Your focus may be centered on radiation therapy, but having a broader knowledge of the machines that produce imaging like a CT scan or an MRI are also important. Doctors use these tools to help them to identify exactly where radiation needs to be applied. An MRI does not use x-rays or radiation and it is often used to produce imaging of the brain. A CT scan takes multiple images from different angles to allow you to see layers of a section of the body. Be sure to familiarize with any specific medical terminology you might be questioned about.