Low acoustic attenuation silicone rubber lens for medical ultrasonic array probe

Abstract

Effects of heavy density (rho = 9.2 x 10(3) kg/m(3)) Yb(2)O(3) fine dopant (16 nm in diameter) on the acoustic properties of a high-temperature-vulcanization (HTV) silicone rubber have been investigated, to develop a new acoustic lens material with a low acoustic attenuation (alpha) for the medical array probe application. The HTV silicone rubber has advantages in that it shows a lower alpha than that of a room-temperature-vulcanization (RTV) silicone rubber and it can be mixed by applying shear stress, using roll-milling equipment. Roll-milling time dependence of the HTV silicone rubber indicates that the alpha is closely affected by the dispersion of nanopowders in the rubber matrix. The 8 vol% Yb(2)O(3)-doped HTV silicone rubber mixed for 30 min showed the lowest alpha of 0.73 dB/mm MHz with an acoustic impedance [AI = sound speed (c) x density (rho)] of 1.43 x 10(6) kg/m(2)s at 37 degrees C. Moreover, simulation results reveal that a 5 MHz linear probe using the HTV silicone rubber doped with Yb(2)O(3) powder showed relative sensitivity around 2.6 to 3.0 dB higher than a probe using RTV silicone rubber doped with Yb(2)O(3) powder or SiO2-doped conventional silicone rubber for the ultrasonic medical application.

Low-acoustic attenuation and high-mechanical strength silicone rubber lens doped with ZnO nanopowder for medical ultrasonic array probe

“…The Z increases as ZnO content increase and reached to Z = 1.46 × 10 6 kg/m 2 s when 15 vol% of ZnO was added. The attenuation increased monotonously as ZnO content increased, but, the values are smaller than those of Yb 2 O 3 -doped Q rubber reported previously [9]. α -FOMs obtained were the lowest values so far reported for acoustic lens Q rubber material with Z = 1.29 to 1.46 × 10 6 kg/m 2 s. And the attenuation FOMs are smaller than those for 8 to16 nm Yb 2 O 3 -doped HTV Q rubber.…”

“…The dopant content was varied to become the density of the Q rubber between 1.55 and 1.75 × 10 3 kg/m 3 , in order to obtain the Q rubber with the Z of around 1.3 to 1.5 × 10 6 kg/m 2 s. Table II shows ZnO-, Yb 2 O 3 -and SiO 2 -doped HTV Q rubber samples manufactured for the study. The detail manufacturing process and measurement methods are reported in previous papers [6][7][8][9]. …”

“…The authors have reported the acoustic properties of roomtemperature vulcanization (RTV) and high-temperature vulcanization (HTV) Q rubbers doped with 8 to 2000 nm Pt and Yb 2 O 3 powder [3][4][5][6][7][8][9]. These Q rubbers not only have low attenuation but also low sound velocity, which is very important in the manufacture of thinner acoustic lens [6].…”

Ultrasonic transducers for medical diagnostic imaging

“…The acoustic lens protects the ultrasonic transducer from exterior damage, and focuses the ultrasound beam onto a specified point based on Snell's law [13]. Materials with low attenuation constants are preferred to reduce the loss of ultrasound energy inside the lens [14,15]. Typical acoustic lenses are made of rubber materials for comfortable contact between the transducer and patients.…”

Full elastic characterization of absorptive rubber using laser excited guided ultrasonic waves

“…Rubber is being widely used to solve environmental problems caused by structural vibration and sound radiation [1][2][3][4][5] because of its high attenuation. For the very same reason, it is very difficult to characterize the dynamic properties of rubber materials, thus slowing down the improvement and tuning of the rubber composition in the material development process, in view of particular applications.…”