A Brief History of Proton Therapy

Proton therapy is the most technologically advanced method to deliver radiation treatment to cancerous tumors available today.

The study of protons can be dated back to the early 1900s. Research conducted by a man named Ernest Rutherford resulted in a nuclear reaction that led to the first ‘splitting’ of the atom, where protons were first discovered. In 1903 Sir William Bragg discovered a unique effect using proton particles known as the Bragg peak. The graph below demonstrates this pronounced peak on the Bragg curve, which plots the energy loss of proton radiation during its travel through the body. This peak energy release occurs immediately before the proton particles come to rest. The phenomenon is exploited in the treatment of cancer with proton therapy to concentrate the energy of the protons on the cancerous tumor being treated while minimizing the effect on the surrounding healthy tissue.


Sir William Henry Bragg (July 2, 1862 – March 12, 1942)


In 1930, American physicist Ernest O. Lawrence and his associates invented a particle accelerator known as the cyclotron. The cyclotron would accelerate nuclear particles to very high speeds and go on to be used for the creation of seven new elements. Ernest O. Lawrence received the Nobel Prize in physics for his contributions nine years after the cyclotron’s invention.


American physicist Ernest O. Lawrence [1901-1958], photographed in 1937, adjusting the ion source of his 60-inch cyclotron.

Robert R. Wilson, a physics professor at Harvard and designer of Harvard’s cyclotron, was the first to propose using protons to treat cancer.

Robert R. Wilson was an American physicist known for his work on the Manhattan Project during World War II. He was a member of the team that developed the atomic bomb and later headed an immense group of physicists that conceived, designed, built, and operated the Fermi National Accelerator Laboratory (Fermilab) outside of Chicago.

Although Wilson was a dedicated scientist, he was also a committed advocate of human rights and championed the peaceful use of atomic energy he helped to unleash. The Oklahoma Proton Center is an example of that peaceful use.

Robert Wilson’s contribution to proton therapy was made manifest in a paper he published in 1946. Titled “Radiological Use of Fast Protons” (Radiology 1946:47:487-91), the article established the fundamentals and techniques still used today at the Oklahoma Proton Center and proton therapy centers worldwide.


Robert Rathbun Wilson (March 4, 1914 – January 16, 2000)


Berkeley Radiation Laboratory conducted extensive studies on protons and confirmed Wilson’s predictions. In 1954 they treated the first patient with protons. Researchers began to recognize the full potential of isolating protons to treat medical conditions. Advanced understanding of particle acceleration, proton beams, and their radiation treatment application has shown improved outcomes for patients diagnosed with many forms of cancer. Wilson is said to be “the father of proton therapy” for all of his research and efforts to advance proton therapy.


Lawrence’s 60-inch cyclotron, with magnet poles 60 inches in diameter, at the University of California Lawrence Radiation Laboratory (1939) the most powerful accelerator in the world at the time.
Image of a modern-day cyclotron at the Oklahoma Proton Center used to accelerate protons to more than two-thirds the speed of light and utilized in the treatment of human cancers.

Proton therapy has treated more than 200,000 people worldwide.

It’s estimated that by the year 2030, between 300,000 and 600,000 patients will have received proton therapy treatment. A survey conducted by the National Association for Proton Therapy (NAPT) found the number of centers in the United States offering proton therapy more than doubled from 2012 to 2016. The number of patients receiving proton therapy treatment increased by 70% during this period.

Oklahoma Proton Center was one of the earliest adopters of proton therapy treatments for cancer in the state in 2009 and just the sixth proton center in the country. The center has treated thousands of patients from all over the United States and from fifteen different countries since its inception. Oklahoma Proton Centers doctors have experience treating patients with a wide variety of conditions, including breast cancer, brain & central nervous system cancer, lung cancer, prostate cancer, head and neck cancer, liver cancer, esophageal cancer, and many other diagnoses. The facility features four treatment rooms with advanced in-room imaging capabilities.