1. A radiosurgical method for treating a patient body having a target tissue, the target tissue associated with a disease state, the method comprising: acquiring planning image data from the target tissue; planning an ionizing radiation treatment of the target tissue using the planning image data so as to mitigate the disease; implanting a position surrogate within the body by advancing the position surrogate and an elongate flexible body through a blood vessel, releasably coupling the position surrogate to the target tissue so that the position surrogate exhibits movement of the target tissue, detaching the position surrogate from the flexible body and removing the flexible body from the patient body; remodeling the target tissue by directing the planned radiation from outside the body toward the target tissue with reference to the implanted position surrogate thereby mitigating the disease; and monitoring a heartbeat cycle from the body while acquiring the planning image data, and acquiring a time series of three dimensional image data sets distributed throughout the heart beat cycle so as to indicate movement of the target tissue with the heartbeat cycle; wherein the planning of the treatment comprises: identifying radiation sensitive collateral tissue, and determining a series of radiation beams suitable for providing a desired radiation dose in the target tissue without excessively irradiating the collateral tissue; and wherein the remodeling of the target tissue is performed by: monitoring the heartbeat cycle from the body; wherein monitoring the heartbeat cycle from the body comprises obtaining an electrogram of the heart, and tracking at least a portion of the movement of the target tissue in response to the monitored heartbeat cycle while directing the radiation to the target tissue using the time series of datasets.