Effectiveness evaluation of extrapolation to frequency response of hydrophone sensitivity for measuring instantaneous acoustic pressure of diagnostic ultrasound

Abstract

Precise measurement techniques of instantaneous acoustic pressure using the frequency response of hydrophone sensitivity have been investigated to evaluate the safety of diagnostic ultrasound. This technique requires the frequency range of sensitivities broader than bandwidth of the ultrasound. But available frequency range of sensitivities on a calibration certificate is limited. Extrapolation to the frequency range of certificated sensitivities might be an effective approach; however, the effectiveness of such extrapolation has not been sufficiently studied. In this paper, we propose a quantitative method for evaluating the effectiveness of such extrapolation, which is characterized by showing the narrowest frequency range of certificated hydrophone sensitivities necessary for precise measurement of instantaneous acoustic pressure in diagnostic ultrasound. The evaluation results showed that the extrapolation was generally effective for precise measurement using the certificated hydrophone sensitivity with a narrower frequency range than the bandwidth of the measured ultrasound.

Augmenting Immunogenic Cell Death and Alleviating Myeloid‐Derived Suppressor Cells by Sono‐Activatable Semiconducting Polymer Nanopartners for Immunotherapy

“…The frequency of US used in this study was 1.0 MHz, no higher than that of diagnostic US (1.0–20.0 MHz). [ 28 ] In addition, US energy and irradiation time during sono‐activation were optimized to achieve ideal activation efficacy and therapeutic outcomes, without causing obvious side effects. The low frequency, energy, and irradiation time of US will promote its application transformations into clinical trials.…”

Improvement of extrapolating frequency response of hydrophone sensitivity using numerical simulation that includes assumptions about materials and construction of hydrophone for measuring instantaneous acoustic pressure of diagnostic ultrasound

“…The deconvolution method essentially includes the interpolation and extrapolation of the frequency response of hydrophone sensitivity and the frequency filtering of the instantaneous acoustic pressure waveform. 20) The frequency response of hydrophone sensitivity within the frequency range of certificated sensitivities was interpolated using a cubic spline, as used in previous studies, 10,17) to compensate for the mismatch between the frequency interval for the calibration frequency (1 MHz) and that for the frequency spectrum ( f s /N = 0.2 MHz).…”

“…[10][11][12][13][14][15][16][17][18][19] Based on a regulation of an international standard for measuring ultrasonic fields using a hydrophone, it is guessed that a broad frequency range of certificated hydrophone sensitivity of 0.5-8 times the center frequency of the measured ultrasound is necessary for the deconvolution method. 20,21) The center frequency of diagnostic ultrasound is about 1-20 MHz. 22) A hydrophone sensitivity of 0.5-160 MHz is required to measure diagnostic ultrasound using the deconvolution method.…”

“…We previously compared effectiveness of two approaches for implementing the deconvolution method. 20) One is extrapolating the frequency responses of certificated hydrophone sensitivity using constants that are equal to extremes of the frequency range of certificated sensitivity (hereafter called extrapolation using constants) for compensating a lack of certificated sensitivity. The other is applying a frequency filter to the hydrophone output voltage to cut frequencies out of the range of certificated sensitivities (hereafter called filtering treatment).…”