A woman in physics: Exploring science to find your way

Marilyn Tremblay, head of the National Calibration Reference Centre for Bioassay and In Vivo Monitoring at Health Canada’s Human Monitoring Laboratory, became interested in science in CEGEP when she enrolled in the Physical Technology Technician program, specializing in photonics. “I’ve always loved the manual part of science, but I also wanted to understand the theory,” explained Marilyn. “I immediately got the hang of it.”

Originally from Quebec City, Marilyn saw many opportunities in photonics, the science of light, since she was right in the centre of Cité de l’Optique. Following an interlude in Calgary, Alberta, she was admitted to the University of Quebec at Trois-Rivières in physics to further diversify her knowledge.

“During the last summer of my studies, I worked for Calian, a company offering professional services in the fields of health, IT, training, engineering and manufacturing, at the Kingston Military Electronics School,” said Marilyn. “I stayed there for five years to teach the Performance-Based Electronics training course while completing my bachelor’s degree by correspondence.” During this time, she had the chance to work with a SLOWPOKE, a small nuclear reactor for university research, which encouraged her to pursue a master’s degree in power and nuclear engineering at École Polytechnique de Montréal.

While Marilyn was completing her master’s degree, she had the opportunity to work on a research project with Health Canada’s Nuclear Emergency Preparedness and Response Division. She was at the right place at the right time, because the Fukishima Daiichi accident occurred while she was there and she remained with Health Canada in the Radiation Health Assessment Division.

Her curiosity led her to perform internal dosimetry, which involves obtaining the dose caused by the accidental ingestion or inhalation of radioactive products. “Nuclear workers can use solid or liquid radioactive products, so they have to follow very strict procedures,” explained Marilyn.

The Human Monitoring Laboratory is responsible for ensuring that internal dosimetry services in Canada meet the technical and quality assurance requirements dictated by the Canadian Nuclear Safety Commission. To do this, Marilyn’s team sends samples to test the capacity of these laboratories, which are located in Canadian nuclear power plants, hospitals, etc., to ensure that workers are well protected.

“It’s not routine work. We do things such as measuring the inside of the human body, computer modelling and 3D printing of anthropomorphic phantoms,” said Marilyn. “I really like trying new things to see where they will take me.”

The laboratory also includes two counting chambers with sophisticated detectors that can identify extremely small amounts of radioactive materials found in the human body. Although actual cases are rare, measurements are sometimes obtained from some members of the public. For example, Marilyn recounts the case of a man who was purifying radium in the 1940s. We don’t know exactly what happened, but he accidentally ingested some radium. Since then, he has been to the lab a few times to measure the amount of radium in his bones.

It is possible to determine the material and the amount ingested or inhaled by workers by taking dosimetry measurements. This internal dose is added to the workers’ external exposure to provide a true picture of the situation. If the doses are too high, the Canadian Nuclear Safety Commission determines the recommendations and the procedures for workers to follow.

“There aren’t many women in my field. In fact, I’m the only one in my lab,” said Marilyn. “I find it interesting because men and women don’t have the same approaches; we don’t think the same way. We complement each other well.”

“I encourage girls to go into science and try all kinds of different things. Exploring is how you find out what you’re interested in. It’s hard to know until you try!” said Marilyn enthusiastically.


Let’s draw attention to the incredible work of women in science! This article is part of a month-long series celebrating women in science, from International Day of Women and Girls in Science (February 11) to International Women’s Day (March 8). For even more articles about amazing women working in science, head over to the Canadian STEM Femmes blog.


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