Cobalt Therapy - History

History

In 1949, Dr. Harold E. Johns of the University of Saskatchewan sent a request to the National Research Council (NRC) asking them to produce Cobalt-60 isotopes for use in a cobalt therapy unit prototype. Two Cobalt-60 apparatuses were then built, one in Saskatoon in the cancer wing of the University of Saskatchewan and the other in London, Ontario. Dr. Johns collected depth-dose data at the University of Saskatchewan which would later become the world standard. The first patient to be treated with Cobalt-60 radiation was treated on October 27, 1951 at Victoria Hospital in London, Ontario. In 1961 cobalt therapy was expected to replace X-ray radiotherapy. The role of the cobalt unit has partly been replaced by the linear accelerator, which can generate higher energy radiation. Cobalt treatment still has a useful role to play in certain applications and is still in widespread use worldwide, since the machinery is relatively reliable and simple to maintain compared to the modern linear accelerator.