| Full text | |
| Author(s): |
Baggio, Andre L.
;
Kamimura, Hermes A. S.
;
Henrique Lopes, J.
;
Carneiro, Adilton A. O.
;
Silva, Glauber T.
Total Authors: 5
|
| Document type: | Journal article |
| Source: | APPLIED ACOUSTICS; v. 126, p. 143-148, NOV 2017. |
| Web of Science Citations: | 2 |
| Abstract | |
In vibro-acoustography imaging systems, two ultrasound beams of distinct frequencies are employed to form an image of biological tissue at the difference-frequency. Three mechanisms contribute to the difference-frequency pressure, namely induced acoustic emission by a time-modulated radiation force, parametric array signal due to the superposition the beams along the propagation direction, and interaction of sound-with-sound effects. We analyze the strength of parametric array signal generated by a vibro-acoustography system composed of a two-element confocal transducer driven by two sinusoidal signals with center frequency 3.2 MHz. A 1-mm diameter tungsten sphere, placed at the transducer's focus, is used as the target object. We measure the difference-frequency pressure in water at room temperature with a calibrated hydrophone. The measurements are taken along the beam's axis in the farfield. In this configuration, the difference-frequency signal is mostly due to the parametric array phenomenon. Additionally, the acoustic emission and interaction of sound-with-sound signal levels are theoretically estimated. They are, respectively, 33 and 20 dB below the parametric array signal. (C) 2017 Elsevier Ltd. All rights reserved. (AU) | |
| FAPESP's process: | 11/10809-6 - Sonothrombolysis by focused and modulated acoustic radiation force using double beam |
| Grantee: | Hermes Arytto Salles Kamimura |
| Support type: | Scholarships in Brazil - Doctorate |