Enhanced Visualization of Biopsy Needle using a MEMS Actuator

Precise localization of needle tip is important for the biopsy. A mini actuator that radiates a low-intensity ultrasound burst was manufactured with MEMS technology. Interference between the radiated and diagnostic pulses was observed as bright lines in the sonography, from which the needle tip can be recognized with ease.

PZT wafer sputtered with electrodes on both sides was cut into 1 mm × 1 mm dies. The PZT die was bonded between two flexible electrodes patterned on liquid crystal polymer (LCP). The whole device was dip coated with a thin layer of PDMS as water proof treatment. 

The fundamental resonance is at 2.06 MHz, and the PDMS thin film has a damping effect on the transducer as seen by the reduced Q factors.

The visualization of the biopsy needle in a breast phantom was evaluated by an ultrasound imaging system. When the actuator was turned on, bright and clear lines in a conical shape appeared in the sonography B-mode imaging, from which the location of the actuator could be determined with ease.

For more information, please refer to:

[1] Zhiyuan Shen, Yufeng Zhou, Jianmin Miao, and Vu Kien Fong, “Enhanced visualization of fine needle under sonographic guidance using a MEMS actuator”, Sensors. 15, (2015), pp. 3107-3115.