Confronting the high costs of calibration
It’s the ultimate recycling project: medical equipment no longer needed by Canadian clinics is being acquired by developing countries. But in the case of one device — the linear accelerator (LINAC), used to focus high-energy radiation during cancer treatments — its high price tag means those countries can’t always afford an important companion device: the calibration tool that ensures radiation doses are as accurate as possible.
Each calibration tool costs between $30,000 and 60,000 USD, so Allan Michaud, machinist technician with the Tom Baker Cancer Centre (and former SAIT instructor), challenged four students in the Design and Analysis major of the Mechanical Engineering Technology (MET) program to develop a more affordable calibration device as their capstone project.
Furthermore, he issued specific requirements: the calibration tool had to use affordable and accessible materials, be easily shipped to survive the journey to a developing country, and be 100 per cent mechanical to avoid expensive software upgrades.
The four students have created a prototype with real potential: the anywhere calibration tool (ACT).
Edward Pranoto (MET ‘15), who formed the ACT team along with fellow students Maria Tejada (MET ‘15), Rory Leung (MET ‘15), and Pheap Meas (MET ‘15), says developing the prototype involved many decisions.
For instance, while the team immediately gravitated towards the flexibility and affordability of plastic as their main material, they tried out a few kinds (including acrylic) before settling on delrin for its water and wear resistance. And while they originally planned to stick to one material, they found that some parts of the device needed to be stiffer to avoid bending out of shape and causing inconsistencies in the calibration.
“We wanted plastic but plastic is not really strong enough, so we added stainless steel and aluminum,” explains Pranoto.
The group also made design choices to accommodate not only the most common LINACs but also older models. And, because their prototype is designed to be suspended in water, the team created a form that would fit into any size container. Finally, they chose the most common size screws for the prototype’s assembly and ensured that the whole machine could fit into a 5x5x7-inch box for easy international shipping.
Pranoto, who was already familiar with the Tom Baker Cancer Centre from working there the previous summer, says he found the capstone project to be very valuable. “I really like it. It trains you to be working in an industry where you deal with clients, and people who have a higher rank. Then you also have to be able to work as a teammate,” he says.
Michaud says the prototype not only provided real-world experience for the students, but created something that might not otherwise exist. “As far as I know, no one is trying to develop a solution (for the high cost of the LINAC calibration tool) because there’s no money to be made in it. But there is still that need, and what the team has come up with is a really effective, adaptable and cheap way to accomplish it.”
Written by Suzanne Bowness