title: 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 20MHz 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 20MHz 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 10mm, and exhibited an axial resolution of 66μm and a lateral resolution of 520μm. 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.
authors.affiliation: Dept. of Anesthesiology, Keck School of Medicine, University of Southern California, United States. raphael.david92@gmail.com
authors.forename: David T
authors.initials: DT
authors.lastname: Raphael
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: Jinhyoung
authors.initials: J
authors.lastname: Park
authors.forename: Ruimin
authors.initials: R
authors.lastname: Chen
authors.forename: Hamid
authors.initials: H
authors.lastname: Chabok
authors.forename: Arthur
authors.initials: A
authors.lastname: Barukh
authors.forename: Qifa
authors.initials: Q
authors.lastname: Zhou
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Elgazery
authors.forename: K Kirk
authors.initials: KK
authors.lastname: Shung
mesh_terms: D000818:Animals; D002417:Cattle; D005123:Eye / Q000000981:diagnostic imaging; D066298:In Vitro Techniques; D019047:Phantoms, Imaging; D014465:Ultrasonics; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods