Paul Lauterbur and the Invention of MRI

by M. Joan Dawson

  Figure 2.4

  The shy high school boy graduates. Photograph from The Yellow Jacket: Year Book of Sidney High School, Class of 1947, Sydney, Ohio.

  The next year, Paul sat for an exam for the Prize Scholarship given at Case Institute. This was a big deal. Paul had to stay overnight at the local chapter of his father’s old fraternity. Incredibly, he somehow overslept the next morning. He dashed to campus just after the exam had started and was refused admittance. Finally, it was decided that he could begin taking the exam at the first break, while the others went outside to stretch their legs after finishing the mathematics section. He was allowed to remain in the exam room during later breaks to catch up, though the proctors worried that he might somehow learn from the others the answers to that first section. He wound up placing first, and was awarded one of five scholarships on offer.

  Spiritual Shift

  As a young adult, at an age when people question themselves closely about their beliefs and philosophies of life, Paul moved away from the family’s Catholicism. He remembered no spiritual crisis, but while in high school he came to realize he could not be a Catholic. This was driven by an intellectual rigor that says, I believe in reason, not in creation myths. He found Catholic doctrine in some cases offensive. If only Catholics are destined for heaven, as the dogma of the time still held, how could God have created so few of them among the billions of people who have walked this earth? He could no longer tolerate “the stupidity of teachings that held killing of a man to be morally equal to eating meat on Friday or missing Sunday mass.”

  Falling away from Catholicism was the greatest sin he could commit in the eyes of his family and the Church. To them, it meant losing his soul. Out of respect for his parents’ feelings, Paul kept his opinions to himself, and on his weekends home from college he knelt with the family for lengthy repetitions of the Rosary.

  Paul became an atheist, revering intellectual honesty and the quest for truth. He believed that reason is the crowning achievement of the human mind; it is meant to be used and, like muscles, to be strengthened with exercise. He made it his lifelong pursuit to discover laws of nature.

  3

  Study, Work, and War

  Like all other arts, the Science of Deduction and Analysis is one which can only be acquired by long and patient study.

  —Arthur Conan Doyle

  In 1947, Edward’s advice to his college-bound son was to enroll as an engineering student. “Dad didn’t know what a scientist could do,” Paul said, “but there was always work for an engineer.” So off he went to the engineering program at Case Institute of Technology in Cleveland, now a part of Case Western Reserve University. The move was from village to city, from the southwest to the northeast of his natal state, to the shores of Great Lake Erie. He was still an erratic student. Irvin Krieger, a professor at Case, put it this way: “Lauterbur was a bright Case undergrad who refused to let his course work get in the way of his education.”1 Paul entered this curriculum as a bright young man and left it, he felt, fully prepared to make his mark in the world.

  Lauterbur fils followed Lauterbur père as a member of the local Phi Kappa Tau fraternity. This may have been the unofficial Hobart Inc. fraternity, since many of Paul’s frat brothers were sons of Hobart men. Fraternity life was especially interesting in those days since the brothers came in two flavors: boys like Paul fresh out of high school, and mature men returning to school on the GI bill after World War II. One was a traumatized war vet with a terror of bugs. When he saw one he would jump on top of his desk and call for his 9 iron. He’d try to bash the bitty bug with his golf club. The younger boys got a quick initiation into the ways of older men, gambling, drinking, and engaging in other pursuits of which they did not inform their mothers. The older men struggled to get back into academic habits.

  When I heard the Case fight song—“e to the x, dy/dx, e to the x, dy / Cosine, secant, tangent, sin / Come on team, let’s hit that line!”—I knew their football team was no good. Bill Kerslake (later of the National Advisory Committee for Aeronautics, the predecessor to NASA) was one of their athletes. Bill was a chemistry/chemical engineering major, a Greco-Roman wrestler (no attacks below the waist), and a member of the football team. If there was a conflict between football practice and chem lab, he went to chem lab. Kerslake was a heavyweight wrestler who won fifteen national championships in a row, and a gold medal in the 1955 Pan American Games.

  Paul enjoyed fraternity life, with some reservations. Many of his brothers and fellow engineering students were not there to become engineers. They made no secret that their goal was to be out of the laboratory and off the shop floor as soon as possible so that they could step into what they hoped would be lucrative desk jobs. Many of them strode this career path very successfully, but the attitude pained Paul, who had such an earnest craving to understand science and technology.

  When did the faculty begin to know that their new student was not quite like the others? There was an early hint at the departmental Christmas party. Chemists can certainly be odd. The party game was to sniff at various concealed chemicals placed around the room; the person who identified the most chemicals by smell was the prizewinner. The award went to a graduate student whose research work was on the smells of chemicals. The freshman Paul Lauterbur came in second, and the head of the department was third.

  Paul signed up for organic chemistry in the fall semester of his sophomore year, after taking the introductory chemistry courses in his freshman year, still a typical sequence and timetable. Untypically, though, he found a chemistry textbook and studied it over the summer. It turned out to be the same one used in the organic chemistry course; he had already learned all of the material for both the fall and spring semesters. He took a placement exam and was exempted from the second semester, substituting a graduate course in quantum chemistry. Now very interested in chemical sciences, he changed his major to this field. Paul never did fulfill the engineering requirements, and although the Institute of Electrical and Electronics Engineers claims him as one of their own,2 and Rensselaer Polytechnic gave him an honorary doctorate, Paul never qualified as an engineer.

  As a junior, almost as if he had a premonition of his future, Paul studied magnetism. He discovered and studied a published method of measuring magnetic susceptibilities.3 Irvin Krieger, the Case professor, remembered this student project more than half a century later: “For his P Chem. lab project, Paul decided to measure magnetic susceptibilities. However, suitable equipment was lacking—all he had to work with was an outdated analytical balance and a war surplus magnetron magnet. To make the task more difficult, the physical chemistry laboratory was only one floor below the Smith Building’s ventilating motors, whose vibrations make measurement tedious and imprecise. Paul solved the problem by working at night, when all the ventilators could be turned off.”4 He would move the tabletop magnet so the poles were across capillaries containing different solutions of paramagnetic ions (charged particles that have very high magnetic susceptibility) and measure the effect. It worked, but one result he noted always eluded him. Every other rise in the capillary fluid was a little higher or a little lower than the preceding one. Probably some sort of surface tension effect, but he was never able to find out why, which nagged him for the rest of his life.

  For Paul’s senior thesis, he intended to do publishable research. Carbon and silicon are closely related atoms, so closely related that for years, chemists (and at least one middle school student) wondered why life is based on carbon and not on silicon. Paul studied both of them in his home laboratory while in middle school and high school. An important difference between these two atoms is that compounds in which carbon binds to itself (C–C bonds) are extremely stable. For example, methane, methyl alcohol, and the amino acid glycine all contain carbon bonds; all are common in living organisms; all have been made by common chemical methods; and all hung around in the oceans and in the Earth’s early atmosphere for millennia. From these small, stable carbon compo
unds and their products the polymers of life are built (DNA, complex carbohydrates, and proteins).5 The analogous silicon compounds (Si–Si bonds) are unstable, much rarer in the environment of the Earth, and practically nonexistent in biology. There are no comparable stable silicon polymers in living organisms.

  “What” Paul asked himself, “would happen if the bond was C–Si? Would this compound be stable or unstable?” So he set out to synthesize such a compound and study its reactivity, having found no published work on this project.6 An indulgent professor, Aaron Nelson, an organic chemist who specialized in natural products, was somehow induced to mentor Paul for this adventure, allowing his student complete independence but no guidance. A student who strikes out into the unknown like this learns a great deal but rarely accomplishes much because the project is always harder than anticipated. And so it happened to Paul. He redeemed himself by putting in a great deal of experimental effort and a great deal of thought as to what went wrong and what further experiments might usefully be done. (Chemistry of the day could not explain Paul’s results; today we probably could.) Professor Nelson must have marked the high quality of the work and hoped for great things in his future. Paul’s own assessment was, “I got some fancy colored stuff, but never settled the question.”

  Figure 3.1

  Paul’s C–SI compound.

  During his senior year, Paul also began taking graduate-level courses. He had already marked his interest in creating physical and chemical methods and in using these for understanding the nature of our world. The famous accomplishment of his mature years, MRI, is an expansion and transmogrification of the thinking and work he had already done by his senior college year.

  Yes, he had a private life. “Girls came and went,” he said, as if they were of no consequence. During summers, Paul worked as a laboratory assistant at Hobart, his father’s company, performing routine analyses for the metallurgical control of the foundries. The bachelor of science degree was conferred on Paul and 321 classmates in June 1951.

  Figure 3.2

  College graduation picture, 1951.

  By his senior year, Paul “had had it with classes and lectures and all of that formal learning.” This is why he didn’t even consider going into graduate school to pursue a PhD—that, and he was simply unfamiliar with it; the world of postgraduate academia was beyond his ken. Case was an engineering school, and since it has always been most common for engineering students to go directly into industry after college, that’s what he did. In those years Dow and Dow Corning, both based in Midland, Michigan, hired many of their young workers from Case.

  For the Love of Silicon

  Dow Corning, an offspring of Dow Chemical Company and Corning Glassworks, was then very young. The original collaboration between the parent companies arose because a Corning researcher had succeeded in using glass rectangles and squares to build up grand walls of glass that allowed sunlight into interior spaces as never before. Mid-century architects of the organic movement loved it. But Corning needed a better resin, something strong and transparent, with improved adhesion, to join the glass segments. Thinking that combining glue (organic, carbon stuff) with silicon (the primary element in glass) might work, a fellow at the Mellon Institute in Pittsburgh working with Corning developed a silicone (a polymer of silicon) resin that had some of the required properties. It was natural at this point that the researchers collaborate with Dow, a company with knowledge about the atom silicon and the polymer silicone and easy access to starting materials.

  Dow Corning launched some breath-taking innovations in industrial chemistry. The element silicon is really quite special; it may now be best known for the silicon chips that go into the microprocessors that control our dishwashers and washing machines and, increasingly, our cars. They are also the guts of our computers. Or it may be more familiar in the name of Silicon Valley, near San Francisco, long the incubator of computer technology. But in prehistory (the mid-twentieth century), organic chemists, not techies, were fooling around with this sister element of carbon. They sought to do what nature could not: synthesize large stable polymers of silicon, analogous to the organic polymers of life. Silicone, a polymer made from silicon, oxygen, and hydrogen atoms, was an important product of their efforts; it is a magnificent sealant whose uses continue to expand to this day.

  Once Dow Corning started putting silicon polymers together, enchantment ensued, and wonderful new materials came forth. The first commercial product had nothing at all to do with glass. It was an ignition sealant for aircraft engines, invented by Earl Warrick, for whom Paul would later work. Dow Corning produced and marketed its silicones in industries from bread baking to electrical insulation. “Silicone” and “Dow Corning” became practically synonymous (with a nod here to GE, which was a close competitor but had a much broader portfolio). The company grew explosively in its first seven years. The age of silicone had arrived.7

  A chemist can fall in love with an atom or molecule in the same way a poet can fall in love with a sentiment or a turn of phrase. Carbon and silicon, cunning atoms, were Paul’s long-standing intellectual sweethearts. Carbon builds molecules so fruitfully and with such multiplicity; all of biology exploits the flexibility of carbon bonding. Carbon “wants” to bond with other atoms, especially with itself, oxygen and hydrogen, and does so easily in the natural world. The bonds are stable in our watery selves, a necessary condition for our existence. Silicon is carbon’s lower neighbor in the fourteenth column of the periodic table, so placed because it has many of the same characteristics and makes the same bonds as carbon. But silicon is both wilier and more unruly.8 You do not see in nature long chains of silicon analogous to chains of carbohydrates or DNA. If that were possible, the very sands (silicates) would procreate. The instability in water of silicon bonds makes silicon hard to work with, both for the chemist and for nature. The Dow Corning chemists knew that making stable long-chain silicon compounds would be both difficult and very rewarding. You have to push silicon a little, but once you do the effect is magical.

  These pioneers hardly knew what properties to expect as they systematically went through the synthesis of possible silicon polymers. It is impossible now to enumerate the importance of silicones to the functioning of modern society; like plastics, silicones are everywhere—sealing, bonding, and coating the products of everyday life. Paul shared the excitement of the early researchers at Dow Corning. They were making artificial rubber, using silicon in the place of carbon. Polymer chemistry was only beginning to be understood, and Paul had already explored this new science in studies of rubber in his home laboratory; he also knew something about silicon chemistry.

  In his senior year, recruiters from Dow Corning came to campus. Perhaps recognizing Paul’s potential as a scientist, Dow Corning hired the young Lauterbur and assigned him to work at their Mellon Institute Research Group in Pittsburgh rather than sending him to their production plant in Michigan. The environment at Mellon was more academic than corporate. So Paul moved some 130 miles from the flats of Lake Erie in northeastern Ohio to the northernmost hills of Appalachia, where he would make his home for a dozen years. Though Pittsburgh occupies one of the loveliest sites east of the Mississippi, on hill country overlooking the Monongahela and Allegheny Rivers, the city once had some of the worst living and working conditions America has ever seen. The coal-fired steel plants belched flame and soot; the skies were black at midday. The city was once known as “hell with the lid off” and its politics as “hell with the lid on.”

  When Paul arrived in 1951, Pittsburgh was acting on its postwar plan of a major renaissance, cleaning itself off. He watched as buildings were scrubbed of their grime, the white Pennsylvania stone finally revealed. The research group Paul joined was headed by a senior biochemist, Rob Roy MacGregor. His assistant was the now well-remembered synthetic organic chemist Earl Warrick. Earl’s greatest achievement was the invention of silicone rubber, finally accomplishing what nature could not, the stable long-chain silicon polymer on
which much of modern technology depends. But his most famous achievement was the accidental discovery of Silly Putty! The researchers kept this material in their labs and offices for months while trying to think of a way to make money on it. “We . . . took advantage of its unique properties to astound visitors by bouncing it off the ceilings and walls of our laboratories,” Earl remembered.9 Finally, they decided it was a toy, the first product Dow Corning marketed to individuals instead of for commercial use. Paul’s intellectual milieu was now bursting with silicates, silicones, siloxanes, sylazanes, and sylastics. As a child growing up in Midland, where Dow Corning did its main manufacturing, I knew when they were making a batch of product because the air turned green and smelled funny. So I too breathed this chemical poetry and pollution.

  Figure 3.3

  Paul specialized in sticky gooey messes. He thought a lot could be learned from these about polymer chemistry. © 1979 The New Yorker Magazine, Inc. Reproduced by permission.

  The administrative plan at the Mellon was a fellowship system devised by Robert Kennedy Duncan, the industrial chemist and educator. A firm would hire the Institute to solve a specific problem; the Institute would then hire an appropriate scientist (fellow) to do the research. All results were the property of the contracting firm. The system was so successful that it eventually self-destructed, with the companies in the chemical industry able to set up similar research facilities of their own.