Nearly 45 per cent of Canadians will develop cancer at some point in their lifetime and one in five will die from the disease.
Radiation therapy, which uses beams of intense energy to kill cancer cells or shrink tumours, is one of the most effective treatments. It’s been in use for more than a century and, although refined over the years, can cause significant side effects, such as fatigue, hair loss and nausea, among many others.
This is one of the reasons why a group of Carleton University researchers, led by physicists Rowan Thomson and Sangeeta Murugkar, are working on a multidisciplinary project to learn more about the impacts of radiation at a cellular level.
Their research aims to improve radiation therapy, enhance the use of radiation as a diagnostic tool and help protect people such as nuclear power plant workers and x-ray technicians from low-dose exposure.
Ultimately, their goal is to develop a novel system for evaluating radiation energy deposited in cells and the associated cascade of biological events. This will not only be preventative, minimizing side effects and the risks of exposure, but could also lead to more personalized treatment.
“About half of all cancer patients will undergo radiation therapy,” says Thomson.
“In general, we don’t have a good understanding of the effects of low doses of radiation. If we can improve our knowledge, we’ll be in a better position to plan and evolve treatments. Anything we can do to improve radiation therapy has the potential to affect many, many Canadians.”
Determining the Correct Dose
One of the more challenging aspects of radiation therapy is determining the correct dose to give to a patient. If doctors are treating breast cancer, for instance, the dose must be strong enough to target the tumour but not so intense that it burns the surrounding skin.
To calculate dosage more accurately, Carleton researchers are zooming in to micron-scale resolution and studying how individual cells respond to radiation. This requires an all-hands-on-deck approach.
First, Carleton students “culture” cells — growing them in a controlled environment — in Health Sciences researcher Edana Cassol‘s lab. Next, the cells are irradiated at the National Research Council in Ottawa’s east end and brought back to campus, where a chemical analysis technique called Raman spectroscopy is performed in Murugkar’s lab. This provides an experimental map of how cells respond to radiation, with Carleton bioinformatics researcher Sanjeena Dang analyzing the results.
This project is supported by the federal New Frontiers in Research Fund, which facilitates high-risk, high-reward collaborations, and also involves partners at Health Canada.
Murugkar, a medical physicist at Carleton, is an expert in light-matter interactions. She is focused on developing new optical tools for the rapid detection, treatment and monitoring of diseases such as cancer.
“We are building optical instruments and developing data measurement and analysis methods,” says Murugkar.
“This will tell us, at a very microscopic scale, which cells have been exposed to ionizing radiation.”
A Step Toward Personalized Treatment
Beyond further refining radiation therapy, Murugkar sees tremendous potential for a “laser spectroscopy system” as a diagnostic tool to monitor the response to radiation treatment.
It typically takes around two weeks to get biopsy results back from a lab. Even a frozen-section biopsy, which is done during an operation to help guide surgeons, can take half an hour.
But Murugkar envisions a system that uses short pulses of light to determine in “near real time whether the tissue in question is responding to radiation treatment — whether a tumour is shrinking.”
Compact, user-friendly tools like this, she says, could be deployed in a diagnostic lab or a clinical setting.
“They can really help inform decision making. That would be a huge step in the right direction.”
It could also lead toward personalized treatment.
Everybody responds to radiation differently, according to Thomson, yet current therapies are essentially one-size-fits-all. They don’t account for how sensitive to radiation an individual patient is.
But what if, she asks, a sample of cancerous tissue could be irradiated and the cellular response assessed by the type of unobtrusive technique the Carleton team is developing?
“You could look at the response to the radiation and use that information to inform the treatment,” says Thomson.
“That would really help personalize the treatment. This would be a new level of care and protection. Right now, it’s just a research scenario. But imagine if we could do this one day. That’s why this is such meaningful work.”
Lead image by Povozniuk / iStock