P2D-2 Development of a Novel Hand-Held Ultrasonic Probe Test Device

Although ultrasound transducer technology and system design have advanced dramatically over the last 25 years, the ability to assess transducer performance within the clinical setting has remained stagnant. Tissue-mimicking phantoms are still the most widely used quality assessment tool. Recent papers [Weigang, et al., 2003] have shown that images from tissue-mimicking phantoms are not sufficient to determine the existence of dead elements in an array even though missing elements result in "off axis" grating lobes that can materially degrade the quality of a clinical Doppler study. To address the need to detect dead elements or system channels, an inexpensive hand-held test device was developed. A special purpose multilayer broadband (1-20 MHz) PVDF transducer was developed. Transducer sensitivity is sufficient to produce a 100 mV_p-p output (non-amplified) from a single element of a 3 MHz array driven at 100 V_p-p The PVDF transducer is interfaced to a low noise preamplifier and signal detection system to indicate the presence of transmitted acoustic pulses from individual array elements. The device provides an LED indication to the user if pulses are detected. Further, the device injects a simulated echo that is displayed in the image and in Doppler, as a check of the ultrasound system\´s receiver chain. The PVDF transducer contact dimension is very small (0.15 times 2.8 mm) to allow identification of a single missing element in a fine pitch array. In a small-scale randomized trial, three trained operators tested four probe types on two imaging systems. All operators detected single missing elements on probes with pitches near 0.2 mm. There were no false positives or false negatives. The probe types tested included cardiac phased arrays, high frequency linear arrays and tightly curved transvaginal probes, encompassing a frequency range from 3-10 MHz. The device as developed has potential as a simple yet effective tool for quality assurance chec- ks within a clinical setting