On Dec. 24, 1936, John Lawrence, known as the “father of nuclear medicine,” treated a a 28-year-old patient for leukemia using a radioactive isotope of phosphorus-32 produced in one of his brother’s cyclotrons. Lawrence administered a radioactive isotope of phosphate, the first time that a radioactive isotope was used in the treatment of a human disease.

His brother Ernest was Director of Physics at the University of California, Berkeley where his research centered on nuclear physics  His early work was on ionization phenomena and the measurement of ionization potentials of metal vapours. In 1929 he invented the cyclotron, a device for accelerating nuclear particles to very high velocities without the use of high voltages.

In 1939, Lawrence was awarded the Nobel Prize in Physics “for the invention and development of the cyclotron and for results obtained with it, especially with regard to artificial radioactive elements.”