Deployable tessellated transducer array for ultrasound focusing and bio-heat generation in a multilayer environment

High intensity focused ultrasound (HIFU) has great potential to thermally ablate diseased tissues with minimal invasion. Yet, HIFU practice has limited cancer treatment potential since the absorption, diffusion, and reflection of ultrasound prevent HIFU from penetrating the body to deep and concealed diseased tissue. To explore a vision of deployable HIFU transducers, this research introduces an origami-inspired concept wherein a deployable tessellated acoustic array is employed to reduce the distance between the HIFU transducer and diseased tissues. A flat-foldable HIFU transducer array is considered, such that the compact shape is used to pass through the human body and then deployed into the operational form for treatment. Here a theoretical framework is developed to study the focusing and thermal heating capabilities of the tessellated array in a multilayer environment. It is observed that the wavefield and thermal elevation realized by the foldable array are functionally similar to those of an ideal arc-shaped transducer. Folding patterns that permit adequate curvature and high quality factor, and that balance slenderness and conformability are found to be beneficial for an ultrasound focusing practice. The efficacy of the analytical predictions are verified through direct numerical simulations. All together, the results encourage attention to foldable array concepts as potential means to advance in-vivo HIFU-based procedures.