An optimum design of an ultrasonic transducer array for medical imaging

Abstract

In this paper, it is shown how to optimize an ultrasonic transducer array system, such that each array element receives a maximum reflected signal from that part of the object (to be imaged) which is directly lying in front of it, while it receives the minimum signal from the rest of the object. According to this concept, it is expected that the image quality will become better. Also, it is shown that the object should not lie directly in contact with the array, but it rather should be at a certain specific distance in order to get a maximum 'useful' signal. Thus if a coplanar circular receiving transducer is moved away from an identical transmitting one, it is shown that the receiving transducer passes by successive positions of maximum and minimum echoes which are induced by a flat metallic reflector situated at a predetermined specific distance. The first point of minimum echo is taken to be the optimum position for the receiving transducer when designing a transducer matrix for imaging applications. Theoretical as well as experimental results are obtained and compared with each other, and a rather fair coincidence is found between both kinds of results.