Method for determining the SATA and SAPA intensities for real-time ultrasonographic scanning modes

Determination of a complete set of sonographic exposure parameters is desirable for any clinical ultrasound unit and is particularly important in controlled studies of biologic effects. When the exposure system is a diagnostic real-time scanner operating in autoscan mode, the determination of two of these parameters, the spatial average-temporal average (SATA) and the spatial average-pulse average (SAPA) intensities, is not straightforward because of the spatial overlap of successive propagating pulses. A method is described for determining these intensities for autoscan operation. The primary tool in the method is a digital oscilloscope, which supports pretrigger recording and configuring of the oscilloscope's memory into segments that can record rapidly occurring successive pulses, each segment recording one pulse. Results for a few commercially available real-time scanning systems are presented.