Spatially uniform harmonic acoustic radiation force excitation using one-dimensional linear array

2015 ◽  
Vol 137 (4) ◽  
pp. 2314-2315
Author(s):  
Mahdi Bayat ◽  
Azra Alizad ◽  
Mostafa Fatemi
Keyword(s):  
Linear Array ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
One Dimensional ◽  
Force Excitation

scholarly journals Acoustic tweezing of microparticles in microchannels with sinusoidal cross sections

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elnaz Attar Jannesar ◽  
Hossein Hamzehpour
Keyword(s):  
Cross Sections ◽  
Critical Size ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Biotechnological Applications ◽  
One Dimensional ◽  
Wave Resonance ◽  
Half Wave ◽  
Simulation Results

AbstractAcoustic tweezing of bioparticles has distinct advantages over other manipulation methods such as electrophoresis or magnetophoresis in biotechnological applications. This manipulation method guarantees the viability of the bio-particles during and after the process. In this paper, the effects of sinusoidal boundaries of a microchannel on acoustophoretic manipulation of microparticles are studied. Our results show that while top and bottom walls are vertically actuated at the horizontal half-wave resonance frequency, a large mono-vortex appears, which is never achievable in a rectangular geometry with flat walls and one-dimensional oscillations. The drag force caused by such a vortex in combination with the tilted acoustic radiation force leads to trapping and micromixing of microparticles with diameters larger and smaller than the critical size, respectively. Simulation results in this paper show that efficient particle trapping occurs at the intermediate sinusoidal boundary amplitudes. It is also indicated that in a square-sinusoidal geometry there are two strong vortices, instead of one vortex. Sub-micrometer particles tend to be trapped dramatically faster in such a geometry than in the rectangular-sinusoidal ones.

Observations of Tissue Response to Acoustic Radiation Force: Opportunities for Imaging

2002 ◽  
Vol 24 (3) ◽  
pp. 129-138 ◽  
Author(s):  
Kathryn Nightingale ◽  
Rex Bentley ◽  
Gregg Trahey
Keyword(s):  
Acoustic Radiation ◽  
Ex Vivo ◽  
Ultrasonic Transducer ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Tissue Response ◽  
Acoustic Radiation Force Impulse ◽  
Ex Vivo Tissues ◽  
Force Excitation ◽  
Arfi Imaging

Acoustic Radiation Force Impulse (ARFI) imaging is a method for characterizing local variations in tissue mechanical properties. In this method, a single ultrasonic transducer array is used to both apply temporally short localized radiation forces within tissue and to track the resulting displacements through time. In an ongoing study of the response of tissue to temporally short radiation force excitation, ARFI datasets have been obtained of ex vivo tissues under various focal configurations. The goal of this paper is to report observations of the response of tissue to radiation force and discuss the implications of these results in the construction of clinical imaging devices.

Quantitative Images of Elastic Modulus Using Tissue Dynamics in the Region of Impulsive Acoustic Radiation Force Excitation

2009 ◽  
Author(s):  
Mark L. Palmeri ◽  
David Xu ◽  
Michael Wang ◽  
Kathryn Nightingale
Keyword(s):  
Shear Modulus ◽  
Shear Wave ◽  
Acoustic Radiation ◽  
Simulated Data ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Excitation Beam ◽  
Shear Wave Speed ◽  
Shear Elasticity ◽  
Force Excitation

Focused, impulsive, acoustic radiation force excitations can generate shear waves with microns of displacement in tissue. The speed of shear wave propagation is directly related to the tissue’s shear modulus, which can be correlated with tissue pathology to diagnose disease and to follow disease progression. Shear wave speed reconstruction has conventionally been measured over spatial domains that are spatially-offset from the region of excitation (ROE). While these methods are very robust in clinical studies characterizing large, homogeneous organs, their spatial resolution can be limited when generating quantitative images of shear elasticity. The ROETTP algorithm measures time-to-peak (TTP) displacements along the axis-of-symmetry in the ROE of an impulsive acoustic radiation force excitation. These TTP displacements are inversely proportional to shear stiffness and are dependent on the excitation-beam geometry. Lookup tables (LUTs) specific to an excitation/displacement tracking transducer configuration were generated from simulated data, and shear stiffnesses were estimated from experimental data as a function of depth using the LUTs. Quantitative ROETTP shear elasticity images of spherical inclusions in a calibrated tissue-mimicking phantom have been generated. Shear wave reflections and interference can lead to an underestimation of the absolute reconstructed shear modulus (20–25%), but the ratio of absolute shear stiffnesses is well-preserved (3.3 vs. 3.5).

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