William Oldendorf

Inventor of computed axial tomography helped move brain diagnostics out of the dark ages
01 January 2022
By William G. Schulz
William H. Oldendorf with his prototype CT scanning device.
William H. Oldendorf with his prototype CT scanning device.

Nobody is recognized for having almost won a Nobel Prize. Well, no one, perhaps, except William H. Oldendorf, a pioneering neurologist and medical device inventor at the University of California, Los Angeles medical school and the Brentwood Veterans Administration (VA) hospital.

Oldendorf was indisputably an early developer and inventor of computerized axial tomography, aka the CAT scan. But despite his patent of the first CT scanning device, which was backed by published research, the 1979 Nobel Prize in Physiology or Medicine was shared only by Allan M. Cormack and Godfrey N. Hounsfield "for the development of computer-assisted tomography." Oldendorf, it is said, was dropped from the list in a last-minute decision by the sages of Stockholm.

In a gossipy 1980 essay about the ensuing outrage among Oldendorf supporters, science writer William J. Broad reported that "Reasons given for the omission of Oldendorf include consideration by the Nobel Assembly of the effect that awarding the prize to two Americans and one Englishman [Hounsfield] would have on the multimillion-dollar litigation of patent rights now underway between US and British manufacturers of CAT scanners. Another is discrimination against a physician-clinician by the basic science faction of the Nobel Assembly."

Prize or no prize, Oldendorf, who came to be known as the Thomas Edison of medical device innovation, created a truly revolutionary new method for brain imaging, which he patented in 1963. As he described his original idea, the machine would emit a collimated high-energy beam of photons from a source, on one end of a fixed arm, with a detector sitting directly across a gap. A patient's head would be placed in the gap, that is, the beamline, between source and detector.

"These photons are directed through the [subject's head] and, by virtue of their removal from the beam, map the internal structure," Oldendorf wrote in a 1978 review paper in Neurology describing his invention. "The procedure is similar to shadow radiography but film is replaced by an x-ray detector and the moving narrow beam of x-rays permits a point-by-point plot of the transmission of the object."

Oldendorf's inspiration for CT scanning was the result of an intuitive leap driven by his passion for replacing some of the most traumatic and invasive procedures of mid-20th century neuromedicine.

In the review paper, he describes a social gathering some 20 years earlier at which one engineer sought advice on devising an x-ray method for rejecting frostbitten oranges at harvest.

"Of course, it's much too expensive to radiograph every orange," writes Oldendorf. "The engineer was working on an automated method in which he proposed to allow oranges to roll, one at a time, through a beam of x-rays...it occurred to me that it might be possible to consider the orange analogous to a head and the dehydrated spots to internal structural details of the brain."

Today, thanks to Oldendorf and others who would further develop CT scanning and other brain imaging modalities, such chilling words as "exploratory surgery" and "carotid angiogram," which involves a needle and that artery, have hit the medical discard pile.

In the 1961 paper describing the first experimental CT scanning device, Oldendorf writes about his motivation: "Each time I perform one of these primitive procedures I wonder why no more pressing need is felt by the clinical neurological world to seek some technique that would yield direct information about the brain without traumatizing it."

Oldendorf’s prototype CT scanner

The Oldendorf's prototype CT scanner used nails to represent internal structures in the brain. Credit: Courtesy of the Veterans Administration

For a complete scan, Oldendorf added to his experimental device rotation of the beam source and detector around the subject. He writes, "For simplicity I originally kept both the source and the detector stationary and created the necessary relative motions by moving a cranial model. This model of the head consisted of two rings of irregular iron nails (to simulate the skull) with an iron nail and an aluminum nail near their center (to simulate intracranial structural details)."

Other materials Oldendorf used in his experimental device included plumber's lead, melted on the kitchen stove, and an H-O gauge train flatcar and track borrowed from his son. He describes a tour-de-force of American garage-style innovation:

"The entire model was then mounted on a 16 rpm phonograph turntable in such a way that the axis of rotation of the turntable intersected the beam of gamma rays. Pulling the flatcar along the track was a radio-receiver-dial string assembly, connected to a pulley that was in turn attached to a discarded spring-driven alarm-clock motor. This apparatus moved the point of intersection of the axis and the beam through the model at 80 millimeters per hour."

A year after Oldendorf published his review paper, the Nobel Committee reached its decision, the details of which have probably gone to several graves by now. In his essay, Broad suggested another, more subtle reason Oldendorf may have fallen off that year's prize list at the last minute:

"Conspicuously absent from Oldendorf's original paper is mention of mathematics. Instead of a computer, he used a circuit to reconstruct internal points from the hypothetical patient's head." The idea being that it was Cormack and Hounsfield's precise mathematical constructs for planar imaging of the brain that made CT scanning practical and marketable.

Upon learning that Oldendorf did not share the prize for his pioneering work on CT scanning, physicist and Nobel Laureate Rosalyn Yalow, was quoted as saying, "The only thing that will make it up is if he gets another money award. But you don't go down in history with money. You go down with a Nobel."

Oldendorf did win many prizes over the course of his distinguished career, and he was nominated for the Nobel by Yalow. His research included pathbreaking studies of cerebral metabolism and the biomechanics of the blood-brain barrier. In 1975, he was awarded with Hounsfield—who he always credited with further innovation that would make CT scanning a workhorse medical device—the Albert Lasker Clinical Medical Research Award, often called the American Nobel. And in 1976, he was recognized for his "development of nuclear techniques in clinical neurology," which includes CT scanning, with the VA's prestigious William S. Middleton Award.

In a tribute to Oldendorf, shortly after his death in 1992, a colleague recalled him as "immediately likeable, friendly, and extremely amusing. His ability to apply techniques from one field to another was uncanny."

L. Jolyon West, then chairman of psychiatry at UCLA wrote, "Bill's mind was Einstein's universe, finite, boundless. Always reaching into spheres you wouldn't imagine."

WILLIAM G. SCHULZ is the Managing Editor of Photonics Focus.

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