Detection of HIFU lesions by optical coherence tomography

Abstract

The use of high-intensity focused ultrasound (HIFU) to induce irreversible changes in tissue due to heating is well established. We have shown that changes in tissue optical properties (scattering and absorption coefficients) could be used as a proxy to improve sensing and imaging of HIFU lesion formation, as an alternative to conventional methods such as thermometry. Optical coherence tomography (OCT) is a non-invasive optical imaging method which relies on low-coherence interferometry to determine the depth of individual scattering centres within the tissue. Previous studies have demonstrated that OCT signals are sensitive to morphological changes in heated tissue, likely due to denaturation of proteins concomitant with formation of crosslinked structures. The goal of this study was to assess the use of OCT for sensing and imaging HIFU lesions. We demonstrate the feasibility of imaging near-surface lesions in ex vivo chicken breast tissue exposed to HIFU. This technique has potential for detecting changes in optical properties corresponding to the progression of surface lesion formation which are antecedents of skin burn during HIFU exposures, thereby increasing safety and reducing treatment times.