Milestones:Cobalt-60 Radiation Cancer Treatment Machines, 1951
- Date Dedicated
- 2025/05/27
- Dedication #
- 271
- Location
- London, ON
- Saskatoon, SK
- IEEE Regions
- 7
- IEEE sections
- London, North Saskatchewan
- Achievement date range
- 1951
Title
Cobalt-60 Radiation Cancer Treatment Machines, 1951
Citation
In 1951, two Canadian teams of medical physicists, engineers, and radiation oncologists in London, Ontario and Saskatoon, Saskatchewan independently, yet cooperatively, designed and assembled the first treatment machines that directed gamma radiation produced by radioactive cobalt-60 onto cancerous tumours in patients. First applied at Victoria Hospital, London on 27 October 1951, this revolutionary treatment has since been used to extend the lives of millions of patients around the world.
French translation:
Appareil De Traitement Du Cancer Par Rayonnement Cobalt-60, 1951
En 1951, deux équipes (à London et Saskatoon) composées de physiciens médicaux, d'ingénieurs et de radio-oncologues ont conçu indépendamment, mais en collaboration les premiers appareils de radiothérapie au cobalt-60 focalisant le rayonnement gamma directement sur les tumeurs cancéreuses. Les premiers traitements ont été effectués le 27 octobre à London et le 8 novembre à Saskatoon en 1951. Ce traitement révolutionnaire a prolongé la vie de millions de patients dans le monde.
Street address(es) and GPS coordinates of the Milestone Plaque Sites
London ON: 42.959725893147514, -81.22562213293283.
Saskatoon SK: 52.136222, -106.630443, London ON: 42.959725893147514, -81.22562213293283. Saskatoon SK: 52.136222, -106.630443
Details of the physical location of the plaque
London ON: in the garden area to the visitors’ right at the main entrance to the Cancer Program.
Saskatoon SK: on outside wall adjacent to main entrance to building.
How the plaque site is protected/secured
In both locations, the plaques will be external and available to the public on a 24-hour basis. The areas are overseen by security personal (Victoria Hospital, University of Saskatchewan) and are generally considered to have a low risk for vandalism.
Historical significance of the work
The pursuit of the “cure” for human ailments has likely been the goal of sentient beings since the Stone Age. While various herbs, potions and prayers prevailed for millennia, modern medical and technological advances within the last 200 years have accelerated at an exponential rate.[1] Modern chemistry (pharmaceuticals) has made a significant contribution to our arsenal of modern weapons against disease, but for ailments such as cancer, more tools were needed.
Röntgen’s discovery of X rays in 1895 and Becquerel’s discovery of radioactivity the next year was followed in 1898 by the isolation of radioactive isotopes suitable for medical applications by Becquerel and the Curries [1][13]. By the 1920s, the use of radiation in treatment of cancer, aka radiotherapy, was well known to be effective at killing cancerous cells, but unfortunately is equally effective at killing normal, healthy cells [2]. To be a practical and effective tool for cancer treatment, it is necessary to focus the radiation, as much as possible, on the cancerous cells. For tumors deep inside the body, it is also necessary for the radiation to penetrate sufficiently to reach its target without killing the healthy cells along its path.
Early radiotherapy had challenges with penetration, focus, intensity control, safety (for both operators and patients) and cost. It would require several subsequent serendipitous events to allow the development of radiotherapy technology that would address these early issues. Cobalt-60 and the “cobalt bomb” radiotherapy developed and first used in London and Saskatoon, Canada, were the foundation of a new era in radiotherapy technology. The development of cobalt-60 radiotherapy represented a momentous breakthrough providing much improved penetration control and reduced complications, along with much lower skin reactions, at a relatively low cost.[1][13]
Prior to the development of artificial radioisotopes, radiotherapy was largely limited to low-energy sources (kilovoltage X-ray tubes) with limited penetration capabilities. Megavoltage machines (such as betatron and Van de Graaff generator) producing megavoltage X rays have already been available during 1940s and 1950s, however, they were very sophisticated as well as costly and therefore not widely available. The significant development of cobalt-60-based treatment machines resulted in a progression from kilovoltage to megavoltage energy and was considered a giant leap forward in the practice of radiotherapy.” [1] The co-development of the “cobalt-bomb” treatment machines solved many outstanding roadblocks to a treatment option that has been credited with saving millions of lives.
The vision and dedication of the scientists involved in the development of a cobalt source led to the design and manufacture of machines that could safely hold and control the cobalt-60 source. This, combined with development of appropriate radiation dosimetry techniques, led to the first “cobalt bomb” treatments at the Victoria Hospital in London, Ontario on 27 October 1951 and at the University of Saskatchewan in Saskatoon on 8 November 1951. Thus began a new era of megavoltage radiation therapy that was cost-effective and has been benefitting millions of patients around the globe for decades [1].
Obstacles that needed to be overcome
While X-rays had been used for cancer treatment since the 1920s, the energy of kilovoltage X rays was not high enough to allow the treatment of cancerous growths deep inside the body. The radioactive isotope radium-226 was used to provide a higher energy source, but its high cost, limited penetration, and safety issues severely limited its use for widespread cancer treatments. Nuclear work in the 1930s and 1940s resulted in the capability to produce artificial nuclear isotopes, one of which was cobalt-60, with a long enough half-life and sufficiently energetic to potentially be useful as a treatment radiation source. The development of a suitable source, a machine to contain it, and a methodology and data to control it were still required before this potential could be realized in a practical setting.
Features that set this work apart from similar achievements
A comprehensive review of the chain of events that led to the introduction of cobalt-60 radiotherapy was presented by Van Dyk in 2020 [1]. The essential aspects of cobalt-60 radiotherapy are described in a Wikipedia article [2]. Professional guidance concerning external beam radiotherapy, including cobalt-60 radiotherapy, are presented in [3]-[5]. Contemporary accounts of the introduction of cobalt-60 radiotherapy include [6]-[8]. Retrospective accounts of the development of cobalt-60 radiotherapy that have appeared in various professional journals include [9]-[12]. Accounts of the 60th anniversary celebrations of the first treatment are given in [13] and [14]. In 2020, the contributions of Sylvia Fedoruk to the initial work at the University of Saskatchewan were highlighted in a biography and associated news releases [15], [16].
At the time of its development, the main “competitors” to a cobalt-60-sourced radiation tool were kilovoltage X rays and radium-226-based radiation treatment (teleradium machines). All were ineffective for treatment of deep-seated tumours, were relatively expensive and had safety concerns. As described above and in the references, effective high-energy x-ray treatment involved intimidating, massive machines to achieve the high voltages required but yet were still limited in depth of penetration and were therefore ineffective for deep-seated cancerous growths. The high voltages required to be even reasonably useful made this option expensive and the output was also inconsistent, resulting in complicated dosage control. Radium-226 radiation was also plagued by only shallow penetration limitations and radium sources were relatively expensive. Moreover, the radium-226 decaying process also resulted in a radioactive gas and associated safety concerns for operators.
Cobalt radiation treatment grew out of a collaboration and coincidence of events that addressed the limitations and shortcomings of previous cancer treatment options. Nuclear reactor developments in the 1930s and 1940s allowed the transformation of naturally-occurring cobalt-59 into a relatively long-lived isotope cobalt-60, which allowed medical physicists to envision and propose the use of artificial radioactive isotopes in cancer treatment. The capability and willingness of Chalk River scientists to develop cobalt-60 sources and the enthusiastic uptake of the opportunity by researchers and medical personnel to design and build working therapy machines resulted in practical radiation therapy being introduced to the oncological community in very short order after the necessary pieces were in place.
Significant references
References
Reviews
[1] J. Van Dyk, J. J. Battista and P. R. Almond, "A Retrospective of Cobalt-60 Radiation Therapy: "The Atom Bomb that Saves Lives"," Medical Physics International, Special Issue on the History of Medical Physics, vol. 4, pp. 327-350, 2020.
[2] "Cobalt Therapy," Wikipedia, 4 May 2020. [Online]. Available: https://en.wikipedia.org/wiki/Cobalt_therapy [Accessed 25 September 2020].
Professional Guidance
[3] E. B. Podgorsak, "Treatment Machines For External Beam Radiotherapy," in Radiation Oncology Physics: A Handbook for Teachers and Students, Vienna, International Atomic Energy Agency, ch. 5, 2005.
[4] B. R. Page et al., "Cobalt, Linac, or Other: What Is the Best Solution for Radiation Therapy in Developing Countries?," International Journal of Radiation Oncology Biology Physics, vol. 89, no. 3, pp. 476-480, 2014.
[5] L. J. Schreiner, C. P. Joshi, J. Darko, A. Kerr, G. Salomons, S. Dhanesar, "The role of Cobalt-60 in modern radiation therapy: Dose delivery and image guidance," Journal of Medical Physics, vol. 34, no. 3, (ICMP 2008 Special Issue), pp. 133-136, 2009.
Contemporary Accounts
[6] University of Saskatchewan, "cobalt60.usask.ca," University of Saskatchewan Archives, 01 January 1952. [Online]. Available: https://cobalt60.usask.ca/timeline.php#1951. [Accessed 16 June 2023].
[7] E. Hutton, "The Atom Bomb That Saves Lives," Maclean's Magazine, pp. 7-9, 49-53, 15 February 1952.
[8] L. M. Miller and J. Monahan, "Cobalt 60 - "Poor Man's Radium,"" Reader's Digest, pp. 42-46, October 1952.
Retrospective Accounts in Professional Journals
[9] M. D. Schultz, "The Supervoltage Story," The American Journal of Roentgenology, vol. 124, no. 4, pp. 541-559, 1975.
[10] C. S. Houston and S. O. Fedoruk, "Saskatchewan's role in radiotherapy research," Canadian Medical Association, vol. 132, pp. 854-864, 1 April 1985.
[11] R. F. Robison, "The race for megavoltage - X-rays versus telegamma," Acta Oncologica, vol. 34, no. 8, pp. 1055-1074, 1995.
[12] S. Gibson, "Beaming with confidence," The Ontario Technologist, pp. 16-18, Mar./Apr. 2016.
60th Anniversary Celebrations
[13] London Health Sciences Centre, "Celebrating the 60th anniversary of the world's first cancer treatment with cobalt-60," 27 October 2011. [Online]. Available: https://www.lhsc.on.ca/about-lhsc/celebrating-the-60th-anniversary-of-the-worlds-first-cancer-treatment-with-cobalt-60. [Accessed 25 September 2020].
[14] CBC News, "Cobalt bomb officially unveiled at Saskatoon museum," 4 December 2011. [Online]. Available: https://www.cbc.ca/news/canada/saskatchewan/cobalt-bomb-officially-unveiled-at-saskatoon-museum-1.1102354. [Accessed 16 June 2023].
Biography - Sylvia Fedoruk
[15] "New Biography Sheds Light on Fedoruk's Radiant Life," USask Research Profile and Impact, 11 September 2020. [Online]. Available: https://news.usask.ca/articles/people/2020/new-biography-sheds-light-on-fedoruks-radiant-life.php. [Accessed 17 July 2023].
[16] J. Shewaga, "University of Saskatchewan," 13 November 2020. [Online]. Available: https://news.usask.ca/articles/research/2020/uniquely-usask-cobalt-60-treatment-at-usask-made-medical-history.php. [Accessed 16 June 2023].
Supporting materials
Compiled by the proposers
[1] Media:A_Retrospective_of_Cobalt-60_Rediation_Therapy.pdf
[2] Media:Beaming_with_Confidence_fromOACETT.pdf
[3 ]Media:60th_anniversary_of_first_cancer_treatment_with_Cobalt-60_LHSC.pdf
[4] Media:Cobalt_therapy_Wikipedia.pdf
[5] Media:Cobalt_timeline_UofS_1951.pdf
[6] Media:canmedaj00258-0132.pdf
[7] Media:Cobalt_bomb_officially_unveiled_at_Saskatoon_museum_CBCNews.pdf
[8] Media:Fedoruk_radiant_life.pdf
[9] Media:The_Race_For_Megavoltage_X-Rays_Versus_Telegamma.pdf
[10] Media:The_Cancer_Bomb_Nov-2020_Shewaga.pdf
[11] Media:The_Atom_Bomb_That_Saves_Lives_Macleans_FEBRUARY-15-952.pdf
[13] Media:Cobalt_Linac_or_Other_What_Is_the_Best_S.pdf
[14] Media:Western_News_Battista_Cobalt-60_celebrates_60_years.pdf
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