20 MHz forward-imaging single-element beam steering with an internal rotating variable-angle reflecting surface: Wire phantom and ex vivo pilot study

Abstract

Feasibility is demonstrated for a forward-imaging beam steering system involving a single-element 20 MHz angled-face acoustic transducer combined with an internal rotating variable-angle reflecting surface (VARS). Rotation of the VARS structure, for a fixed position of the transducer, generates a 2-D angular sector scan. If these VARS revolutions were to be accompanied by successive rotations of the single-element transducer, 3-D imaging would be achieved. In the design of this device, a single-element 20 MHz PMN-PT press-focused angled-face transducer is focused on the circle of midpoints of a micro-machined VARS within the distal end of an endoscope. The 2-D imaging system was tested in water bath experiments with phantom wire structures at a depth of 10 mm, and exhibited an axial resolution of 66 μm and a lateral resolution of 520 μm. Chirp coded excitation was used to enhance the signal-to-noise ratio, and to increase the depth of penetration. Images of an ex vivo cow eye were obtained. This VARS-based approach offers a novel forward-looking beam-steering method, which could be useful in intra-cavity imaging.

A 2-D Ultrasound Transducer With Front-End ASIC and Low Cable Count for 3-D Forward-Looking Intravascular Imaging: Performance and Characterization

“…In the first case, 2-D FL scans can be achieved, whereas with the second approach a cone of visualization is created ahead of the catheter tip. Other approaches for single-element FL imaging include a rotating reflecting surface [14] that reflect the ultrasound beam with different angles ahead of the catheter tip and a mechanically wobbling transducer with shape-memory alloys [15]. These approaches require the need to develop complex mechanisms, making the whole catheter bulky.…”

Structural Design and Experimental Studies of Resonant Fiber Optic Scanner Driven by Co-Fired Multilayer Piezoelectric Ceramics

“…According to the driving method, optical scanners are primarily classified into mechanical, galvanometric, electronic, micro-electro–mechanical systems (MEMS), piezoelectric systems, etc. [ 1 , 2 , 3 , 4 , 5 ]. Currently, the most used mechanical optical scanners cannot easily meet the requirements of large angles, low errors, or high-speed scanning.…”

Piezoelectric bimorph-driven ultrasound scanner for high frequency ultrasound imaging

“…In this system, the ultrasound transducer remains stationary, while the acoustic path is quickly steered by a water-proofed microelectromechanical (MEMS) scanner, enabling real-time ultrasound imaging. Raphael et al [11] achieved ex vivo cow eye imaging using a single-piece 20 MHz PMN-PT pressurefocused angular surface transducer, which was focused on the midpoint circle of the micromachined VARS at the distal end of the endoscope. This VARS-based approach provides a novel forward-looking beam-steering method that could be useful in intra-cavity imaging.…”