A simple uniformity test for ultrasound phased arrays

Purpose: It is difficult to test phased array ultrasound transducers for non functioning elements. We aimed to modify a widely performed test to improve its ease and effectiveness for these arrays. Methods: A paperclip was slowly moved along the transducer array, with the scanner operating in Mmode, imaging at a fundamental frequency with automatic gain and grey scale adjustment disabled. Non- functioning elements are identified by a dark vertical line in the image. The test was repeated several times for each transducer, looking for consistency of results. 2 transducers, with faults already shown by electronic transducer testing, were used to validate the method. 23 transducers in clinical use were tested. Results: The results of the modified test on the 2 faulty transducers agreed closely with electronic transducer testing results. The test indicated faults in 5 of the 23 transducers in clinical use: 3 with a single failed element and 2 with non- uniform sensitivity. 1 transducer with non- uniform sensitivity had undergone lens repair; the new lens was visibly non- uniform in thickness and further testing showed a reduction in depth of penetration and a loss of elevational focus in comparison with a new transducer. Conclusions: The modified test is capable of detecting non- functioning elements. Further work is required to provide a better understanding of more subtle faults. (C) 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.