Plane-parallel plate method of laser localization and laser positioning

摘要

Abstract: Rotating a plane-parallel glass plate in a laser beam can provide precise sub-millimeter beam translation useful for intraoperative localization and laser positioning. Fine control of beam translation by this method can aid in establishing laser-defined planes of a coordinate system used to locate patient anatomy or to align a stereotactic frame. To implement this method, laser dot or line projectors can be equipped with small motor-driven glass plates at or near their output ports. The author assembled an optical system consisting of a six mm thick crown glass plate, a visible diode laser projector and a 40-step stepper motor. This combination of simple and relatively inexpensive elements produces approximately one-half mm increments of beam translation over a five mm adjustment range. Benefits include fine control and freedom from perturbations caused by contact with adjustment thumbscrews. The addition of infrared remote control would allow easy adjustment of positioning lasers in hard-to-access areas of the operating or treatment room.!6