Patent ID: 8488862

Claim:
A method for determining a trajectory of a radiotherapy radiation source, the method comprising: obtaining a trajectory path model for a radiotherapy radiation source, the trajectory path model defined by at least one parameter; obtaining a plurality of discrete sample locations on the trajectory path model; providing a phantom having one or more fiducials at known reference positions in a coordinate system associated with the phantom; obtaining a projection image of the fiducials irradiated by the radiotherapy radiation source at each discrete location that samples the trajectory path model; determining, using a processor, a projection matrix from the projection image corresponding to each discrete location of the trajectory path model, the projection matrix determining the two dimensional coordinate of the projection in the projection image of a three dimensional point in the coordinate system associated with the phantom generated by the radiotherapy source at that discrete location in the trajectory path model; determining, using the processor, an actual coordinate of the radiotherapy radiation source in the coordinate system associated with the phantom at each of the discrete locations, based on the determined projection matrices; correlating the trajectory path model of the radiotherapy radiation source to the determined actual position of the radiotherapy radiation source at the plurality of discrete locations; and providing an output of at least one variance between the trajectory path model of the radiotherapy radiation source and the determined actual position of the radiotherapy radiation source at the plurality of discrete locations.