Patient alignment system with external measurement and object coordination for radiation therapy system

A patient positioning system for a radiation therapy system having a plurality of components at least some of which are subject to uncontrolled movement, the positioning system comprising:

• a plurality of external measurement devices arranged to obtain position measurements of the plurality of components with respect to a substantially fixed frame of reference;
• a movable patient support configured to support a patient substantially fixed in position with respect to the patient support and to controllably position the patient in multiple translational and rotational axes;
• and
• a controller receiving patient position information from the plurality of external measurement devices and configured to provide translation and rotation movement commands to the movable patient support to align the patient in a desired pose such that the positioning system compensates for uncontrolled movement of the plurality of components.

A method of registering and positioning a patient for delivery of therapy with a system having a plurality of components, wherein at least certain of the components, including a patient positioner and a therapy nozzle, are subject to uncontrolled movement, the method comprising the steps of:

• positioning a patient in an initial treatment pose with the patient positioner;
• externally measuring the location of selected monuments of the plurality of components with respect to a substantially fixed frame of reference so as to define the initial treatment pose in the substantially fixed frame of reference;
• determining a difference vector between the measured initial patient pose and a desired patient pose;
• and
• providing movement commands to the patient positioner to bring the patient to the desired patient pose.