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

Abstract

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. Difference frequency acoustic fields that exist in the confocal region of dual‐frequency HIFU may be the reason for the enlargement of the lesions' dimensions. The dual‐frequency HIFU mode may represent a new technique to improve the ablation efficiency of HIFU. The total time for the ablation of a tumor can be reduced, thus requiring less therapy time and reducing possible patient complications.

• HIFU
• ultrasound
• tissue‐mimicking phantom
• dual‐frequency
• lesion