Cancer Centre News

April 2009 - New Linear Accelerator Becomes Operational

The linear accelerator at WVCC with have IMRT capabilities. It is the only unit with this capability in Canada, and one of only a few veterinary units with this ability in all of North America. IMRT works by linking a 3 dimensional radiation planning workstation to a collimator that is computer controlled. Rather than just moving in an x-y direction, an IMRT collimator has multiple leaves that can move independently of each other - called a dynamic multileaf collimator (dMLC). This type of collimator allows the computer and linear accelerator to create highly complex shapes that conform to the tumor outline, while sparing normal tissue.

Additionally, the dMLC constantly moves during dose delivery, allowing small segments of a field to receive relatively more (or less) radiation. This allows very fine control of the dose delivered to normal tissue, while maximizing the dose delivered to the tumor. These small changes in field shape decrease the intensity of the radiation beam (hence the term intensity modulated) - allowing different areas within the treatment field to receive the different doses of radiation.