Two-dimensional diffraction scanning of normal and cancerous human hepatic tissue in vitro.

A technique and associated equipment are described which investigate the acoustic signals backscattered from small tissue volumes and interrogated over a solid angle of transmitter/receiver positions. This two-dimensional diffraction technique produces acoustic scatter maps termed, by us "interferograms", which are analysed to determine their usefulness in discriminating between normal, freshly excised liver tissue and cancerous tissue within the intact organ. The "interferograms" are collected at three different narrow-band frequencies and have been used in investigating 26 normal liver and 13 liver tumour samples. The preliminary results indicate that this novel technique has a 97% success in discriminating normal liver from tumour, compared to an 87% success achieved by two observers when scoring conventional sector B-scan images of the same tissue regions.