug Administration just as it was granted the authority to look into the safety of medical devices in 1971.

“Before the early ‘70s, it was the wild, wild west,” O’Brien said in a recent interview. “There were no federal guidelines on safety or the output of the devices that companies were making.” 

People were -- rightly, as it turned out -- worried by the amount of radiation emitted by color TVs, according to O’Brien. Unregulated x-ray machines let people get a look at their feet inside their new kicks at shoe stores across the country. Navy sailors were developing cataracts at higher rates because of their exposure to radar and microwave systems. 

Ultrasound, meanwhile, had been used by physical therapists to deep-heat muscle tissue for decades, but they “relied on the ‘ouch’ test. If a patient said ‘Ouch!’ then they’d back down the power a bit. They knew nothing about what the heating was, the energy levels. They really didn’t know anything,” O’Brien said.

Ultrasound lab
Ultrasound lab

The Fry brothers’ and Dunn’s work -- along with a small group of colleagues at MIT and in London -- had shown what was possible and where the basic thresholds for damaging tissue were. O’Brien helped launch an in-house ultrasound research group at FDA and used that work from his predecessors on an ongoing basis. 

That FDA team’s studies of pregnant mice, among other projects, served as a basis for Congressional legislation that gave FDA regulatory responsibility for medical devices in 1976 and, ultimately, led to the first FDA regulations on the safety and efficacy of ultrasound. It also helped massively reduce doctor’s reliance on pelvimetry, or x-rays of a mother’s pelvis during pregnancy. Ultrasound is regularly used today in fetal health monitoring, echocardiograms of the heart, guided biopsies and breast exams, and the visualization of blood vessels and organs. 

“Bill and Frank Fry and Floyd Dunn -- those teams, those people -- they showed us what was possible,” said O’Brien, himself a Donald Biggar Willett Professor Emeritus in The Grainger College of Engineering. “They wound up providing the benchmarks, designs, and technology for all the initial safety regulations.”