title: Non-planar pad-printed thick-film focused high-frequency ultrasonic transducers for imaging and therapeutic applications.
abstract: Pad-printed thick-film transducers have been shown to be an interesting alternative to lapped bulk piezoceramics, because the film is deposited with the required thickness, size, and geometry, thus avoiding any subsequent machining to achieve geometrical focusing. Their electromechanical properties are close to those of bulk ceramics with similar composition despite having a higher porosity. In this paper, padprinted high-frequency transducers based on a low-loss piezoceramic composition are designed and fabricated. High-porosity ceramic cylinders with a spherical top surface are used as the backing substrate. The transducers are characterized in view of imaging applications and their imaging capabilities are evaluated with phantoms containing spherical inclusions and in different biological tissues. In addition, the transducers are evaluated for their capability to produce high-acoustic intensities at frequencies around 20 MHz. High-intensity measurements, obtained with a calibrated hydrophone, show that transducer performance is promising for applications that would require the same device to be used for imaging and for therapy. Nevertheless, the transducer design can be improved, and simulation studies are performed to find a better compromise between low-power and high-power performance. The size, geometry, and constitutive materials of optimized configurations are proposed and their feasibility is discussed.
authors.affiliation: GREMAN, University of Tours, Tours, France. marc.lethiecq@univ-tours.fr
authors.forename: Marc
authors.initials: M
authors.lastname: Lethiecq
authors.forename: Rasmus
authors.initials: R
authors.lastname: Lou-Moeller
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Ketterling
authors.forename: Franck
authors.initials: F
authors.lastname: Levassort
authors.forename: Louis Pascal
authors.initials: LP
authors.lastname: Tran-Huu-Hue
authors.forename: Erwan
authors.initials: E
authors.lastname: Filoux
authors.forename: Ronald H
authors.initials: RH
authors.lastname: Silverman
authors.forename: Wanda W
authors.initials: WW
authors.lastname: Wolny
mesh_terms: D000818:Animals; D002516:Ceramics; D003198:Computer Simulation; D005123:Eye / Q000000981:diagnostic imaging; D007854:Lead; D019047:Phantoms, Imaging; D011817:Rabbits; D014025:Titanium; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*; D015040:Zirconium
chemical_list: C065536:lead titanate zirconate; D007854:Lead; D015040:Zirconium; D014025:Titanium