Frequency Parametric Study for a HIFU Transducer Intended for Bone Tumor Treatment

Over the last year, bone tumor accounted leastwise than 1% of all new cancers diagnosis. The diagnosis is not usually opportune due to the few symptoms that patients present, and the options for treatment are generally invasive, like surgery or chemotherapy and radiotherapy, involved risk to the patient. In recent years, new therapies for treatment of bone tumors have being studied, such as high intensity focused ultrasound. This technology allows energy concentration at a specific point, named focus, which yields on a temperature increase in a short time. In this work, a parametric study of the acoustic propagation modeling in water of a spherical bowl transducer was evaluated in a frequency range from 1 to 10 MHz. The radiator geometry was established according to a commercial transducer with 4 MHz operating frequency. From the preliminary results, frequencies from 2 to 6 MHz were selected to analyze the acoustic propagation when cortical bone tissue with different thicknesses was added to the model. This study presented a shortening of focus for both different frequencies and bone thickness compared to the acoustic propagation of the transducer in water. The best results were frequencies from 3 to 5 MHz with bone thickness of 0.5 mm. Furthermore, the results gave an overview in the analysis of possible frequencies and bone thicknesses that could be used with more specific conditions to those described in this work.