- Harold E. Johns
Harold Elford Johns (
4 July 1915 –23 August 1998 ) was a Canadian medical physicist, noted for his extensive contributions to the use ofionizing radiation to treatcancer .Early life and education
Johns was born to missionary parents in
Szechuan , China. He lived in China until 1926, when political unrest prompted his parents to return to North America. After spending time inTacoma, Washington andBrandon, Manitoba , his family settled inHamilton, Ontario .In Hamilton, Johns pursued a degree in mathematics in physics at
McMaster University and completed his B.Sc. in 1936. He then moved to theUniversity of Toronto , where he earned an M.A. and Ph.D. in physics in 1939.Early career
Johns' graduation coincided with the start of
World War II . For the duration of the war, he taught physics, mathematics, radar, and radio navigation to newly recruited pilots as part of theBritish Commonwealth Air Training Plan . Based on his radiography and physics experience, Johns was also involved in noninvasive x-ray testing of metal aircraft castings.He married his wife, Sybil Hawkins, in 1940. Their marriage lasted until Johns' death fifty-eight years later.
Cobalt bomb
After the close of the war, Johns was invited to work with
Ertle Harrington at theUniversity of Saskatchewan . It was there in Saskatoon that he conducted his pioneering research in the use of cobalt-60 as agamma ray source for the radiation treatment ofcancer .Interest in nuclear technology exploded in postwar Canada. Nuclear research facilities constructed at Chalk River, Ontario near the end of the war were expanded and opened to civilian research projects. The first operational nuclear reactor outside the United States–
NRX –was located at Chalk River, and it provided a source of activated cobalt-60 for Johns' experiments.Two groups–Johns' at the University of Saskatchewan, and another in
London, Ontario –designed and constructedexternal beam radiotherapy instruments using cobalt sources. Ultimately, the first treatment was delivered in London, on27 October 1951 .In early 1952, "
Maclean's " magazine had dubbed the cobalt-source radiotherapy machine the "cobalt bomb"—a tongue-in-cheek tribute to this peaceful use of nuclear technology.Johns' original device was used in Saskatchewan until 1972.
Ontario Cancer Institute
In 1956, Johns assumed the headship of the physics division of the Ontario Cancer Institute at Princess Margaret Hospital in Toronto.
To further scientific and medical collaborations between radiologists, radiotherapists, physicians, and physicists, Johns guided the creation of the Graduate Department in Medical Biophysics at the University of Toronto in 1958. Johns served as the second Chair of the Department, succeeding
Arthur Ham in 1960.Over the course of his career, Johns supervised sixty-eight graduate students and published more than two hundred peer-reviewed papers.
Awards
*Officer of the
Order of Canada (1978)
*Emeritus University Professor of theUniversity of Toronto
*Canadian Medical Hall of Fame inductee (1998)Further reading
*Greenstock, Clive L. A New Kind of Ray: The Radiological Sciences in Canada 1895-1995. eds. J.A. Aldrich and B.C. Lentle, The Canadian Association of Radiologists, Montreal 1995.
*Johns, Harold E. and Cunningham, John R. The Physics of Radiology, 4th Edition, Charles C Thomas, Springfield 1983.
*Johns, H.E., Bates L.M., Epp E.R., "et al." 1,000-curie cobalt 60 units for radiation therapy. "Nature". 168(4285):1035-6, 1951.
External links
* [http://www.cns-snc.ca/history/pioneers/harold_johns/hejohns.html Biographical sketch] from the Canadian Nuclear Society
Wikimedia Foundation. 2010.