The present invention provides an ultrasonic scanning transducer for use in an ultrasonic scanning system that examines an object by directing a series of ultrasonic waves into the object, receiving electrical signals related to the echoes generated by the ultrasonic waves when they strike acoustical interfaces within the object, and displaying the information borne by the electrical signals relating to the nature and location of acoustical interfaces within the object. The ultrasonic scanning transducer includes transducer elements secured to a permanent magnet mounted for rotational movement within the housing of the transducer and a stator assembly for rotating the transducers and magnet continuously in a single direction. The stator assembly receives a periodic signal having a zero average value and creates therefrom a unidirectionally rotating magnetic field which exerts a force on and rotates the permanent magnet.

Circuitry for reducing side to side jitter in an ultrasound imaging system using a transducer which is mechanically scanned back and forth to cover the area to be imaged. The circuitry includes a filter circuit for providing a correction signal to be added to the transducer position signal. The filter circuit provides a phase lead proportional to the rate of change of the transducer movement. This signal is scaled by a factor which varies linearly as the depth being imaged changes. The correction signal compensates for delays through the transducer positioning and driver circuitry and for depth dependant delays resulting from the movement of the transducer during the scanning operation.

An ultrasonic probe is positioned within a hollow body such as a pipe for detecting possible flaws in the body wall. The probe is designed for rotational and longitudinal movement in said pipe and includes an ultrasonic transmitter/receiver mounted eccentrically within a liquid filled chamber of the probe, so that transmitted impulses strike the inner wall of the pipe at such an angle that the angle of refraction of the sound wave in the material of the wall is always less than 90.degree..

A fully wetted ultrasound scanhead for medical applications is described in which the motor and the rotor are enclosed within a sealed housing filled with ultrasound coupling fluid. The invention includes a drive belt to drive the rotor from the motor, rather than a precision drive means. Speed adjustment means, including an encoder disk mounted on the rotor, provide feedback for an electronic speed controller. Accordingly, the speed of the motor can be adjusted as a direct consequence of the actual speed of the rotor.

Apparatus for the automatic examination of a patient's breast by echo mammography. A container for holding water has an opening for the receipt of the patient's breast, typically while the patient is in a prone position. A supporting arm is arranged in the container for movement of an ultrasonic head in a series of essentially semi-circular arcs around the breast. A series of sonogram sectional images are produced and are stored in a conventional manner. The opening can be covered with an elastic, diaphragm-like film or a network of strands, permeable to ultrasonic waves, to support the patient's breast in the water bath.