Simulating insertion-based measurement of phantom attenuation and membrane transmission loss

Abstract

Attenuation of reference phantoms that are used in quantitative ultrasound applications must be accurately measured. In this regard, we recently proposed an insertion-based planar reflection technique to simultaneously estimate membrane transmission loss and phantom attenuation. Simulating the measurement procedure can assist with validating and improving the methodology and gauge its accuracy and precision by carefully controlling the simulation's setup parameters. For simulation, a pulse echo setup with a single element transducer immersed in water was implemented in k-Wave. First, a reference plane with known acoustic properties is positioned at the focus, yielding the reference echo that models transducer diffraction and frequency response. Next, a phantom covered by a thin layer of acoustic windowing membrane is inserted between the transducer and reference plane, yielding the insertion echo that captures the phantom attenuation and membrane transmission loss. Finally, the phantom top surface, lined with the membrane, is positioned at the focus, thereby yielding the surface echo that captures the membrane reflectivity. Spectral analysis of the three echoes estimates the membrane transmission-loss-corrected phantom attenuation. Preliminary simulation of a phantom with predefined attenuation coefficient of 0.6–0.9 dB/cm MHz yielded a root mean square error of 0.06 dB/cm MHz over 3–5 MHz. [NIH Support: R01CA226528, R01DK106419, and R01HD089935.]