Is routine quality control of equipment still necessary in the case of digital ultrasound imaging systems?

Abstract

Is QC of Digital Ultrasound imaging equipment necessary? This question has been debated since Analogue US imaging systems were replaced by digital systems, which are more stable. These systems often include microprocessors, which carry out self-monitoring procedures with regards to the performance of the various sub-systems. This has led Radiology Personnel to question the need for a routine QC Program for US units. This research consisted of two QC case studies. The subjects in this case being the two US units in the Radiology Department at St. Luke's Hospital. (This test object has been proposed as the European Standard for EEC). A suitable QC protocol was set up based on the Cardiff Test object and regular QC testing or the two US units \Vas carried out over a period of 5 months. These US staff were asked to report any image degradation they could see in the images. This was done to check whether the QC program could detect degradation in performance before it was high enough to be visually defectable or before a major malfunction actually occurs. The results showed that the null hypothesis that stability of digital US imaging system (Ultramark 4) is such that no routine QC program is necessary should be rejected. Degradation in Sensitivity, Registration, Uniformity and Deadzone was detected by the QC program before observation was detected by US unit. therefore still necessary.