Finite beam-width ray model for geometric spectral broadening

Area of Science:

• Ultrasound physics
• Medical imaging technology
• Acoustic wave propagation

Background:

• Geometric spectral broadening is a phenomenon in ultrasound imaging.
• Accurate prediction of spectral width and maximum frequency is crucial for diagnostic ultrasound.
• Existing ray models for spectral broadening have limitations.

Purpose of the Study:

• To compare measured spectral width and maximum frequency with predictions from geometric spectral broadening ray models.
• To evaluate the accuracy of zero and finite beam-width models.
• To identify optimal parameters for ultrasound system calibration.

Main Methods:

• Spectral data were acquired using two linear array ultrasound systems on a string phantom.
• Beam width and Doppler aperture sizes were precisely measured with a needle hydrophone.
• Experimental measurements were compared against predictions from zero and finite beam-width models.

Main Results:

• Experimental data showed the best agreement with the finite beam-width model.
• The zero beam-width model exhibited significant errors, up to 50% for spectral width and 10% for maximum frequency.
• The finite beam-width model provided a more accurate prediction of spectral broadening.

Conclusions:

• The finite beam-width model is superior for calculating spectral width and maximum frequency in ultrasound.
• Ultrasound manufacturers can enhance measurement consistency by adjusting aperture size for a constant subtended angle and beam width.
• Optimizing aperture size can reduce variations in spectral broadening measurements across different machine locations.