Confocal dual-frequency enhances the damaging effect of high-intensity focused ultrasound in tissue-mimicking phantom.

The volume of the lesions created by conventional single-frequency high-intensity focused ultrasound (HIFU) is small, which leads to long treatment duration in patients who are undergoing tumor ablation. In this study, the lesions induced by confocal dual-frequency HIFU in an optically transparent tissue-mimicking phantom were investigated and compared with the lesions created by conventional single-frequency HIFU. The results show that using different exposure times resulted in lesions of different sizes in both dual-frequency and single-frequency HIFU modes at the same spatially averaged intensity level (ISAL = 4900 W cm(-2)), but the lesion dimensions made in dual-frequency mode were significantly larger than those made in single-frequency mode.