Modeling-based design and assessment of an acousto-optic guided high-intensity focused ultrasound system

摘要

Real-time acousto-optic (AO) sensing has been shown to non-invasively detect changes in ex vivo tissueoptical properties during high-intensity focused ultrasound (HIFU) exposures. The technique is particularly appropriatefor monitoring non-cavitating lesions that offer minimal acoustic contrast. In this study, a numerical model ispresented for an AO-guided HIFU system with an illumination wavelength of 1064 nm and an acoustic frequency of1.1 MHz. To confirm the model’s accuracy, it is compared to previously published experimental data gathered duringAO-guided HIFU in chicken breast. The model is used to determine an optimal design for an AO-guided HIFU system,to assess its robustness, and to predict its efficacy for the ablation of large volumes. It was found that a throughtransmission geometry results in the best performance, and an optical wavelength around 800 nm was optimal as itprovided sufficient contrast with low absorption. Finally, it was shown that the strategy employed while treating largevolumes with AO guidance has a major impact on the resulting necrotic volume and symmetry.