Figure 1.

Design schema for the forward-firing deployable ultrasound applicator, consisting of a phased cylindrical transducer array situated at the distal end of a catheter and surrounded by a dual compartment balloon. (a) During device delivery and removal, the balloon would be in a collapsed state for an overall compact profile. (b) After placement at the target site, the balloon would deploy by filling the interior balloon compartment with water and the thin outer compartment with air, forming a reflective boundary directing energy forward. Appropriate phasing of the transducer elements permits focusing and steering in depth beyond the tip of the applicator, mimicking a larger aperture concentric-ring array.