Former U of S "Cobalt-60" physicist inducted into Canadian Science and Engineering Hall of Fame

Posted December 01, 2000


FOR IMMEDIATE RELEASE ? December 1, 2000

Former University of Saskatchewan medical physicist Harold Johns (1915-1998)
was posthumously inducted into the Canadian Science and Engineering Hall of
Fame Thursday at the Canada Science and Technology Museum in Ottawa.

One of the founders of medical physics, Johns made an internationally
significant contribution to medical research that has improved treatment for
cancer and relieved the suffering of countless patients worldwide.

Johns, who worked at the U of S from 1945 to 1956, was best known for his
development of the cobalt-60 cancer therapy unit in 1951. Also known as the
?cobalt bomb,? the unit revolutionized the treatment of cancers located deep
in the body, where previous radiation therapies had proven ineffective. It
has been estimated that seven million people around the world have
benefitted from cobalt-60 therapy.

Johns also developed a table of X-ray dosage rates -- at various depths in
human tissues, for a variety of energies, and for various types of treatment
equipment -- which is still used today as the basis for X-ray dosage tables.

At the Ottawa ceremony, Peter Hackett, Vice-President of Research at the
National Research Council of Canada, presented a plaque to Johns? daughter,
Gwen Greenstock.

He noted that Johns trained in mathematics and physics, taught the practical
aspects of radar and radio navigation to air force pilots, and tested
aircraft castings with X-rays. This practical orientation in physics led him
to his life's work ? the application of radiation in cancer therapy.

In 1948, Johns and his U of S physics colleagues Leon Katz and Ertle
Harrington were instrumental in obtaining Canada's first betatron
accelerator for research into the forces at work in the atomic nucleus. This
25-million volt device facilitated research in the basic sciences of
physics, chemistry, and biology, as well as cancer treatment.

It was from this work that the U of S went on to become a centre of
accelerator expertise and is now the site of the $173.5-million Canadian
Light Source synchrotron project which is now under construction on the
campus. (For more information, see www.cls.usask.ca )

Johns established a program in medical physics that focused on X-ray
radiation and radioactive isotopes for cancer treatment. The radiation
research group worked on the problem of determining the appropriate doses of
radiation and controlling the radiation during treatment.

Johns went on to University of Toronto where he helped establish the
department of medical biophysics. He eventually becoming Chair of the
department and established a multidisciplinary graduate program stressing
both quantitative and analytical approaches to research.

The Canadian Science and Engineering Hall of Fame is a partnership of the
Canada Science and Technology Museum Corporation and the National Research
Council of Canada which seeks to promote Canadian achievements and careers
in science and engineering.

At present, there are 26 inductees. These are chosen by a selection
committee composed of distinguished Canadians who represent some of the most
prestigious scientific and engineering organizations in the country. They
identify inspiring role models for young Canadians, individuals who have had
a lasting impact on society.

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For more information, contact:

Kathryn Warden
Research Communications Officer
Office of the Vice-President Research
(306) 966-2506
kathryn.warden@usask.ca
www.usask.ca/research