Image Guided Radiation Therapy
Image Guided Radiation Therapy is again a form of radiation therapy where the position of the patient prior to irradiation can be accurately tracked, and subsequently corrected for in the event that the patient is improperly positioned relative to the radiation beams. The image guidance usually is achieved using Kilo-Voltage, or KV, "images of the patient, which allows for very accurate visualization of the patient's anatomy. On some occasions, little metal seeds, or fiducials, will be implanted into the tumor so that these seeds can act as a guide for the radiation fields under image guidance.
A more comprehensive form of image guidance involves the use of "Cone Beam CT", or CBCT. CBCT is a full, 3D, volumetric CT scan of the region to be treated. Similar to a conventional CT scan, the CBCT allows the physician to view in 3 dimensions the area to be treated immediately prior to the actual treatment. This allows for a more exact positioning of the patient in reference to the treatment machine. "