An arrangement for effecting ultrasonic-echo encephalography, including at least two ultrasonic heads, as well as a recording arrangement for the ultrasonic waves which are received from the skull of a patient, and having at least one marking device associated therewith for marking the position of the...http://www.google.fr/patents/US4043321?utm_source=gb-gplus-shareBrevet US4043321 - Arrangement for ultrasonic-echo encephalography
