Transducer performance parameters and their influence on biometric results
Eleven transducers with working frequencies ranging from 5.1-11.9 MHz and bandwidths from 1.5 to 6.2 MHz were used on 3 commercial ultrasonic instruments with different operational principles to measure the length of a well defined phantom. In all cases, the true length could be reproduced with no dependency on frequency. The accuracy of biometric length determination was best in the instrument using high frequency counters and worse, when results were derived from the digitized video echogram. The dominant influence on biometric results is given by system sensitivity rather than transducer working frequency. From clinical measurements, a minimum transducer tone-burst sensitivity of ≈ −25 dB or ≈ 50 dB pulsemode sensitivity respectively has to be postulated in order to obtain acceptable biometric results.
KeywordsUltrasonic Transducer System Sensitivity Biometric Data International Electrotechnical Commission Nominal Frequency
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