ACOUSTIC FIELD OF A MEDICAL ULTRASOUND PROBE OPERATED IN CONTINUOUS-WAVE MODE INVESTIGATED BY TV HOLOGRAPHY

Time-averaged TV holography has been shown ta be a useful technique fo r investigating acoustic fields in transparent media. The theory of ti me-averaged TV-holography measurements of ultrasonic fields in water i s described. Projections of the phase and the amplitude of a 3.25-MHz ultrasonic field from an annular ultrasound probe operated in cw mode are presented. Quantitative measurements with a spatial resolution of better than 100 mu m have been obtained. A set of such projections may he processed into a three-dimensional mapping of the phase and the am plitude of the acoustic field by tomographic techniques. This process is described, and an example of a tomographic reconstruction of the sa me ultrasonic field is presented. (C) 1998 Optical Society of America OCIS codes: 110.6960, 120.5050, 120.6160.