Miniature Transducer Using PNN-PZT-Based Ceramic for Intravascular Ultrasound

In this work, the development and performance evaluation of a high-frequency miniature ultrasonic transducer based on a Pb(Ni
_1/3
Nb
_2/3
)O
₃
-Pb(Zr
_0.3
Ti
_0.7
)O
₃
(PNN-PZT-based) ceramic for intravascular imaging application are reported. The fabricated PNN-PZT-based ceramic possesses ultrahigh relative clamped dielectric permittivity (ε
^s
/ε
₀
= 3409 and high electromechanical coupling capability (k
_t
= 0.60). A 42-MHz high-frequency side-looking ultrasonic transducer probe using the PNN-PZT-based ceramic with a miniature aperture of 0.33 mm was designed and fabricated, which exhibited a wide -6-dB bandwidth of 79% and an insertion loss of -19.6 dB. High spatial resolution, including the axial resolution of 36 cm and the lateral resolution of 141μm, was determined by imaging a 13-μm tungsten wire phantom. Ex vivo intravascular ultrasound (IVUS) imaging of a porcine coronary artery was performed to show the imaging capability of the miniature transducer. The results demonstrated the great potential of the PNN-PZT-based ceramic for high-resolution miniature transducers application.