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

Effects of zinc oxide (ZnO) nanopowder dopant, on the acoustical and physical properties of silicone (Q) rubber have been investigated, in order to develop a low-acoustic attenuation, low sound velocity, and high-mechanical properties lens material for medical array probes. The ZnO-doped Q rubbers showed acoustic impedance (Z) = 1.29 to 1.46 times 10⁶ kg middot m^-2s^-1, acoustic attenuation = 0.54 to 0.74 dB. mm^-1 M.Hz^-1, and attenuation figure of merits (FOM) (attenuation times sound velocity) = 471 to 621 at 37degC. The attenuation FOM values for the Q rubber lens material are the lowest attenuation ever reported. The performance of 7.5 MHz linear array probe using the ZnO-doped Q rubber lens showed an increase of 3.5 dB in sensitivity compared to that of conventional Q rubber lens doped with SiO₂ powder. In addition, the material showed a high tear strength and a large elongation. The excellent mechanical properties of the ZnO-doped-Q rubber lens enable higher performance during longer operation in diagnosis compared with conventional Q rubber lens for medical array probe application.