Characterization of a needle hydrophone array for acoustic feedback during ultrasound hyperthermia treatments

A prototype 16-element needle hydrophone array has been designed, fabricated, and characterized. The primary use of this array is to provide acoustic feedback during ultrasound hyperthermia treatments. This feedback is necessary to compensate phase array heating patterns for patient motion and tissue inhomogeneities in real time. The array consists of a polyvinylidene fluoride (PVDF) covered silicon substrate carrier which contains the signal electrodes of the individual acoustic sensors. Tests show that the array is sensitive to both pulsed and continuous ultrasound (943-kHz) excitation and can be used in tissue media. A complete description of the needle array, element cross-coupling measurements, beam profile measurements, calibration procedures, and sensitivity analyses in both water and tissue is presented