Acoustic Field Measurement and Analysis for a Spherical Phased Array by PVDF Needle Hydrophone

High-intensity focused ultrasound (HIFU) with phased array is a hot topic in hyperthermia and its field characterization is important for the safety and efficiency of clinical treatment. This study analyzes the theoretical and the experimental results of the acoustic field generated by a 90-element ultrasonic spherical phased array. The spherical phased array with a central hole is operated at 1 MHz. The acoustic field distributions of the phased array are simulated using a pseudo inverse method performed by MATLAB. Meanwhile, in order to get the pressure distributions, a polyvinylidene fluoride (PVDF) needle hydrophone controlled by LabVIEW virtual oscillograph is employed to scan the acoustic filed. The measurement results are approximately consistent with simulation results and demonstrate the feasibility and validity of the measurement system.