Harold E. Johns
Encyclopedia
Harold Elford Johns, OC
(4 July 1915 – 23 August 1998) was a Canadian
medical physicist
, noted for his extensive contributions to the use of ionizing radiation
to treat cancer
.
. He lived in China until 1926, when political unrest there prompted his parents to return to North America
. After spending time in Tacoma, Washington
, and in Brandon, Manitoba
, his family settled in Hamilton, Ontario
.
In Hamilton, Johns pursued a degree in mathematics
and physics
at the McMaster University
, and he completed his bachelor of science
degree (B.Sc.) in 1936. He then moved to the University of Toronto
, where he earned his master of arts
and Doctor of Philosophy
(Ph.D.) degrees in physics in 1939.
. For the duration of the war, he taught physics, mathematics, radar systems
, and radio navigation
to newly recruited airplane pilots as part of the British Commonwealth Air Training Plan
. Based on his radiography
and physics experience, Johns was also involved in non-invasive X-ray
testing of metal aircraft castings. A meeting in August 1946 with William Valentine Mayneord
, while Mayneord was at the Atomic Energy Project at Chalk River, Ontario
, contributed to Johns's making a career in medical physics.
Johns married his wife, Sybil Hawkins Johns, in 1940. Their marriage lasted until Johns's death fifty-eight years later.
. It was there that he conducted his pioneering research in the use of cobalt-60
as a gamma ray
source for the radiation therapy
in cases of cancer
.
Interest in nuclear technology exploded in post-war Canada. Nuclear research facilities constructed at the Chalk River Laboratories
, 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 - the NRX
- was located at Chalk River, and it provided a source of activated cobalt-60 for Johns's experiments.
Two groups - Johns's at the University of Saskatchewan, and another one in London, Ontario
- designed and constructed external beam radiotherapy
instruments using radioactive cobalt sources. The first treatment of a patient using the new source was carried out in London, Ontario, on 27 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's original treatment device was used in Saskatchewan until 1972.
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.
Order of Canada
The Order of Canada is a Canadian national order, admission into which is, within the system of orders, decorations, and medals of Canada, the second highest honour for merit...
(4 July 1915 – 23 August 1998) was a Canadian
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
medical physicist
Medical physics
Medical physics is the application of physics to medicine. It generally concerns physics as applied to medical imaging and radiotherapy, although a medical physicist may also work in many other areas of healthcare...
, noted for his extensive contributions to the use of ionizing radiation
Ionizing radiation
Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...
to treat cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
.
Early life and education
Johns was born to missionary parents in Szechuan, ChinaChina
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. He lived in China until 1926, when political unrest there prompted his parents to return to North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. After spending time in Tacoma, Washington
Tacoma, Washington
Tacoma is a mid-sized urban port city and the county seat of Pierce County, Washington, United States. The city is on Washington's Puget Sound, southwest of Seattle, northeast of the state capital, Olympia, and northwest of Mount Rainier National Park. The population was 198,397, according to...
, and in Brandon, Manitoba
Brandon, Manitoba
Brandon is the second largest city in Manitoba, Canada, and is located in the southwestern area of the province. Brandon is the largest city in the Westman region of Manitoba. The city is located along the Assiniboine River. Spruce Woods Provincial Park and CFB Shilo are a relatively short distance...
, his family settled in Hamilton, Ontario
Hamilton, Ontario
Hamilton is a port city in the Canadian province of Ontario. Conceived by George Hamilton when he purchased the Durand farm shortly after the War of 1812, Hamilton has become the centre of a densely populated and industrialized region at the west end of Lake Ontario known as the Golden Horseshoe...
.
In Hamilton, Johns pursued a degree in mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
and physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
at the McMaster University
McMaster University
McMaster University is a public research university whose main campus is located in Hamilton, Ontario, Canada. The main campus is located on of land in the residential neighbourhood of Westdale, adjacent to Hamilton's Royal Botanical Gardens...
, and he completed his bachelor of science
Bachelor of Science
A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years .-Australia:In Australia, the BSc is a 3 year degree, offered from 1st year on...
degree (B.Sc.) in 1936. He then moved to the University of Toronto
University of Toronto
The University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...
, where he earned his master of arts
Master of Arts (postgraduate)
A Master of Arts from the Latin Magister Artium, is a type of Master's degree awarded by universities in many countries. The M.A. is usually contrasted with the M.S. or M.Sc. degrees...
and Doctor of Philosophy
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
(Ph.D.) degrees in physics in 1939.
Early career
Johns' graduation coincided with the start of World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. For the duration of the war, he taught physics, mathematics, radar systems
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
, and radio navigation
Radio navigation
Radio navigation or radionavigation is the application of radio frequencies to determine a position on the Earth. Like radiolocation, it is a type of radiodetermination.The basic principles are measurements from/to electric beacons, especially...
to newly recruited airplane pilots as part of the British Commonwealth Air Training Plan
British Commonwealth Air Training Plan
The British Commonwealth Air Training Plan , known in some countries as the Empire Air Training Scheme , was a massive, joint military aircrew training program created by the United Kingdom, Canada, Australia and New Zealand, during the Second World War...
. Based on his radiography
Radiography
Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....
and physics experience, Johns was also involved in non-invasive X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
testing of metal aircraft castings. A meeting in August 1946 with William Valentine Mayneord
William Valentine Mayneord
William Valentine Mayneord, CBE FRS was a British radiologist and pioneer in the field of medical physics.He was born in Redditch, Worcestershire to Walter and Elizabeth Mayneord but after the early death of his mother was adopted by an aunt in Evesham...
, while Mayneord was at the Atomic Energy Project at Chalk River, Ontario
Chalk River, Ontario
Chalk River is a Canadian rural community part of the Laurentian Hills municipality in Renfrew County, Ontario. It is located in the Upper Ottawa Valley along Highway 17 , 10 km inland from the Ottawa River, approximately 21 km northwest of Petawawa, and 182 km northwest of Ottawa...
, contributed to Johns's making a career in medical physics.
Johns married his wife, Sybil Hawkins Johns, in 1940. Their marriage lasted until Johns's death fifty-eight years later.
Development of cobalt-60 in medical treatment
After the close of the war, Johns was invited to work with Ertle Harrington at the University of SaskatchewanUniversity of Saskatchewan
The University of Saskatchewan is a Canadian public research university, founded in 1907, and located on the east side of the South Saskatchewan River in Saskatoon, Saskatchewan, Canada. An "Act to establish and incorporate a University for the Province of Saskatchewan" was passed by the...
. It was there that he conducted his pioneering research in the use of cobalt-60
Cobalt-60
Cobalt-60, , is a synthetic radioactive isotope of cobalt. Due to its half-life of 5.27 years, is not found in nature. It is produced artificially by neutron activation of . decays by beta decay to the stable isotope nickel-60...
as a gamma ray
Gamma ray
Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency . Gamma rays are usually naturally produced on Earth by decay of high energy states in atomic nuclei...
source for the radiation therapy
Radiation therapy
Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
in cases of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
.
Interest in nuclear technology exploded in post-war Canada. Nuclear research facilities constructed at the Chalk River Laboratories
Chalk River Laboratories
The Chalk River Laboratories is a Canadian nuclear research facility located near Chalk River, about north-west of Ottawa in the province of Ontario.CRL is a site of major research and development to support and advance nuclear technology, in particular CANDU reactor...
, Chalk River, Ontario
Chalk River, Ontario
Chalk River is a Canadian rural community part of the Laurentian Hills municipality in Renfrew County, Ontario. It is located in the Upper Ottawa Valley along Highway 17 , 10 km inland from the Ottawa River, approximately 21 km northwest of Petawawa, and 182 km northwest of Ottawa...
near the end of the war were expanded and opened to civilian research projects. The first operational nuclear reactor outside the United States - the NRX
NRX
NRX was a heavy water moderated, light water cooled, nuclear research reactor at the Canadian Chalk River Laboratories, which came into operation in 1947 at a design power rating of 10 MW , increasing to 42 MW by 1954...
- was located at Chalk River, and it provided a source of activated cobalt-60 for Johns's experiments.
Two groups - Johns's at the University of Saskatchewan, and another one in London, Ontario
London, Ontario
London is a city in Southwestern Ontario, Canada, situated along the Quebec City – Windsor Corridor. The city has a population of 352,395, and the metropolitan area has a population of 457,720, according to the 2006 Canadian census; the metro population in 2009 was estimated at 489,274. The city...
- designed and constructed external beam radiotherapy
External beam radiotherapy
External beam radiotherapy or teletherapy is the most common form of radiotherapy. The patient sits or lies on a couch and an external source of radiation is pointed at a particular part of the body...
instruments using radioactive cobalt sources. The first treatment of a patient using the new source was carried out in London, Ontario, on 27 October 1951.
In early 1952, Maclean's
Maclean's
Maclean's is a Canadian weekly news magazine, reporting on Canadian issues such as politics, pop culture, and current events.-History:Founded in 1905 by Toronto journalist/entrepreneur Lt.-Col. John Bayne Maclean, a 43-year-old trade magazine publisher who purchased an advertising agency's in-house...
magazine had dubbed the cobalt-source radiotherapy machine the cobalt bomb - a tongue-in-cheek tribute to this peaceful use of nuclear technology.
Johns's original treatment 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 HospitalPrincess Margaret Hospital (Toronto)
Princess Margaret Hospital is located in downtown Toronto, Ontario, Canada on University Avenue at College Street. It is part of the University Health Network...
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
Arthur Ham
Arthur Worth Ham was a prominent Canadian histologist. His textbook Histology is considered by many practitioners an indispensable reference.-Early life, education, and tennis:...
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 CanadaOrder of CanadaThe Order of Canada is a Canadian national order, admission into which is, within the system of orders, decorations, and medals of Canada, the second highest honour for merit...
(1978) - Emeritus University Professor of the University of TorontoUniversity of TorontoThe University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...
- Canadian Medical Hall of FameCanadian Medical Hall of FameThe Canadian Medical Hall of Fame is a Canadian charitable organization, founded in 1994, that honours Canadians who have contributed to the understanding of disease and improving the health of people. It has a museum in London, Ontario, and has an annual induction ceremony.-2012:*Terry Fox*John...
inductee (1998) - Member of the Canadian Science and Engineering Hall of FameCanadian Science and Engineering Hall of FameThe Canadian Science and Engineering Hall of Fame, located at the at the Canada Science and Technology Museum in Ottawa, Ontario, honours Canadians who have made outstanding contributions to society in science and engineering. It also promotes role models to encourage young Canadians to pursue...
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
- Biographical sketch from the Canadian Nuclear Society