Measurement issues in quantitative ultrasonic imaging

Ultrasonic imaging of "flesh and blood" is vulnerable to the natural variability of these media: the speed of sound is not known, not constant, and not amenable to calibration using simply shaped manufactured samples. When images of high dimensional accuracy are needed, as for image guided surgery, the "average" or "typical" values used in diagnostic ultrasound may not be good enough. In this paper, we identify the main sources of uncertainty, and we suggest and model experimental approaches to in situ calibration.