Path planning and collision avoidance for movement of instruments in a radiation therapy environment

A path planning and collision avoidance system for a radiation therapy system having fixed and movable components and selectively delivering a radiation therapy beam along a beam axis, the positioning system comprising:

• a plurality of external measurement devices arranged to obtain position measurements of the components so as to provide location information;
• a movable patient support configured to support a patient substantially fixed in position with respect to the patient support and controllably position the patient in multiple translational and rotational axes;
• and
• a controller receiving position information from the plurality of external measurement devices and providing movement commands to the movable patient support to automatically align the patient in a desired pose and determining a corresponding movement envelope wherein the controller evaluates the movement envelope and inhibits movement of the patient support if a collision is indicated else initiates the movement.

A method of registering and positioning a patient for delivery of therapy with a system having fixed and at least one movable components, the method comprising the steps of:

• positioning a patient in an initial treatment pose with a controllable patient positioner;
• externally measuring the location of selected points of the fixed and at least one movable components;
• determining a difference vector between the observed initial patient pose and a desired patient pose;
• determining corresponding movement commands and a movement trajectory for the patient positioner to bring the patient to the desired patient pose;
• and
• comparing the movement trajectory with the measured locations of the selected points of the fixed and at least one movable components so as to inhibit movement of the patient positioner if a collision is indicated.