An adaptation of the ultrasound transducer element test for multi-row arrays
Nicholas J Dudley1, Darren J Woolley2
1Radiation Protection & Radiology Physics, United Lincolnshire Hospitals NHS Trust, Greetwell Road, Lincoln LN2 5QY, UK; Multi-Medix Limited, Unit 56 Hayhill Industrial Estate, Barrow upon Soar, Leicestershire LE12 8LD, UK.
Purpose:
A simple "paperclip test" for the function of individual elements in a diagnostic ultrasound transducer array is widely performed and has been adapted for phased arrays. The aim of this study was to adapt the test further for multi-row transducer arrays.
Methods:
An embossing tool was used in place of the usual paperclip or metal rod and was slowly moved along the transducer array, attempting to isolate the signal from each row in turn. Phased array transducers were operated in M-mode. Non-functioning elements were identified by a reduction in amplitude of the reverberation line. The test was repeated several times for each transducer, ensuring that all non-functioning elements were identified and looking for consistency of results. 28 phased arrays and 5 linear/curvi-linear arrays in clinical use and 1 phased array and 1 linear array already identified as faulty by electronic transducer testing, and not in clinical service, were available for testing.
Results:
8 of the clinical phased arrays were found to have 1 or more faulty elements; 3 had only minor defects and 5 were replaced under warranty or service contract. The linear/curvi-linear arrays showed no fault. The adapted test showed the failed elements in the known faulty phased array, except at the end of the array, but weak elements were not detected. The faulty linear array had a block of failed outer elements which was identified by the test.
Conclusions:
The adapted test is capable of detecting non-functioning elements in multi-row arrays, but weak elements were not detected.
