Hoffmann-la Roche Inc.

Heinz Hoffmann

Christoph B Burckhardt

Pierre-Andre Grandchamp

Rainer Fehr

Pierre-Andre Grandechamp

A method for producing cross-sectional images using an ultrasonic imaging unit operating on the pulse-echo principle, which unit includes a transducer system having a stationary elongated array of adjacent transducer elements with transverse electrode segments adjacent one another on one side of the array. Successively and cyclically selected groups of adjacent elements are energized to produce an ultrasonic beam as a result of pulsed signals being applied to the corresponding electrode segments. Focussing of the ultrasonic beam produced by each group of the transducers is effected by having the transmitter signals applied to the electrode segments or subgroups thereof, and/or the echo-signals derived by the electrode segments from the reflected energy, time shifted relative to one another, in which each transmitter or echo-signal has a time shift associated thereto which is a function of the distance between the corresponding electrode segments (or subgroups of segments) and the center of the group of transducers.

Method and apparatus for producing cross-sectional images using

An ultrasonic echo sounding technique for reducing unwanted echoes from reflectors outside the focal line of a focused ultrasonic field is disclosed. In this technique at least two pulse-defined ultrasonic waves are successively transmitted. The amplitudes of the said waves are functions of an angle .phi. which is generated about the axis of the source of ultrasound. Echoes from the reflected waves are received from reflectors both on and outside the focal line and multiplied by an amplitude factor which is a function of the above mentioned angle .phi.. Echo signals associated with echoes having the same transit time are then added together.

Echo sounding technique

An improved method and apparatus for reducing the echoes from reflectors disposed outside the focal line in an echo-sounding process using an ultrasonic field focusing in a focal line. A pulsed ultrasonic wave is transmitted having a cross-sectional area corresponding to one or more annularly arranged transducer segments having a total azimuth angle of less than 360.degree.. Echoes of the transmitted wave are received from the spatial region corresponding to at least a part of other annular transducer segments, which complement the annular segments of the cross-sectional area of the transmitted ultrasonic pulse to form a complete ring. The radiation or receiving surfaces of the transducer segments forming the transducer ring are inclined toward the axis of the ring.

Suppression of out-of-focus echoes in ultrasonic scanning

An apparatus for focusing ultrasonic waves in a focal line by an ultrasonic optical system having at least one rotation-symmetrical, non-spherical acoustical reflection surface which together with an ultrasonic transducer element transmits an at least partially convergent ultrasonic field having an annular cross-section.

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Grenzach, Germany

Heinz Hoffmann