A Two-Dimensional Ultrasonic Scanning System

Abstract

A two-dimensional scanning system has been developed for use with an ultrasonic pulse echo diagnostic unit. The output is a cross-sectional display on a memory CRT. The main application of this apparatus is in the study of the structure of the soft tissue and bones of the limbs. It is anticipated that the system may be used to study the healing of fractures and to outline soft tissue structures not adequately represented by radiographs.

The object to be studied is placed in a tank filled with water. A transducer is mounted on a circular ring and located such that the transducer face is below the surface of the water and perpendicular to the object to be studied. The ultrasonic pulse path is a diameter of this mounting ring. As the transducer is rotated on this ring, the direction of the CRT trace rotates correspondingly to produce a one-to-one maping on the face of the CRT of the area seen by the transducer. 

The CRT beam is controlled by an electronic transducer position sensing circuit. This circuit maintains the proper trace direction, relative to the transducer, while maintaining a constant trace length and beam velocity. The CRT beam is unblanked whenever an echo is received, producing light spots on the CRT at all the interfaces of the sample under study. With a 360-degree rotation of the transducer, a cross-section of the sample is displayed on the face of the storage CRT.