Acoustic propagation effects in therapeutic ultrasound

MR thermometry characterization of a hyperthermia ultrasound array designed using the k-space computational method

“…All points that related to a specific element were driven temporally in a sinusoidal fashion with a 1.2 MHz resonance frequency and a particular phase shift that compensated for its path length to a specific target. Greater details regarding the simulations with respect to the design of the array are described elsewhere [ 29 - 31 ].…”

“…Such simulations, however, do not capture the interaction of ultrasound with inhomogeneous tissue structures. Modeling of ultrasound wave propagation in inhomogeneous three-dimensional (3D) structure or medium over large length scales has become feasible using the k -space computational method [ 27 - 31 ]. This method solves the spatial terms of the wave equation by Fourier transformation to the spatial frequency domain, while temporal iterations are performed using a nonstandard finite difference approach using the k -t space propagator (where k represents the spatial frequency domain and t represents the time domain) [ 27 ].…”

High-Intensity Focused Ultrasound (HIFU) for Specific Therapeutic Treatments: A Literature Review

“…The diagram represents the physiologic concerns that must be considered when planning a treatment to an area of tissue and related diffusion of heat. 9 with 29 subjects with localized tumors. 13 This study treated 29 subjects, but only 10 were followed after HIFU therapy to surgical removal of the prostate.…”

“…This occurs because of the tissue's ability to absorb energy and the tendency for this energy to diffuse to a lower strength as it travels farther away from the source. 9 The intensity of the beam is also governed by the density of the tissue that it is traveling through. For example, bone absorbs more energy than soft tissues, which is critical when determining the dosage required for therapeutic effects.…”