OUTPUT LEVELS AND BIOEFFECTS INDEXES FROM DIAGNOSTIC ULTRASOUND EXPOSURE DATA REPORTED TO THE FDA

As part of the Section 510(k) requirements of the 1976 Medical Device Amendments to the Federal Food, Drug, and Cosmetic Act, manufacturers of diagnostic ultrasound devices submit acoustic output data to the U.S. Food and Drug Administration. Because this information is pertinent to the assessment of any potential bioeffects due to ultrasound exposure, we have summarized the measurement data processed during 1990 and 1991. Exposure data were summarized for real-time B-mode and M-mode, general pulsed Doppler, peripheral vascular (PV) pulsed Doppler, and color flow Doppler. Exposure quantities included peak rarefactional and compressional pressures, spatial-peak pulse-average and spatial-peak temporal-average intensities (both water and derated values), and power. Also, where data permitted, mechanical and thermal indices were calculated. Ranges, means, medians, and standard deviations were categorized for the exposure quantities and indices. In general the temporal-average values (including indices) were higher in Doppler modes than in B/M imaging modes. Differences among the temporal-peak exposure quantities and indices were less distinct, although values tended to be higher in the PV and color flow Doppler categories. These data, along with comparable results collected by others, provide a means to relate the output of current devices to levels of exposure relevant to ultrasound-induced biological effects.