Method for monitoring the accuracy of tissue motion prediction from surrogates

A method of indirectly monitoring the position of a target inside a body, the method comprising:

• generating a target position model that predicts a location of a target of a patient and generating an error prediction model used to determine accuracy of the predicted location of the target;
• generating position data based on the respective positions of one or more surrogate devices coupled to the patient;
• predicting a location of the target using the target position model and the position data;
• delivering a medical treatment to the patient based on the target position model during a treatment period;
• determining whether the predicted location of the target has deviated from the actual location of the target using only the position data and the error prediction model during the treatment period;
• and
• when the predicted location of the target has deviated from the actual location of the target, pausing delivering of the medical treatment, updating the target prediction model, and resuming the delivering of the medical treatment.