A method of planning path for a surgical instrument is provided for use during a surgical procedure. The method includes identifying a treatment target in images of a patient to be treated during a surgical procedure, determining dimensions of the patient, a surgical instrument, and an external obstruction, and determining a path to guide the surgical instrument to the treatment target during the surgical procedure. The surgical instrument is configured to be used during the surgical procedure. The external obstruction is an object external to the patient's body that interferes with one or more potential paths of the surgical instrument. The path is determined such that the surgical instrument avoids the external obstruction based on the determined dimensions of the surgical instrument and the determined dimensions of the external obstruction.