Building on a legacy of nuclear medicine excellence

U of S medical physicists Harold Johns and Sylvia Fedoruk developed technology that revolutionized cancer treatment around the world.

Molly Birtch, a 43-year-old Saskatchewan woman, made history at University Hospital (now Royal University Hospital) on Nov. 8, 1951 when she was placed under a suspended steel-encased lead cylinder and received a carefully calibrated dose of cobalt-60 radiation that directly targeted her cervical cancer tumours.

A University of Saskatchewan research team had just developed what became known as the “cobalt bomb”—the high-tech piece of equipment that accurately delivered the correct dose of radiation to cure her deep-seated cancer and allowed her to live another 47 years.

This achievement marked a ground-breaking advance in global cancer treatment and positioned the U of S to become a leader in areas of nuclear medicine, biomedical imaging and related research.

The cobalt-60 beam unit, designed by U of S medical physicist Harold Johns and his team and built by machinist John MacKay at his small Acme Machine & Electric Company on Idylwyld Drive in downtown Saskatoon, was the first in the world to successfully treat a cancer patient with targeted radiation.

(A group of engineers at Eldorado Mining and Refining in London, Ont. who worked with doctors from London’s Victoria General Hospital also introduced a cobalt-60 treatment unit of a different design in 1951. While they tested their machine on a patient a few days earlier than the Saskatoon group, the patient didn’t survive.) 

Johns’ innovative machine featured a treatment cone that directed radiation to a patient’s cancer, with a “collimator” that changed the size of the beam to fit the tumour being treated.

The cobalt-60 beam therapy unit at University Hospital was used to treat more than 6,700 patients over 21 years before it was decommissioned in 1972 and replaced with a Betatron 42 unit—the first of its kind in the world.

Among the graduate students who helped Johns on the project was Sylvia Fedoruk, whose painstaking master’s thesis established the world standard for depth-dose measurements to treat tumours deep inside the body. Fedoruk went on to became the university’s first female chancellor (1986) and the province’s first lieutenant governor (1988). Today the university’s Sylvia Fedoruk Canadian Centre for Nuclear Innovation honours her contributions.

The legacy of these pioneers lives on at the U of S, which has since gone on to add the Canadian Light Source (CLS) synchrotron with biomedical beamlines and a cyclotron that is putting the university on the front lines of nuclear medicine. No other centre in Canada is better equipped to exploit the potential of molecular imaging across humans, animals, and plants.

The unique Biomedical Imaging and Therapy (BMIT) facility at the CLS is geared to life sciences research and designed to study full-size animals and humans. Researchers can use the BMIT to study, in incredible detail, soft tissue such as lungs and internal reproductive organs that are usually difficult to image. The precisely directed and extremely powerful X-rays will help to develop better cancer treatments, as well as to research ailments such as osteoarthritis and circulatory problems.

CLS scientists have also built the world’s first linear accelerator dedicated to producing the most used medical isotope, molybdenum 99, in a safe and cost-effective way without creating nuclear waste. A private spinoff company, Canadian Isotope Innovations Corp., is commercializing the product and helping to offset a global shortage of molybdenum 99 caused by the impending shutdown of aging nuclear reactors that use uranium to produce it.

Meanwhile, the new cyclotron at the university’s Saskatchewan Centre for Cyclotron Sciences (SCCS), operated by the Fedoruk Centre, is producing flurorine-18 radioisotopes—the active ingredient in the imaging agent used in PET scans performed on patients at Royal University Hospital. In addition to direct use on patients, the radioisotopes are assisting with groundbreaking research in animal, human and plant health.

Price, now a U of S Canada Research Chair, came to the U of S from New York’s Memorial Sloan Kettering Cancer Centre research hospital because SCCS’s radiochemistry labs can help his research into developing a new generation of medical imaging technology and “smart” drugs that can selectively target cancer cells.

Dadachova relocated after 16 years as a researcher at New York’s Albert Einstein College because of the concentration of facilities at the U of S that includes a research hospital, veterinary hospital and the CLS, along with ready access to an isotope-producing cyclotron.

She wants to further the work she’s done on a new radioimmunotherapy to treat patients with metastatic melanoma, and is also researching how injections of radioactive drugs can target hard-to-combat pathogens such as bacteria that are immune to many antibiotics.

More than 70 years after medical physicist Harold Johns and Saskatchewan Cancer Services director Alan Blair dropped in on premier Tommy Douglas unannounced to seek and receive authorization to buy a betatron—an event that marked another chapter in the university’s foray into nuclear medicine—U of S scientists continue to be innovators in this critically important field.

Sarath Peiris is a communications contributor to the U of S Research Profile and Impact unit.

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