McMaster University

McMaster University

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Health Sciences

McMaster researchers to clarify how much radiation is safe for Canadians

Published: March 27, 2018
McMaster University: Developing a Canadian strategy on radiation safety for medical imaging

You have your X-rays taken regularly at the dentist, but you also had that X-ray of your arm after the toboggan accident and the CT scan when you had abdominal pain. You, like many Canadians, wonder how much radiation is too much.

McMaster University is now at the forefront of a campaign to develop a national strategy and action plan on radiation safety for medical imaging care in Canada.

The initiative, Canada Safe Imaging, is focused on patient radiation safety. David Koff is a founding member and chair of the campaign and its epicentre is the Medical Imaging Informatics Research Centre at McMaster. The McMaster professor is chair of the Department of Radiology for the Michael G. DeGroote School of Medicine.

"Canada Safe Imaging is part of an international movement to promote radiation safety in medicine," said Koff, who is also director of the Centre.

The impetus for the formation of Canada Safe Imaging was the Bonn Call for Action. The white paper came out of a conference co-sponsored by the World Health Organization in Bonn, Germany in December 2012. The document highlights 10 main actions and related sub-actions identified as being essential for strengthening radiation protection in medicine over the next decade.

"I took a look at what was happening nationally, and while there were numerous provincial and national organizations that had something to do with radiation, there was not a concentrated approach," said Koff.

While health care is a provincial responsibility in Canada, the campaign stresses that a focused national strategy and unified effort is needed to ensure radiation safety in medical imaging for all Canadians.

Since its creation in November 2016, Canada Safe Imaging has evolved into a world-leader in working towards the materialization of pillars in the Bonn Call for Action.

"We've been able to catch up quickly and put Canada on the map," Koff said.  

Thanks to the research of McMaster faculty members and graduate students affiliated with the Centre, as well as participation of stakeholders across the country, a national strategy and action plan could materialize in the form of a nationally-focused white paper and conference as early as 2019.

"In Canada, we are very good at getting organized and the governance structure we have built is being praised internationally," Koff said. "The model we have adopted is one of full cooperation between all the professional organizations. From day one, we have included such groups as physicists, radiation technologists, physicians, academics and non-academics."

David Koff and Jane Castelli of the Medical Imaging Informatics Research Centre at McMaster University.
David Koff and Jane Castelli of the Medical Imaging Informatics Research Centre at McMaster University.

As medical imaging technology has evolved, so has the exposure of patients and health-care workers to ionizing radiation.

Sources of ionizing radiation in medical imaging are conventional X-rays, computed tomography (CT) and mammography, as well as molecular imaging used in nuclear medicine.

Magnetic resonance imaging (MRI) and ultrasound imaging work without ionizing radiation.

Although radiation is found naturally everywhere in the environment and is considered safe, high amounts of radiation have the potential to cause cancer. Nuclear medicine exams, CT scans and diagnostic X-rays are deemed to carry low-risk, but some members of the public have raised questions about unintended side effects.

The team behind Canada Safe Imaging has partnered with Radiation Safety Institute of Canada and Le Centre d'Expertise Clinique en Radioprotection to help expand an existing question and answer service available to health professionals and the general public.

The service, called Questions About Radiation, launched to the public in 2017. It can be accessed by calling 1-800-263-5803. The English service is available weekdays from 9 a.m. to 5 p.m. The French service has a voicemail where callers can leave their questions and a contact number. The email address is

"There's a lot of anxiety among the public around medical radiation," said Koff. "This allows people to call toll-free or send an email, in both official languages, if they have a question or are anxious about medical radiation exposure and receive a factual and informed response."

Jane Castelli, project manager at the Medical Imaging Informatics Research Centre at McMaster, said the resource highlights a larger misunderstanding among Canadians about the sources of medical radiation.

"There's confusion around which modalities use radiation, which also causes people unnecessary worry," she says. "For example, many people think ultrasounds are sources of medical radiation, which is not the case."

Koff said the question-and-answer service has garnered the attention of the international community.

"We are the first campaign in the world to offer a toll-free resource to answer questions from the public on radiation safety from medical care," Koff said. "It is something that had created a buzz internationally. In fact, Canada Safe Imaging is better known outside of Canada than here in our country."

Koff and other members of Canada Safe Imaging are also working with other campaigns under the International Society of Radiology to create a universal document of frequently answered questions for usage by both the general public and health professionals.

Also aligned with the Bonn recommendations to promote research in radiation protection in medicine, Koff is working on a number of related projects. One such initiative is an extensive data review of current medical radiation thresholds.  

"There is always a risk-benefit," he says. "Health professionals and patients should have as much information as possible to determine the risk of the X-ray or CT versus the benefit of a possible diagnosis."

"We see the role of Canada Safe Imaging to protect radiation medical care against abuse."

The Medical Imaging Informatics Research Centre at McMaster is hosting its annual Medical Imaging Informatics and Teleradiology Conference on Friday, May 4, 2018 at Liuna Station in Hamilton. This year's theme is Connecting Imaging and Information in the Era of AI. For more information or to register, visit

For more information on Canada Safe Imaging, visit

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