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The author presents an analytical solution to explain the acoustic scattering of a progressive high-order Bessel beam (HOBB) by an elastic sphere immersed in an ideal fluid. The discussed formulation is shown to be applicable for several other fluid and viscoeleastic, as well as coated spheres.

The article presents a theoretical analysis of the Langevin type acoustic radiation force exhibited by the interaction of a high-order Bessel beam with a rigid immovable sphere in an ideal fluid. The beams are shown to be extremely useful in designing new operating tweezers that can be further used in particle entrapment and manipulation applications.

A general theory is developed for the acoustic radiation force exerted by a standing and quasistanding Bessel sound field on a spherical particle immersed in water. The applications have included particle manipulation in microfluidic lab-on-chips as well as in reduced gravity environments.

The objective of this research is to prospectively evaluate the feasibility of vibroacoustography (VA) imaging in monitoring prostate cryotherapy in an ex vivo model. Baseline scanning of an excised human prostate is accomplished by a VA system apparatus in a tank of degassed water. Alcohol and dry ice mixture are used to freeze two prostate tissue samples. The frozen prostates are subsequently placed within the water tank at 27[degrees]C and rescanned. VA images were acquired at prescribed time intervals to characterize the acoustic properties of the partially frozen tissue. The frozen prostate tissue appears in the images as hypoemitting signal. Once the tissue thaws, previously frozen regions show coarser texture than prior to freezing. The margin of the frozen tissue is delineated with a well-defined rim. The thawed cryolesions show a different contrast compared with normal unfrozen prostate. In conclusion, this pilot study shows that VA produces clear images of a frozen prostate at different temperature stages. The frozen tissue appears as a uniform region with well-defined borders that are readily identified. These characteristic images should allow safer and more efficient application of prostatic cryosurgery. These results provide substantial motivation to further investigate VA as a potential modality to monitor prostate cryotherapy intraoperatively. Index Terms--Cryosurgery, prostate cancer, ultrasound, vibroacoustography (VA).

Analytical calculus based on Biot's theory is discussed for the transmission coefficient of a slab of porous material with an elastic frame. Findings reveal excellent agreement between theory and experiment.

The ultrasonic characterization of human cancellous bone samples is examined by solving the inverse problem using experimentally measured signals.

Vibro-acoustography method is explored for detecting and imaging brachytherapy metal seeds in gel phantoms. In a previous paper, we have shown that some immersed objects' resonance frequencies could be detected by vibro-acoustography. Here, we use this idea to optimize the vibro-acoustic excitation of two different sized brass seeds implanted in an agar gel phantom. In the experiments, the best excitation vibration frequencies were determined either by calculating fundamental resonance frequencies for each of the seeds or the experimental optimal resonance frequency of the gel. The resulting vibro-acoustography images demonstrate remarkable contrast in acoustic emission amplitude compared with images obtained at nonresonance frequencies. Results suggest the possible application of vibro-acoustography for directing prostate brachytherapy seed implantation treatment. Index Terms--Acoustic emission, brachytherapy, radiation force, resonance frequency, vibro-acoustography.

An alternative technique combining vibroacoustography and the finite element method for measuring the porosity parameter P and damping of a chalk sphere immersed in water is presented. This technique is based on the detection of the sphere resonance frequencies which will be compared to the finite element calculations. An optimization procedure based on the least squares method is performed in order to evaluate the “effective” Young’s modulus and damping parameters. Hence, porosity can be estimated by an inverse expression from the effective Young’s modulus. [ABSTRACT FROM AUTHOR]