Method and apparatus for tracking an internal target region without an implanted fiducial

An apparatus for tracking the location of an internal target region inside a patient, the apparatus comprising:

• an imaging device configured to generate a live image of a relevant volume that includes the internal target region;
• a memory unit storing a plurality of three-dimensional images wherein each of the three-dimensional images shows a pre-generated image, generated prior to treatment, of the relevant volume and the internal target region;
• and
• a processor coupled to the imaging device and the memory unit, the processor including a first set of computer-readable instructions for selecting a best three-dimensional image that most closely resembles the live image and a second set of computer-readable instructions for determining a position of the internal target region at the time the live image is generated based on the best three-dimensional image.

An apparatus for tracking the location of a target region inside a patient, the apparatus comprising:

• means for generating a plurality of first images of a relevant volume inside the patient, the relevant volume including the target region and each of the plurality of first images showing the target region;
• means for generating a live image of the relevant volume at a predetermined time during treatment;
• and
• means for determining a location of the internal target region at the predetermined time by identifying one of the plurality of first images that best matches the live image.

A method for locating during treatment an internal target region in a patient who is undergoing a motion, the method comprising:

• generating prior to treatment a plurality of first images of a relevant volume of a patient, the relevant volume including the target region and each of the plurality of first images showing the target region;
• generating a second image of the relevant volume at a predetermined time during treatment;
• and
• determining a location of the target region at the predetermined time by identifying one of the plurality of first images that best matches the second image.