Interaction of a high-order Bessel beam with a submerged spherical ultrasound contrast agent shell – Scattering theory

Mitri, F.G.

doi:10.1016/j.ultras.2009.09.003

Cited by 17 publications

(16 citation statements)

References 49 publications

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“…as an initial example, the 3-d scattering patterns for the resonance form function corresponding to previous results for the axial scattering of an albunex shell [43,Figs. 5a and 5b] centered on a zero-order Bessel beam are computed.…”

Section: B Numerical Results and Discussionsupporting

confidence: 53%

“…as an example, the shell is assumed to have an outer radius a = 3.5 μm and a thickness of 105 nm (i.e., b/a = 0.97); the shell's material is composed of an albuminoidal protein (ρ s = 1100 kg/m 3 ; c l = 7458 m/s; c s = 284 m/s) [43], [53], [54], and the internal core of the shell is filled with perflurorpropane gas [55] (ρ f int = 90 kg/m 3 ; c f int = 92 m/s). Following the previous study on axial scattering by an albunex shell [43], it has been found that the soft background should be subtracted from the total form function for proper characterization/display of the shell's resonances.…”

Section: B Numerical Results and Discussionmentioning

confidence: 99%

“…However, for shells or spheres with density comparable to the external fluid, or for a dense but quite thin shell, the intermediate background has been adequately introduced to properly identify the resonances [50]. The rsT formalism has been applied to the case of an elastic sphere [21], [23] and a contrast agent spherical shell [43] centered on the axis of a high-order Bessel vortex beam.…”

Section: B Resonance Form Function In the Far-fieldmentioning

confidence: 99%

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Generalized theory of resonance excitation by sound scattering from an elastic spherical shell in a nonviscous fluid

Mitri

2012

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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This work presents the general theory of resonance scattering (GTRS) by an elastic spherical shell immersed in a nonviscous fluid and placed arbitrarily in an acoustic beam. The GTRS formulation is valid for a spherical shell of any size and material regardless of its location relative to the incident beam. It is shown here that the scattering coefficients derived for a spherical shell immersed in water and placed in an arbitrary beam equal those obtained for plane wave incidence. Numerical examples for an elastic shell placed in the field of acoustical Bessel beams of different types, namely, a zero-order Bessel beam and first-order Bessel vortex and trigonometric (nonvortex) beams are provided. The scattered pressure is expressed using a generalized partial-wave series expansion involving the beam-shape coefficients (BSCs), the scattering coefficients of the spherical shell, and the half-cone angle of the beam. The BSCs are evaluated using the numerical discrete spherical harmonics transform (DSHT). The far-field acoustic resonance scattering directivity diagrams are calculated for an albuminoidal shell immersed in water and filled with perfluoropropane gas, by subtracting an appropriate background from the total far-field form function. The properties related to the arbitrary scattering are analyzed and discussed. The results are of particular importance in acoustical scattering applications involving imaging and beam-forming for transducer design. Moreover, the GTRS method can be applied to investigate the scattering of any beam of arbitrary shape that satisfies the source-free Helmholtz equation, and the method can be readily adapted to viscoelastic spherical shells or spheres.

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Section: B Numerical Results and Discussionsupporting

confidence: 53%

Section: B Numerical Results and Discussionmentioning

confidence: 99%

Section: B Resonance Form Function In the Far-fieldmentioning

confidence: 99%

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Generalized theory of resonance excitation by sound scattering from an elastic spherical shell in a nonviscous fluid

Mitri

2012

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…The specific "root" angles are associated with specific nth partial waves such that the suppression of a particular resonance and its contribution to the scattering is therefore attainable by judicious selection of the half-cone angle ␤ to correspond to on the P n ͉m͉ ͑cos ␤͒ roots. This has been confirmed in the context of the acoustic scattering 13,14,16 and radiation forces 31,32 of Bessel vortex ͑or helicoidal͒ beams in suppressing resonances and may be potentially extended to the case of HOBTBs.…”

Section: Numerical Examples and Discussionmentioning

confidence: 62%

“…Appropriate selection of the beam's parameters, such as the focus, waist, divergence, directionality, collimation, etc., or more generally the beam's type ͓i.e., diffracting, ͑i.e., Gaussian, Bessel-Gaussian, LaguerreGaussian, fractional Bessel, etc.͒ versus nondiffracting, ͑i.e., Bessel of integer order, high-order Bessel Beam of fractional type ␣, etc.͔͒, may be used to advantage to enhance or suppress the scattering. [12][13][14][15][16][17] Ideal nondiffracting beams are proper solutions of the homogeneous ͑source-free͒ Helmholtz equation, 18 for which the transverse pressure ͑or intensity͒ distribution profile remains unchanged during wave propagation. In practice, a very close approximation to an ideal nondiffracting beam can be achieved experimentally by a Gaussian transmittance apodization to produce a "limited-diffracting"-Gauss beam.…”

Section: Introductionmentioning

confidence: 99%

Linear axial scattering of an acoustical high-order Bessel trigonometric beam by compressible soft fluid spheres

Mitri

2011

Journal of Applied Physics

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History force on coated microbubbles propelled by ultrasound Phys. Fluids 21, 092003 (2009) Ultrasound-order director fluctuations interaction in nematic liquid crystals: A nuclear magnetic resonance relaxometry study J. Chem. Phys. 118, 9037 (2003) Silicon micromachined ultrasonic immersion transducers Appl. Phys. Lett. 69, 3674 (1996) Electromagnetic excitation of ultrasound in electrolytes Appl. Phys. Lett. 69, 3327 (1996) Additional information on J. Appl. Phys. The acoustic scattering properties of nondiffracting high-order Bessel trigonometric beams ͑HOBTBs͒ by fluid spheres are investigated. The three-dimensional directivity acoustic scattering patterns of hexane, red blood, and mercury soft spheres immersed in water and centered on the beam axis of wave propagation are presented and discussed. HOBTBs belong to the family of nondiffracting beams and are proper solutions of the homogeneous ͑source-free͒ Helmholtz equation. Closed-form analytical solutions for the incident and scattered pressure fields are provided. The far-field acoustic scattering field is expressed as a partial wave series involving the scattering angle relative to the beam axis, the order, and the half-conical angle of the wave number components of the HOBTB. The properties of the acoustic scattering by fluid spheres are discussed and numerical computations with animated graphics show exciting scattering phenomena that are especially useful in applications related to particle entrapment and manipulation of soft matter using acoustic HOBTBs. Other potential applications may include medical or nondestructive ultrasound imaging with contrast agents, or monitoring of the manufacturing processes of sample soft matter systems with HOBTBs.

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Numerical investigation of the acoustic scattering problem from penetrable prolate spheroidal structures using the Vekua transformation and arbitrary precision arithmetic

Gergidis

Kourounis

Mavratzas³

et al. 2018

Math Methods in App Sciences

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A complete set of radiating “outwards” eigensolutions of the Helmholtz equation, obtained by transforming appropriately through the Vekua mapping the kernel of Laplace equation, is applied to the investigation of the acoustic scattering by penetrable prolate spheroidal scatterers. The scattered field is expanded in terms of the aforementioned set, detouring so the standard spheroidal wave functions along with their inherent numerical deficiencies. The coefficients of the expansion are provided by the solution of linear systems, the conditioning of which calls for arbitrary precision arithmetic. Its integration enables the polyparametric investigation of the convergence of the current approach to the solution of the direct scattering problem. Finally, far‐field pattern visualization in the 3D space clarifies the preferred scattering directions for several frequencies of the incident wave, ranging from the “low” to the “resonance” region.

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Interaction of a high-order Bessel beam with a submerged spherical ultrasound contrast agent shell – Scattering theory

Cited by 17 publications

References 49 publications

Generalized theory of resonance excitation by sound scattering from an elastic spherical shell in a nonviscous fluid

Generalized theory of resonance excitation by sound scattering from an elastic spherical shell in a nonviscous fluid

Linear axial scattering of an acoustical high-order Bessel trigonometric beam by compressible soft fluid spheres

Numerical investigation of the acoustic scattering problem from penetrable prolate spheroidal structures using the Vekua transformation and arbitrary precision arithmetic

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