Two-Dimensional Temperature Imaging Using Diagnostic Ultrasound—Preliminary in Vitro Studies Using Phantom Materials

Temperature monitoring plays an important role during thermal therapy. Ultrasound (US) can be used to estimate the temperature, and the current approach is based on detection of the change in instantaneous frequency of reflected US signals along the US axial beam direction. In this thesis, a novel US-based temperature estimation technique has been proposed that improves on the current method by filtering the reflected US signals with Gaussian-weighted nth-order Hermite (GHn) polynomial function. In vitro experiments were conducted by slowly heating a series of tissue-mimicking phantom materials that were fabricated using hydrogel that were embedded with different-sized US scatterers. Overall, our US-based temperature mapping technique exhibited a 17.4% improvement in measurement accuracy compared to an established US imaging approach.