Abstract: An apparatus and method for aligning a radiosurgery/stereotactic radiotherapy system. The system includes a linear accelerator, including a gantry and a collimator, a couch, and a stereotactic reference system mounted on the couch. The apparatus includes a laser measuring device mounted on the gantry, the laser measuring device having a laser generator element for generating a laser light beam and a laser displacement sensor. The apparatus also includes a reference fixture, attached to the stereotactic reference system, having at least one reflective surface for reflecting the laser light beam to the laser displacement sensor, upon which the laser displacement sensor measures the distance between the reflective surface and the laser measuring device.

Abstract: An apparatus and method for aligning a radiosurgery/stereotactic radiotherapy system. The system includes a linear accelerator, including a gantry and a collimator, a couch, and a stereotactic reference system mounted on the couch. The apparatus includes a laser measuring device mounted on the gantry, the laser measuring device having a laser generator element for generating a laser light beam and a laser displacement sensor. The apparatus also includes a reference fixture, attached to the stereotactic reference system, having at least one reflective surface for reflecting the laser light beam to the laser displacement sensor, upon which the laser displacement sensor measures the distance between the reflective surface and the laser measuring device.

Abstract: The disclosure is directed to a method and apparatus for determining, in three dimensions, the location, size, depth and width of tumors, lesions, abnormalities, structures, and the like, particularly useful for stereotactic surgery. The invention utilizes several beams which, when they intersect, allow for such measurements and calculations. The beam sources attach to a stereotactic frame.