Harold Elford Johns (4 July 1915 – 23 August 1998) was a
Canadian
Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...
medical physicist A medical physicist is a health professional with specialist education and training in the concepts and techniques of applying physics in medicine and competent to practice independently in one or more of the subfields (specialties) of medical phys ...
, noted for his extensive contributions to the use of
ionizing radiation to treat
cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
.
Early life and education
Johns was born to missionary parents in
Szechuan,
China. He lived in China until 1926, when political unrest there prompted his parents to return to North America. After spending time in
Tacoma, Washington
Tacoma ( ) is the county seat of Pierce County, Washington, United States. A port city, it is situated along Washington's Puget Sound, southwest of Seattle, northeast of the state capital, Olympia, and northwest of Mount Rainier National Pa ...
, and in
Brandon, Manitoba, his family settled in
Hamilton, Ontario
Hamilton is a port city in the Canadian Provinces and territories of Canada, province of Ontario. Hamilton has a Canada 2016 Census, population of 569,353, and its Census Metropolitan Area, census metropolitan area, which includes Burlington, ...
.
In Hamilton, Johns pursued a degree in
mathematics and
physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
at
McMaster University
McMaster University (McMaster or Mac) is a public research university in Hamilton, Ontario, Canada. The main McMaster campus is on of land near the residential neighbourhoods of Ainslie Wood and Westdale, adjacent to the Royal Botanical Ga ...
, and he completed his
Bachelor of Science
A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years.
The first university to admit a student to the degree of Bachelor of Science was the University o ...
degree (BSc) in 1936. He then moved to the
University of Toronto
The University of Toronto (UToronto or U of T) is a public university, public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park (Toronto), Queen's Park. It was founded by royal charter in 1827 ...
, where he earned his
Master of Arts
A Master of Arts ( la, Magister Artium or ''Artium Magister''; abbreviated MA, M.A., AM, or A.M.) is the holder of a master's degree awarded by universities in many countries. The degree is usually contrasted with that of Master of Science. Th ...
and
Doctor of Philosophy
A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is ...
(PhD) degrees in physics in 1939.
Early career
Johns' graduation coincided with the start of
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
. For the duration of the war, he taught physics, mathematics,
radar systems, and
radio navigation
Radio navigation or radionavigation is the application of radio frequencies to determine a position of an object on the Earth, either the vessel or an obstruction. Like radiolocation, it is a type of radiodetermination.
The basic principles a ...
to newly recruited airplane pilots as part of the
British Commonwealth Air Training Plan. Based on his
radiography
Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography ("diagnostic" and "therapeu ...
and physics experience, Johns was also involved in non-invasive
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
testing of metal aircraft castings. A meeting in August 1946 with
William Valentine Mayneord
William Valentine Mayneord, CBE FRS (14 February 1902 – 10 August 1988) was a British physicist and pioneer in the field of medical physics.
Early life and education
He was born in Redditch, Worcestershire to Walter and Elizabeth Mayneord b ...
, while Mayneord was at the Atomic Energy Project at
Chalk River, Ontario
Chalk River (2016 population: 1029) is a small rural village, part of the Laurentian Hills municipality in Renfrew County, Ontario, Canada. It is located in the Upper Ottawa Valley along Highway 17 (Trans-Canada Highway), inland (west) from ...
, contributed to Johns's making a career in medical physics.
Johns married Sybil Hawkins Johns in 1940. Their marriage lasted until Johns's death 58 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 Saskatchewan
A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, ...
. It was there that he conducted his pioneering research in the use of
cobalt-60
Cobalt-60 (60Co) is a synthetic radioactive isotope of cobalt with a half-life of 5.2713 years. It is produced artificially in nuclear reactors. Deliberate industrial production depends on neutron activation of bulk samples of the monoisot ...
as a
gamma ray
A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...
source for the
radiation therapy
Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radi ...
in cases of
cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
.
Interest in nuclear technology burgeoned in post-war Canada. Nuclear research facilities constructed at the
Chalk River Laboratories
Chalk River Laboratories (french: Laboratoires de Chalk River; also known as CRL, Chalk River Labs and formerly Chalk River Nuclear Laboratories, CRNL) is a Canadian nuclear research facility in Deep River, about north-west of Ottawa.
CRL is ...
,
Chalk River, Ontario
Chalk River (2016 population: 1029) is a small rural village, part of the Laurentian Hills municipality in Renfrew County, Ontario, Canada. It is located in the Upper Ottawa Valley along Highway 17 (Trans-Canada Highway), inland (west) from ...
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
London (pronounced ) is a city in southwestern Ontario, Canada, along the Quebec City–Windsor Corridor. The city had a population of 422,324 according to the 2021 Canadian census. London is at the confluence of the Thames River, approximate ...
- designed and constructed
external beam radiotherapy
External beam radiotherapy (EBRT) is the most common form of radiotherapy (radiation therapy). The patient sits or lies on a couch and an external source of ionizing radiation is pointed at a particular part of the body. In contrast to brachyt ...
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 November 1951, the first Saskatoon patient, a 43-year-old mother of four, was treated for cervical cancer with a carefully calibrated dose of cobalt-60 radiation.
In early 1952, ''
Maclean's
''Maclean's'', founded in 1905, is a Canadian news magazine reporting on Canadian issues such as politics, pop culture, and current events. Its founder, publisher John Bayne Maclean, established the magazine to provide a uniquely Canadian persp ...
'' 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 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 68 graduate students, published more than 200 peer-reviewed papers, and with
John R. Cunningham, published the textbook "The Physics of Radiology".
Awards
*
Henry Marshall Tory Medal
The Henry Marshall Tory Medal is an award of the Royal Society of Canada "for outstanding research in a branch of astronomy, chemistry, mathematics, physics, or an allied science". It is named in honour of Henry Marshall Tory and is awarded bi-ann ...
(1971)
*Officer of the
Order of Canada
The Order of Canada (french: Ordre du Canada; abbreviated as OC) is a Canadian state order and the second-highest honour for merit in the system of orders, decorations, and medals of Canada, after the Order of Merit.
To coincide with the cen ...
(1978)
*Emeritus University Professor of the
University of Toronto
The University of Toronto (UToronto or U of T) is a public university, public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park (Toronto), Queen's Park. It was founded by royal charter in 1827 ...
*
Canadian Medical Hall of Fame inductee (1998)
*Member of the
Canadian Science and Engineering Hall of Fame[The Canadian Science and Engineering Hall of Fame: The Hall](_blank)
, Canada Science and Technology Museum.
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.
References
External links
from the Canadian Nuclear Society
{{DEFAULTSORT:Johns, Harold
1915 births
1998 deaths
Canadian medical researchers
Canadian physicists
Physicists from Sichuan
Officers of the Order of Canada
University of Saskatchewan faculty
University of Toronto faculty
University of Toronto alumni
McMaster University alumni
Medical physicists
Presidents of the Canadian Association of Physicists