Sensitivity Enhanced Photoacoustic Imaging Using a High-Frequency PZT Transducer with an Integrated Front-End Amplifier

Abstract

Photoacoustic (PA) imaging is a hybrid imaging technique that can provide both structural and functional information of biological tissues. Due to limited permissible laser energy deposited on tissues, highly sensitive PA imaging is required. Here, we developed a 20 MHz lead zirconium titanate (PZT) transducer (1.5 mm × 3 mm) with front-end amplifier circuits for local signal processing to achieve sensitivity enhanced PA imaging. The electrical and acoustic performance was characterized. Experiments on phantoms and chicken breast tissue were conducted to validate the imaging performance. The fabricated prototype shows a bandwidth of 63% and achieves a noise equivalent pressure (NEP) of 0.24 mPa/√Hz and a receiving sensitivity of 62.1 μV/Pa at 20 MHz without degradation of the bandwidth. PA imaging of wire phantoms demonstrates that the prototype is capable of improving the detection sensitivity by 10 dB compared with the traditional transducer without integrated amplifier. In addition, in vitro experiments on chicken breast tissue show that structures could be imaged with enhanced contrast using the prototype and the imaging depth range was improved by 1 mm. These results demonstrate that the transducer with an integrated front-end amplifier enables highly sensitive PA imaging with improved penetration depth. The proposed method holds the potential for visualization of deep tissue structures and enhanced detection of weak physiological changes.

MEMS Ultrasound Transducers for Endoscopic Photoacoustic Imaging Applications

“…The measured center frequency and −6 dB fractional bandwidth are 13.1 MHz and 30%, respectively. Yang et al developed a 20 MHz pMUT (1.5 mm × 3 mm) based on PZT ceramic for PAI, showing a −6 dB bandwidth of 63% and a NEP of 0.24 at 20 MHz [ 96 ]. Both of them can be potentially applied in photoacoustic endoscopes.…”

Photoacoustic Phase Angle for Noninvasive Monitoring of Microcirculatory Change in Human Skin: A Preliminary Investigation

“…Among the state-of-the-art PA systems are the use of a transducer with integrated front end amplifier to simplify the complexity of its prior arts by eliminating optical receiver in the system [30]. The amplifier is to improve the detection sensitivity and to reduce noise.…”

Size Effect Study on High Frequency Transducers for Sensitivity Enhancement

“…The cable transmission loss is inevitable because the transducer has to be wired to the system, so minimizing the cable length is necessary. An alternative method is interfacing an amplifier closely to the transducer before connecting to the cable, high sensitivity is achieved while additional noise was reduce and signal amplification was provided [20]. This method can isolate the cable effect, which has great influence on the performance of high frequency transducer [12].…”