Radiation therapy system using plural treatment plans

A radiation therapy system comprising:

• a radiation source for providing radiation to a structure;
• a controller comprising a processor, and adapted to control the radiation source in accordance with a treatment plan;
• a localization unit for determining a position of the structure within a body during a radiation treatment;
• a tangible, non-transitory computer readable medium that stores instructions, which when executed by the processor, cause the processor to perform a method, comprising:
• providing to the controller a plurality of treatment plans, each of the plurality of treatment plans being associated with one of a plurality of predefined possible positions of a reference point of the structure and the predefined possible positions being regularly distributed on at least one predefined surface;
• determining the position of the reference point of the structure during the treatment;
• and
• selecting a treatment plan, which is associated with a predefined possible position having a smallest distance to the determined position of the reference point of the structure, for controlling the radiation source in response to a detection of the position.

A tangible, non-transitory computer readable medium that stores instructions, which when executed by a processor, cause the processor to:

• provide to a controller a plurality of treatment plans, each of the plurality of treatment plans being associated with one of a plurality of predefined possible positions of a reference point of a structure and the predefined possible positions being regularly distributed on at least one predefined surface;
• determine a position of the reference point of the structure during a radiation treatment;
• and
• select a treatment plan, which is associated with a predefined possible position having a smallest distance to the determined position of the reference point of the structure, for controlling a radiation source in response to a detection of the position.