Fabrication and characterization of a 20 MHz microlinear phased array transducer for intervention guidance

This paper describes the design and fabrication of a miniature ultrasonic phased array transducer used for intervention guidance. Interventional procedures such as biopsy have been widely carried out in clinics for both diagnostic and therapeutic purposes of many different kinds of diseases, including cancer and cardiovascular disease. Due to its real-time imaging capability and non-radiating nature, ultrasound has been one of the common guiding tools for interventional procedures. However, currently the ultrasound probes are often placed at the body surface, which leads to several drawbacks including the limitations of image depth and quality. In this work, a miniature phased array transducer that can be placed adjacent to the intervention device has been developed. The array transducer comprised 48 elements and was placed in a 4-mm needle housing. The measured average center frequency and the bandwidth were around 18.5 MHz and 61% respectively. The measured axial and lateral image resolutions of the transducer were 80 μm and 210 μm respectively. The imaging capability of the transducer was evaluated by acquiring the B-mode images of a needle in a cow liver. The performance of the proposed phased array transducer demonstrates the feasibility of such an approach for interventional guidance.