Aspects for verifying an accessory beam limiting device position for a radiotherapy treatment session are described. Included in a system aspect is a radiotherapy treatment device, the radiotherapy treatment device including an accessory holder. A beam limiting device for establishing a treatment area,...http://www.google.ca/patents/US6466644?utm_source=gb-gplus-sharePatent US6466644 - Method and system for verification of different types of beam limiting devices in a linear accelerator utilized for radiotherapy
