A computerized system for measuring the acoustic output from diagnostic ultrasound equipment

The measurement arrangement, which complies with the requirements of the US Food and Drug Administration, consists of a positioning system with a full range of degrees-of-freedom and a digital oscilloscope, both under complete computer control. The acoustic pressure-time waveform is recorded using membrane-type and needle-type polyvinylidene fluoride (PVDF) hydrophone probes. The overall bandwidth of the system depends on the hydrophone probe used and can range up to 100 MHz. A complete description of the system and the measurement procedures is given, along with a brief discussion of the various factors which affect measurement uncertainty. The largest overall uncertainty of the same associated with acoustic intensity measurements was determined to be no greater than 20% for I(sppa) and 25% for I(spta) (spatial peak pulse average intensity and spatial-peak temporal-average intensity, respectively). Other applications of the system include transducer characterization and research work in ultrasound dosimetry and bioeffects.