Details

Autor(en) / Beteiligte

• Kreider, Wayne
• Yuldashev, Petr V.
• Maxwell, Adam D.
• Khokhlova, Tatiana D.
• Tsysar, Sergey A.
• Bailey, Michael R.
• Sapozhnikov, Oleg A.
• Khokhlova, Vera A.

Titel

Uncertainties in characterization of high-intensity, nonlinear pressure fields for therapeutic applications

Ist Teil von

• The Journal of the Acoustical Society of America, 2014-10, Vol.136 (4_Supplement), p.2250-2250

Erscheinungsjahr

2014

Quelle

American Institute of Physics (AIP) Journals

Beschreibungen/Notizen

• A fundamental aspect of developing therapeutic ultrasound applications is the need to quantitatively characterize the acoustic fields delivered by transducers. A typical approach is to make direct pressure measurements in water. With very high intensities and potentially shocks, executing this approach is problematic because of the strict requirements imposed on hydrophone bandwidth, robustness, and size. To overcome these issues, a method has been proposed that relies on acoustic holography and simulations of nonlinear propagation based on the 3D Westervelt model. This approach has been applied to several therapy transducers including a multi-element phased array. Uncertainties in the approach can be evaluated for both model boundary conditions determined from linear holography and the nonlinear focusing gain achieved at high power levels. Neglecting hydrophone calibration uncertainties, errors associated with the holography technique remain less than about 10% in practice. To assess the accuracy of nonlinear simulations, results were compared to independent measurements of focal waveforms using a fiber optic probe hydrophone (FOPH). When relative calibration uncertainties between the capsule hydrophone and FOPH are mitigated, simulations and FOPH measurements agree within about 15% for peak pressures at the focus. [Work supported by NIH grants EB016118, EB007643, T32 DK007779, DK43881, and NSBRI through NASA NCC 9-58.]