Selection of Excitation Signals and Acoustic Pressure Measurement for In-Vivo Studies with Ultrasound Array Research Platform II

Abstract

In recent years, the Ultrasound Group at the University of Leeds has developed an open platform (OP) known as Ultrasound Array Research Platform II (UARPII). The OP serves as a main component for researchers to test and implement new algorithms which is not feasible with the commercially available clinical scanners. In this paper, three types of excitation signals, the square pulse, 2-cycle sinusoid and linear frequency modulated chirps which are commonly employed in ultrasound imaging, were investigated for in-vivo experiments with the UARP II OP. The USA food and drug administration (FDA) provides strict guidelines that need to be followed when working with in-vivo medium. This is to ensure that the acoustic beam intensities do not cause any types of thermal damage and cavitation. The acoustic pressures produced by those excitation signals were measured with a needle hydrophone. The main three parameters of the excitation signals measured and calculated are the mechanical index (MI), spatial peak pulse average intensity (SPPA) and spatial peak temporal average intensity (SPTA). By considering advantages and disadvantages of all investigated excitation signals, the 2-cycle sinusoidal signal has been selected for all simulations and experiments with the in-vivo medium.