1895—Wilhelm Conrad Röntgen (Röentgen)
discovers X-rays.

1896—Antoine Henri Becquerel discovers natural radioactivity.

1898—Marie and Pierre Curie isolate radium, now used to treat cancer.

1920—Ernest Rutherford suggests the possible existence
of a neutron.

1922—Niels Bohr wins the Nobel Prize for his work
defining the structure of atoms.

1931—The first cyclotron is built at the University of
California, Berkeley by physicist Ernest Lawrence.

1935—Ernest Lawrence persuades his brother, John Lawrence,
to come to Berkeley and apply physics to treat cancer.

Irène Joliot–Curie, Marie Curie's daughter, and her husband, Frédéric Joliot,
win the Nobel prize for their discovery of artificial radioactivity.

1946—Dr. Robert Rathbun Wilson proposes the use of proton
radiation therapy as a cancer treatment.

1950s—Protons are used to treat cancer at the
University of California, Berkeley, and Uppsala in Sweden.

1957—Protons are used for cancer treatments in Europe.

1961—Dr. Robert Rathbun Wilson is hired as an associate professor at
Harvard and designs a new cyclotron for Harvard University. He writes
a fundamental paper about proton therapy and the cyclotron.

Protons are used at the Harvard Cyclotron Laboratory to treat
cancer patients. 9,111 patients are treated with proton therapy
before the laboratory closes in 2002.

1960s—Dr. Luis Rosen redesigns the X–ray therapy machine to increase
the quality of X-ray beams.

1980s—Advancements are made in computer–assisted
treatment systems and imaging technologies, such as
CT imaging, MRIs, and PET scans.

1990—Medicare approves coverage for proton therapy.

1990—The first hospital–based proton treatment
facility opens in Loma Linda, CA.

1993—Indiana University Cyclotron Facility (IUCF) treats
its first patient in a research study.

1996—Midwest Proton Radiotherapy Institute (MPRI) is established.

2001—Massachusetts General opens its Northeast Proton Therapy
Center (later renamed Francis H. Burr Proton Therapy Center) in
Boston, MA.

2004—Treatments begin at MPRI.

2006–Present—Researchers are working to develop
better technology to increase the uses for proton therapy.