Advanced ultrasonic tissue-typing and imaging based on radio-frequency spectrum analysis and neural-network classification for guidance of therapy and biopsy procedures. - Ernest J. Feleppa; Jeffrey A. Ketterling; Andrew Kalisz; Stella Urban; Christopher R. Porter; John W. Gillespie; Peter B. Schiff; Ronald D. Ennis; Cheng-Shie Wuu; William R. Fair (CARS, 2001)