Prospective medical applications of Nonlinear Time Reversal Acoustics

Abstract

Time Reversal Acoustic (TRA) focusing methods provide precise focusing and acoustic energy to chosen areas of the body, where various medical applications of these methods are under investigation. Here, we consider three prospective applications of the Nonlinear effects in TRA. Preliminary experiments for two of them were conducted several years ago, but were not published. A new third method combines TRA focusing with nonlinear acoustic imaging of ultrasonic contrast agents (UCA) for the following applications: 1. Nonlinear TRA method for blood pressure measurements directly in the blood stream. This method is based on the measurement of the second harmonic signal from an Ultrasonic Contrast Agent injected in the blood. 2. Nonlinear TRA for osteoporosis assessment. This is based on the concentration of acoustic energy of two signals with different frequencies in a small volume of bone. Measurements are made with a signal that sums the frequencies. Tests were conducted with a human calcanei bone sample. 3. Nonlinear TRA focusing to UCA for precise treatment of target areas and enhancement drug and gene delivery. This method is based on the reception of signals of nonlinear scattering from UCA and their frequency transformation and application of transferred signals for TRA focusing. Time Reversal Acoustic (TRA) focusing methods provide precise focusing and acoustic energy to chosen areas of the body, where various medical applications of these methods are under investigation. Here, we consider three prospective applications of the Nonlinear effects in TRA. Preliminary experiments for two of them were conducted several years ago, but were not published. A new third method combines TRA focusing with nonlinear acoustic imaging of ultrasonic contrast agents (UCA) for the following applications: 1. Nonlinear TRA method for blood pressure measurements directly in the blood stream. This method is based on the measurement of the second harmonic signal from an Ultrasonic Contrast Agent injected in the blood. 2. Nonlinear TRA for osteoporosis assessment. This is based on the concentration of acoustic energy of two signals with different frequencies in a small volume of bone. Measurements are made with a signal that sums the frequencies. Tests were conducted with a human calcanei bone sample. ...