A method and system is presented for treating moving target regions in a
patient's anatomy by creating radiosurgical lesions. The method includes
determining a pulsating motion of a patient separately from a determining
of a respiratory motion, and directing a radiosurgical beam, from a
radiosurgical beam source, to a target in the patient based on the
determining of the pulsating motion. Directing the radiosurgical beam to
the target may include creating a lesion in the heart to inhibit atrial
fibrillation. The method may further include determining the respiratory
motion of the patient, and compensating for movement of the target, due
to the respiratory motion and the pulsating motion of the patient, in the
directing of the radiosurgical beam based on the determining of the
respiratory motion and the determining of the pulsating motion.