Gilbert Fletcher and radiotherapy

By Bryant Boutwell and Charles M. Balch

He was born Gilbert Hungerford Fletcher in 1911, of an American father and French mother, and grew up in France and Belgium. He earned engineering and mathematics degrees from the University of Brussels and completed his medical degree there in 1941. His American passport proved essential for travel through German-occupied countries on his way to America for post-graduate training.

At the New York Hospital he was accepted into a radiology residency. He passed his boards in 1945 as Lee Clark was becoming a candidate for the directorship of MD Anderson. As an American citizen, Fletcher was drafted into the Army Medical Corps with post-war plans to specialize in radiology. His wife, a physician from Mississippi, heard Lee Clark was starting something special down in Texas and advised her husband to go find him.

What a sight Gilbert Fletcher must have been walking into Clark’s office at the Oaks, wearing his military uniform with a French beret perched on his head, with his English buried in the thickest French accent Clark had heard since his training in Paris. This unusual man, Clark learned, possessed an impressive knowledge base spanning Latin and Greek, civil engineering, physics, mathematics and medicine. Like radium, Fletcher was a bundle of stored energy bursting with ideas about treating cancer with radiation. It was music to Clark’s ears.

Clark immediately offered a year’s funding for Fletcher to travel Europe as a consultant learning all he could regarding how the power of atomic bombs could be harnessed for patient care. Years later Clark remembered the moment as “one of the best investments I ever made.”

By the time Fletcher returned from Europe in 1949, he had collected the lowdown on the latest and best ideas for treating patient with radiation. He also had the name of a physicist named Grimmett he met at Hammersmith Hospital in London. Clark hired Fletcher in 1949 and named him the institution’s first full-time radiologist. 

Dr. Leonard Grimmett arrived at MD Anderson in 1949. He was both brilliant and quirky according to early MD Anderson staff. In Houston he hoped to see grand boulevards and a magical river like the Seine. What he found was Buffalo Bayou.

“My first impressions of Houston and the hospital are not at all favourable [sic],” he wrote to his wife in Paris. “The town is full of shacks and people living in caravans [trailer homes].” 

What Leonard Grimmett lacked in admiration for Houston, he made up for with sheer brilliance. Years later Clark recalled, “He was absolutely the man for the job. … It was fantastic — the accumulated knowledge in that man’s mind and the way he could put it down.”

The key, Fletcher and Grimmett determined, was cobalt, not radium. Fletcher explained it to Clark in a 1948 letter from Europe.

“Radioactive cobalt could develop into a substitute for radium if it becomes much cheaper. The beta and gamma rays are of different energies and all of the dosimetry and clinical dosage radium work will have to be redone with cobalt with suitable filtering materials. … I cannot emphasize too much that this groundwork requires considerable experience and really adequate equipment, including the presence of an excellent workshop manned by good instrument makers.” 

Considerable experience meant adding a physicist like the fussy Grimmett, who got his physics laboratory workshop on the grounds of the Oaks after specifying the exact flooring he required. Fortunately, his precision translated directly to his work.

Clark did more than build a physics laboratory and workshop. He made plans to add a new Radiological Institute to his blueprints for the new hospital in the medical center. 

“We have requested for building a radiological institute and atomic energy research laboratories, an item of $1 million and $350,000 for equipment,” he wrote his boss, Dr. Theophilus S. Painter, president of The University of Texas. “As you recall, when this hospital was established by law in 1941, there was no such thing as isotope or atomic research in the biological fields as we now understand. Since Hiroshima, a new world in research and possible treatment has been opened to us. The citizens of Texas should have the opportunity to benefit by this new knowledge and we would propose to bring it to them through the establishment of such a program within our cancer hospital.” 

Fletcher and Grimmett were convinced that radiation treatment would benefit from the development of a more powerful and reliable energy source than the 250-kVp X-ray machines of the day. Megavolt X-ray machines and the Van de Graaff static machines were a decade old and would not do. They would design and build something better using cobalt-60, an artificial isotope with an energy of 1.3 MeV and a half-life of five years. Physics jargon aside, Grimmett went to work.

Originally, he had planned to use uranium, but it was stockpiled during the Korean War. The features of cobalt-60 included the low cost of cobalt compared to radium and the possible technical advantages that a cobalt source might offer in the design of a unit. They made no small plans and designed the unit around a 1,000 curie source, which was more radioactivity than all the radium in the world contained. It was a fantastic idea that would be a breakthrough if it could be done.

Then came a problem. The Atomic Energy Commission (AEC) turned down Clark’s initial proposal, declaring it as impractical as going to the moon. Not one to give up, Clark turned to a friend, Marshall Brucer, who hoped to get at job at the AEC’s Oak Ridge site in Tennessee. Brucer got the job and Clark got an appointment to Brucer’s medical review board. With an agreement to collaborate, MD Anderson got approval to proceed.

Then came funding problems. Clark got Glenn McCarthy, that Houston oilman who built the Shamrock Hotel, which opened in 1949, to organize a charity football game at Rice University’s stadium. The event raised $16,000. Every dollar helped. 

Then another issue arose. The cobalt disc had to be irradiated, and the U.S. atomic pile where that could happen was busy making atomic bombs. “So, we went to Canada,” Clark recalled. Fletcher had connections with Canada’s Chalk River atomic pile and was surprised to learn Canada had the same idea for cobalt-60. Long story short, the MD Anderson cobalt was irradiated to 800 curies. Canada later claimed to be first in the world with cobalt-60, but Clark maintained that “there wasn’t any doubt that Grimmett and Fletcher were first as far as the original concept and design are concerned.”

The plans for the irradiator head had been submitted to General Electric X-ray Corporation for quotations and fabrication, using tungsten alloy as hard as diamond and equally hard to fabricate. Sadly, only a few days before General Electric X-ray Corporation completed the unit’s fabrication, Dr. Grimmett died of a heart attack, on May 27, 1951, at age 49 ─ within 24 months of his arrival at MD Anderson. He never saw the product of his hard work.

Getting the irradiated cobalt out of Canada and back to Oak Ridge [for testing] was another challenge.

“We got the Northwest Mounted Police to ride shotgun on it coming down,” Clark recalled. “Everybody was all excited about this cobalt moving through the country. What would it do if it got stuck here or fell off there and broke? Would it blow up? Everybody was calling it the cobalt bomb.”

How did it work?  The unit involved a small pellet of cobalt-60 housed in a shielded rotating-head device with an aperture that could be adjusted to cover the size and shape of the patient’s cancer. The disk could be rotated by remote control so as to screen the cobalt-60 or to expose it. The radiation source was exposed through an aperture in the lower end of the cylinder to furnish a narrow gamma ray beam for treatment.

Back in Houston, Dr. Robert Shalek, who in 1961 became head of MD Anderson’s physics department, was busy conducting radiation protection measures. These studies, along with the handling of radioactive isotopes, were conducted in the basement furnace room of the greenhouse at the Oaks. As a result of these experiments, the design of the source wheel was altered to prevent radiation leakage when the unit was in the “off” position. Fabrication of the unit was already half-completed, but it was properly corrected.

By September 1953, the cobalt-60 unit was loaded into a truck trailer for the police-escorted 983-mile shipment from Tennessee to Houston. The unit arrived safely and was installed in the new hospital’s subterranean suite with concrete walls 6 feet thick. Cones and special attachments were fabricated in the physics workshop at the old Baker estate. 

What a momentous day Feb. 22, 1954, was for Clark and Fletcher as the first patients were treated with the cobalt-60 unit in the well-fortified new quarters of the permanent building. Patients were transported back and forth between the Oaks and MD Anderson’s cobalt-60 treatment room in the Texas Medical Center. A month later, all patients at MD Anderson’s temporary hospital were transferred to the permanent new facility.

By 1959, MD Anderson was a national leader in radiotherapy, treating about 90 patients a day with state-of-the-art equipment including two cobalt-60 units, a 9-ton betatron and a caesatron unit installed in 1957, with capabilities to rotate around the patient. The 22 million-volt betatron was one of the most powerful of all existing X-ray units, allowing greater penetration for deep-seated cancers (such as found in the gallbladder or cervix). The caesatron, then the newest of the units, used radioactive cesium in special cases such as postoperative breast cancer treatments requiring fast radiation penetration. MD Anderson’s radiation therapy capacity exceeded that of any other radiation department in the world at the time. 

With the thickest French accent this side of Paris despite living in Texas for four decades, Fletcher was a legend in radiology oncology. In 1955, he hired Dr. Gerald Dodd, who in time would assume departmental leadership. It was Dodd who took over diagnostic radiology duties, allowing Fletcher to focus on new instrumentation and techniques. One of the great teachers in radiation oncology, Fletcher also was a trendsetter who insisted his clinical staff specialize by cancer type. Dr. Eleanor Montague, for example, became a national leader as a radiology oncologist specializing in breast cancer. Fletcher died in 1992, ever dedicated to MD Anderson and his chosen field.

Important to note, when Fletcher first arrived in army uniform and beret, Lee Clark was on the front end of planning the new hospital. Just as deftly as he handled the financial and logistical challenges of cobalt-60, he handled the challenges of constructing the most modern, innovative new cancer hospital of the day. For that he needed legislative and university support in big doses. Working with Texas Legislators required a learning process, and for that he found someone who knew how to get things done in Austin better than the legislators themselves.

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