A Miniaturized Multidirectional Stacking Ultrasound Transducer for Endo-bronchoscopy Lung Nodule Ablation

Lung cancer is the leading cause of cancer death worldwide with estimated over 230,000 being diagnosed in USA annually. There is a growing interest in minimally invasive treatment for early-stage lung cancer. However, currently available endoscopic ablative techniques, such as radiofrequency, microwave, and cryotherapy, have practical design or safety-related limitations. To overcome these drawbacks, ultrasound ablation is a promising technique due to the solid nature of tumors and the reflective surrounding aerated lung tissue, as well as the ability to focus acoustic energy with multiple transducer arrays for improved safety. Yet, existing ultrasound endoscopic arrays are limited by insufficient power output due to their small dimensions. Here we designed and fabricated a miniaturized, multidirectional ultrasound transducer with two-layer stacks that can be used in modern bronchoscopic procedures to target peripheral pulmonary lesions. The multi-directional transducer is expected to have an overall dimension of 2.2 × 2.0 × 5.2 mm ³ with a capability of temperature rise to over 60 °C in 2 min for tissue ablation.