Congratulations to Dr. John Schenck, the first inductee into the GE Reports Genius Hall of Fame, which recognizes the most seasoned innovators at work creating world-changing technology at GE.
Dr. Schenck was a member of the GE research team that first developed the clinically viable Magnetic Resonance Imaging (MRI) scanner. Unlike x-ray or CT scans, which use ionizing radiation, MRI employs a powerful magnet to induce hydrogen atoms in the human body to emit radio signals, which it then interprets to construct a diagnostic 3D image of virtually any part of the body. Since then, more than 500 million MRI images have been made.
Dr. Schenck spoke with GE Reports about his experiences on the pioneering team, and shared his perspective on the role of medical imaging technology in the future.
A brave volunteer participates in a test conducted by Dr. Schenck and a colleague in 1983.
GE: What was your role in developing the first MRI scanner?
In the 1970s, and early 1980s, computed tomography (CT) had just become a very major business. GE had come from pretty far behind in that new modality and was just starting to take a leadership position.
Once I finished medical school, my main opportunity at GE was with a new modality, magnetic resonance imaging. It did sort of the same thing that CT did in that it made cross-sectional images of the human body, but using a completely different technology. It was considered very far-out because it required putting large magnets, which didn’t even exist at the time, into hospitals.
After some initial evaluations, we proposed buying a magnet that would be operated at 1.5 tesla, which is about 30,000 times as strong as the earth’s magnetic field and at least five times as high as anyone had previously used for whole-body human imaging.
Nuclear magnetic resonance (NMR) had been done in test tubes by chemists for a long time before we got involved, and so our job really was to scale it up to be used on entire human beings. It wasn’t obvious at the beginning that it was going to be possible to do at a price that anybody could afford.
We went through a lot of back-and-forth as to whether we should try to do research at this high field strength, or work at a much lower field strength, where the risks were a lot lower but where the NMR signal was much smaller.
GE: The risk of damage to the patient, you mean?
Oh no — the risks of trying a much higher, and unproven, field strength. There was a belief at that time that if we went to this high field strength — 1.5 tesla — that would mean we would be trying to take signals out of human beings at 63 MHz — which is a high frequency.
Some theorists said that signals that high would not pass through the human body, so we wouldn’t be able to get a signal from inside of people at this frequency. But there are many advantages to going to high-field strength if it will work.
With support from GE, management, we went out and contracted for a one-of-a-kind magnet from a magnet supplier in England, who built the magnet over a period of 1.5 years. When we got it back, we found that the early theory that it wouldn’t work at this field strength was wrong.
GE: So you were the first team to use those huge magnets for MRI?
Yes, we were the first team. There were technical difficulties, but we finally got it all to work in the middle of the night one night. I was the first person to be imaged with this device. We took an image of my brain as a first step. We expected there would be a big black spot toward the center of my head where this absorption we had theorized about was going to occur, but there wasn’t any — the whole image was there. Subsequently, 1.5 tesla became the gold standard field strength for all of MRI — from about 1983 until the present.
GE: What were you thinking at the time? Were you scared?
Oh no, I was trained as a physician and I approached the magnet slowly to see if any problems occurred. Also, a nurse had come down the first day I went into the magnet, and she had taken my blood pressure and pulse rate and everything seemed to be working fine. So I wasn’t afraid.
GE: You’ve also worked in the emergency room.
For something like 10 years — I worked as an ER doctor. I treated several thousand patients on the weekends and nights, but I was able to keep my full-time job at the GE lab during those years. It kept me in contact with patients and kept my clinical skills sharp, and allowed me to have valuable experiences with my medical colleagues.
GE: What are you most interested in at the moment?
My personal enthusiasm right now is for the new applications in brain imaging. Right now I would guess that we are only making medical use of a fraction — maybe 30 percent — of the information that is in our brain images. This is particularly true of functional MRI (fMRI), where you can actually see the brain going through the thought processes and see differences between different people and their responses.
We’re mostly interested in it in terms of its impact on disease, but there are all sorts of other potential uses of fMRI. There is neuro-marketing — imaging people’s brains and seeing how they respond to various advertising approaches. There is talk about using it in legal systems to evaluate whether someone is telling the truth or not using fMRI.
GE: Do you think the implementation of technology can help ease America’s health care woes?
It’s true that medicine is about a lot more than technology. But yes, I think there’s still a lot of opportunity for technology to contribute to health care. If you look around and say what’s our hope for treating depression? What’s our hope for treating stroke, or Alzheimer’s, or schizophrenia? Then I think it’s technology. One key to advancing this is in making the MRI more available — by reducing the cost of the scans and the scanners so there are more scanners in more locations — more readily available to doctors and patients. Smaller, specialized scanners for specific regions — such as the head only — will lower the barriers to using MRI.
