Some embodiments include reception of a first instruction to enter an imaging mode, and, in response to the first instruction, automatic performance of at least one of: reduction of a focal spot size of a radiation beam, movement of a flattening filter out of a path of the radiation beam, replacement...http://www.google.fr/patents/US7397044?utm_source=gb-gplus-shareBrevet US7397044 - Imaging mode for linear accelerators
