Review of pMUTs for medical imaging: towards high frequency arrays

Abstract

pMUT (piezoelectric Micromachined Ultrasound Transducer) devices are an alternative that can overcome the limitations associated with conventional ultrasound transducers. pMUT’s are reported for many applications such as range-finding, biometrics, and ultrasound imaging. However, pulse-echo measurements from fabricated pMUT devices/arrays are not commonly reported in literature, a reason being lack of desirable performance either in transmit or receive mode of operation. There is also limited information about the design, fabrication and characterization of 2D-pMUT-arrays operating at high frequencies (>15 MHz) in water medium. In this paper we review ‘state-of-the-art’ for pMUT-array based medical ultrasound imaging, with a focus on their pulse-echo imaging capability. Over the next 3-5 years, we expect further improvement in piezoelectric thin film deposition techniques, on-chip integration of pre-amplification circuits and further miniaturization of pMUT devices, thus paving the way for development of pMUT-array based high frequency medical imaging systems.

A General-Purpose Non-invasive Neurotechnology Research Platform

“…Shaded areas indicate the standard error. As expected from the recording/reference locations on the forehead and consistent with the findings in Schalk et al (2023), the responses are smaller in amplitude and visually different than those measured with more common montages (e.g., Cz referenced to the earlobe). At the same time, they clearly detect EEG responses to visual stimulation, and they are different for oddball and standard stimulation.…”

“…It is almost certain that such (and other) measurements cannot be accomplished using sensors that are placed in a completely different location such as on the head. Likewise, optimization of practicality almost certainly requires placing electrodes outside the hair (e.g., on the forehead or around/inside the ear), but these locations will not provide optimal access to EEG signals that are typically detected in more central locations (Schalk et al, 2023).…”