The present invention provides a system and method for visualizing internal images of an anatomical body. Internal images of the body are acquired by an ultrasound imaging transducer. The position and orientation of the ultrasound imaging transducer is tracked in a frame of reference by a spatial determinator....http://www.google.ca/patents/US5957844?utm_source=gb-gplus-sharePatent US5957844 - Apparatus and method for visualizing ultrasonic images
