Obituary of Lester S. Skaggs

Lester Skaggs, a pioneer in Medical Physics, grew up on a farm in Missouri. He attended a one‑room grade school and rode a horse three miles to high school. His father expected him, the oldest of three children, to take over the farm, but Skaggs opted instead for a career in science. He earned his bachelor’s degree in chemistry from the University of Missouri in 1933 with a minor in mathematics, followed by a master’s degree in physics in 1934. In 1939 he earned a Ph.D. in nuclear physics from the University of Chicago.

After a two‑year post‑doctoral fellowship, he was drafted into the war effort, working from 1941 to 1943 for the Department of Terrestrial Magnetism at the Carnegie Institute in Washington, DC, where he designed a system based on radio waves to detect proximity to an airplane and detonate anti‑aircraft shells. In 1943, Skaggs was transferred to the Los Alamos, New Mexico, headquarters of the Manhattan Project, the secret military effort led by Robert Oppenheimer to develop the atomic bomb. At Los Alamos, Skaggs was asked to adapt his anti‑ aircraft detection system into an infallible “fuse” for the first bomb. He was told the odds of the system failing should be no greater than one in a million. After witnessing, from 20 miles away, the initial test explosion at Alamogordo, Skaggs realized that the initial plan did not leave enough time for the airplane that delivered the bomb to escape safely. So Skaggs and colleagues designed a proximity‑based detonation device triggered by distance from the ground, with two back‑up systems, that allowed the plane another 30 seconds to get out of harm’s way.

After the war, he focused on the medical applications of radiation. In 1945 he began working on a project with Donald Kerst at the University of Illinois to extract the electron beam from a betatron, that Kerst had invented for physics experiments. As the work progressed, one of the physics graduate students was diagnosed with a brain tumor for which there was no effective treatment. Skaggs was part of a team of scientists who quickly developed the technology to use the electron beam to treat the student. This was all done late at night, after the staff had gone home. It was the first time high‑energy electrons were used for radiation therapy. The radiation shrank the tumor, but did not cure it.

In 1948, Skaggs joined the faculty at the University of Chicago and in 1949 was put in charge of developing the radiation therapy facilities at the Argonne Cancer Research Hospital (ACRH), funded by the Atomic Energy Commission’s “Atoms for Peace” program. When it opened in 1953, ACRH was the first hospital devoted to the use of radiation to treat cancer. At ACRH, Skaggs and colleagues designed a cobalt treatment unit, much of which they built in the University’s machine shops. Piece‑by‑piece installation of a linear accelerator, known as the Lineac, followed. This took eight years of design, engineering, construction and testing, at a cost of $450,000 but the unit, completed in 1959, attracted patients from all over the country. It provided “the greatest degree of control ever achieved over penetration and distribution of high energy rays in medical use,” according to the University’s 1960 press release. The Lineac, which consumed power equivalent to that of a town of 100,000, remained in clinical use for 34 years.

In the mid‑1950’s, Skaggs launched the first master’s degree program in medical physics in the United States. The program expanded in the 1960’s to include a Ph.D. degree in medical physics and trained many of the leaders in the field. Skaggs, who was promoted to full professor in 1956, also designed and built one of the first analog computers for calculating the radiation dose distribution in tissues for use in planning radiation therapy. Completed in 1963, the electronic components, including 26 amplifiers, filled a small room. In the 1970s, Skaggs and colleagues developed a method to produce neutrons for radiation therapy using a cyclotron. This was the first hospital‑based fast‑ neutron therapy facility in the U.S. In 1979, at age 67, after 30 years of service, Skaggs retired from the University and spent five years at the King Faisal Specialist Hospital and Research Centre in Riyadh, Saudi Arabia, where he developed a neutron‑therapy facility and set‑up a dosimetry calibration laboratory. He returned to the U.S. in 1984. a Skaggs is survived by his three children and three grandchildren.