Designing a multi-element array transducer for abdominal boiling histotripsy applications

Abstract

The boiling histotripsy (BH) method to mechanically fractionate tissue using high intensity focused ultrasound relies on the presence of high amplitude shocks. Recently, a method of determining single-element transducer parameters to achieve desired shock amplitudes at the focus was developed. It was shown that the transducer F-number is the main parameter that determines the focal pressure level at which fully developed shocks form. Here, a 256-element HIFU array transducer of 1.5 МHz frequency was designed for abdominal BH applications using the proposed method. An opening was included at the center of the transducer to fit an ultrasound imaging probe and a compact 16-arm spiral layout of uniformly sized elements was chosen for maximizing the transducer power output. The F-number of the array and the diameter of its elements were determined to satisfy technical limitations on the intensity level at the array elements as well as the required shock amplitudes of 90-100 MPa at the focus assuming 9 dB atten...