Patent ID: 8027715

Claim:
A computer-implemented method, comprising: receiving a plurality of data points representative of a corresponding plurality of positions over time of an external marker associated with respiration of a patient; receiving a plurality of images of an internal target of the patient, the plurality of images corresponding in time to the plurality of data points; developing, using a processing device, a non-linear correlation model of a non-linear path of movement of the target based on the plurality of data points and the plurality of images to correlate a plurality of positions of the internal target with the plurality of positions of the external marker, wherein developing the non-linear correlation model comprises: generating an inspiration approximation associated with the non-linear path of movement of the target over an inspiration interval of the non-linear path; generating an expiration approximation associated with the non-linear path of movement of the target over an expiration interval of the non-linear path; and generating one or more matching approximations to link the inspiration approximation and the expiration approximation.