Skip to main content
Ingenium Logo

You are leaving IngeniumCanada.org

✖


This link leads to an external website that Ingenium does not control. Please read the third-party’s privacy policies before entering personal information or conducting a transaction on their site.

Have questions? Review our Privacy Statement

Vous quittez IngeniumCanada.org

✖


Ce lien mène à un site Web externe qu'Ingenium ne contrôle pas. Veuillez lire les politiques de confidentialité des tiers avant de partager des renseignements personnels ou d'effectuer une transaction sur leur site.

Questions? Consultez notre Énoncé de confidentialité

Ingenium The Channel

Langue

  • Français
Search Toggle

Menu des liens rapides

  • Ingenium Locations
  • Shop
  • Donate
  • Join
Menu

Main Navigation

  • Browse
    • Categories
    • Media Types
    • Boards
    • Featured Stories
  • About
    • About The Channel
    • Content Partners

Harold Elford Johns, 1915–1998

This article was originally written and submitted as part of a Canada 150 Project, the Innovation Storybook, to crowdsource stories of Canadian innovation with partners across Canada. The content has since been migrated to Ingenium’s Channel, a digital hub featuring curated content related to science, technology and innovation.

Share
Sep 9, 2016
Categories
Medicine
Categories
Sciences
Media
Article
Profile picture for user Ingenium
By: Ingenium – Canada's Museums of Science and Innovation
Dr Harold Elford Johns, inventor of the first cobalt-60 radiotherapy unit in the world. Source: University of Saskatchewan
Dr Harold Elford Johns, inventor of the first cobalt-60 radiotherapy unit in the world. Source: University of Saskatchewan

Harold Johns developed powerful new radiation instruments to treat cancer — finding peacetime uses for wartime nuclear technology.

Harold Elford Johns introduced high-energy radioactive isotopes into cancer treatment, helping to pioneer the field of nuclear medicine. Previous radiation treatments had proven ineffective, leaving cancer patients with burns and other medical complications. Johns, who joined the University of Saskatchewan’s physics department — and the province’s new Cancer Commission—in 1944, realized the high-energy x-rays could kill deeply buried cancerous cells. Working with graduate students and colleagues such as Sylvia Fedoruk, Johns proposed using a radioactive isotope called cobalt-60, which emitted powerful gamma rays. Johns worked with Saskatoon machinist John MacKay to produce a prototype machine that used cobalt-60 from Atomic Energy of Canada Limited’s NRX reactor in Chalk River, Ontario. In November 1951, the machine treated its first cancer patient in Saskatoon. Another medical research group based in London, Ontario, developed a similar machine that treated cancer patients the same year. Johns also contributed to the development of CT scanners, mammographic imaging, and to research on the effects of ultraviolet rays on DNA.

Johns was born in China, where his parents worked as missionaries. After completing work on cobalt-60 therapy, he moved to Toronto in 1956 to head the Physics Division at the Ontario Cancer Institute. He also joined the University of Toronto and was instrumental in creating the school’s medical biophysics program.

T. A. Watson, John MacKay, and Dr Harold Johns examine the original treatment cone on the cobalt-60 unit at the University of Saskatchewan. Source: University of Saskatchewan, University Archives and Special Collections, Harold Johns Collection, box 4

Drawing of the treatment cone on the cobalt-60 radiotherapy unit, by Dr Harold Johns. Source: University of Saskatchewan, Fedoruk Centre

Dr Harold Johns speaks at a conference. Source: University of Saskatchewan, University Archives and Special Collections, Harold Johns Collection, box 4

Dr Harold Johns demonstrates the operation of a cobalt-60 therapy unit to Princess Margaret and Lord Snowdon during the opening of the new wing of the Princess Margaret Hospital in Toronto, Ontario, in 1967. Source: Courtesy David Milne

Tags
Innovation Storybook
Author(s)
Profile picture for user Ingenium
Ingenium – Canada's Museums of Science and Innovation
Follow

Ingenium represents a collaborative space where the past meets the future in a celebration of creativity, discovery, and human ingenuity.

Telling the stories of people who think differently and test the limits, Ingenium honours people and communities who have shaped history — and inspire the next generation.

https://ingeniumcanada.org/about-ingenium

More Stories by

Profile picture for user Ingenium
Ingenium – Canada's Museums of Science and Innovation
The exterior of a very large rectangular building; the word “Ingenium” is visible on the front of the façade.

Case study: A second RHFAC Gold for Ingenium

The Canadian flag, set against the backdrop of a clear, blue lake and mountains in Banff National Park, Alberta.

Oh Canada! Let’s celebrate Canada Day together

“McIntosh Red” apple watercolour by Faith Fyles for the Central Experimental Farm, Ottawa, Ontario, 1920s. Source: Ingenium 1987.2334

McIntosh Red Apple

Cover of Canadian Aviation magazine featuring the first Canadian-made Hawker Hurricane, February 1940. Source: Ingenium

Hawker Hurricane

Propeller model used by W. Rupert Turnbull in 1923. Source: Ingenium 1967.1152

Variable Pitch Propeller

First flight of the Silver Dart immortalized in a painting by Robert W. Bradford , 1965 Source: Ingenium 1967.0893

Silver Dart

Boys sitting on top of telephone booths, ca.1950. Toronto, Ontario.

Hand Telephone

Related Stories

A map of the cranberry bog of Les Producteurs de Québec Limitée of Lemieux, Québec. Luc Bureau, “Un exemple d’adaptation de l’agriculture à des conditions écologiques en apparence hostiles: L’Atocatière de Lemieux,” Cahiers de géographie du Québec, December 1970, 389.

“A sea serpent without affidavit, is like roast turkey without cranberry sauce;” Or, how the Larocque family created the first cranberry bog in Québec, part 3

A large impact crater viewed from the rim, a woodern spoon full of small yellow grains, a close up of a forearm being tattooed.

3 things you should know about the untapped potential of millet, the permanence of tattoos, and asteroid airbursts

The 3.75- / 3.5-inch flight impact simulator of the National Research Council of Canada at some point during its long career, Uplands / Ottawa, Ontario. NRC.

A great Canadian success story you should know about: A brief look at the National Research Council of Canada flight impact simulators donated to the Canada Aviation and Space Museum, Part 2

Three images side by side: A little girl smells a sunflower, the DART spacecraft’s impact into the asteroid Dimorphos, and a candy apple

3 things you should know about how the DART spacecraft changed the orbit of an asteroid, how we have more than five senses, and how the science of caramel can make you a better cook!

Three images side by side, plastic-wrapped cucumbers, a woman with an inflamed shoulder, and the James Webb Space Telescope.

3 things you should know about plastic-wrapped cucumbers, the James Webb telescope, and inflammation

A small, open box containing several small metal puncturing tools, used to administer smallpox vaccine by scratching the skin and rubbing the vaccine into the scratch.

The History of Vaccines – Smallpox to COVID-19

Stethoscopes displayed in the permanent Medical Sensations exhibition at the Canada Science and Technology Museum.

Curating sound culture: Exploring the history of the stethoscope

A close-up view of a radio pill a few moments before the first volunteer patient swallowed it. Anon., “Science – Radio Made to Swallow.” Life, 29 April 1957, 74.

Take one of these pills and your innards will call me in the morning: The digestive saga of… the radio pill

A text-based advertisement for Speton.

McGill-Ingenium Fellowship: Part Two - A Tale of Two Nations: Birth Control in India and Canada (1930–60s)

Autumn vista of a river winding between pine trees and snow-capped mountains.

AI-Generated sound therapy for critically ill patients

Aticle from an issue of Guna Sundari in 1936.

McGill-Ingenium Fellowship: Part One - A Historian & Her Archives

A spliced, three-part image depicts sugar beets and a pile of white sugar and sugar cubes, a view of a partially cloud-covered ocean taken from above the Earth, and a humanoid toy robot wearing a stethoscope.

3 things you should know about beets, satellites, and robotic surgery

Footer

About The Channel

The Channel

Contact Us

Ingenium
P.O. Box 9724, Station T
Ottawa ON K1G 5A3
Canada

613-991-3044
1-866-442-4416
contact@IngeniumCanada.org
  • Facebook
  • Instagram
  • Twitter
  • Channel

    • Channel Home
    • About the Channel
    • Content Partners
  • Visit

    • Online Resources for Science at Home
    • Canada Agriculture and Food Museum
    • Canada Aviation and Space Museum
    • Canada Science and Technology Museum
    • Ingenium Centre
  • Ingenium

    • Ingenium Home
    • About Ingenium
    • The Foundation
  • For Media

    • Newsroom
    • Awards

Connect with us

Subscribe to our newsletter to receive the latest Ingenium news straight to your inbox!

Sign Up

Legal Bits

Ingenium Privacy Statement

© 2023 Ingenium

Symbol of the Government of Canada
  • Browse
    • Categories
    • Media Types
    • Boards
    • Featured Stories
  • About
    • About The Channel
    • Content Partners