ABSTRACT
Microwave-induced acoustic (thermoacoustic) tomography (TAT) has been developed to combine microwave contrast and ultrasonic resolution in a single hybrid modality. Even if the target has no ultrasonic contrast, TAT can detect the target if microwave contrast exists. Microwave contrast at the 3-GHz frequency is primarily related to water and ion concentrations. TAT was demonstrated to image thermal lesions and breast tumors. This chapter investigates the potential of TAT for monitoring high-intensity focused ultrasound (HIFU) therapy. HIFU has been used as an effective minimally invasive treatment for tumors deep in the body. To improve the clinical efficacy of HIFU therapy, much effort has been focused on developing effective imaging techniques for monitoring the treatment process. HIFU-induced lesions in porcine muscle were imaged with TAT. A single, spherically focused ultrasonic transducer operating at a central frequency of ~4 MHz was used to generate a HIFU field in fresh porcine muscle.
