Interlaboratory comparison of ultrasonic attenuation and speed measurements.

A set of test samples, all containing ultrasonically equivalent tissue-mimicking material, was produced and measurements of ultrasonic speed and ultrasonic attenuation coefficients were made at seven laboratories using various techniques. The ultrasonic speed values agree well with one another, having a spread of about 0.3 per cent; thus, speed values for tissue parenchyma appearing in the literature are likely to be accurate. Values of ultrasonic attenuation coefficients agree fairly well with one another, with differences between individual values and the group mean of generally less than 20 per cent of the group mean.