Acoustic resolution photoacoustic microscopy based on microelectromechanical systems scanner

Area of Science:

• Biomedical Imaging
• Optical Engineering
• Acoustic Imaging

Background:

• Photoacoustic microscopy (PAM) offers distinct optical resolution (OR)-PAM and acoustic resolution (AR)-PAM modalities.
• Microelectromechanical systems (MEMS) scanners have previously enabled high-speed OR-PAM.
• Limited imaging depth restricts OR-PAM's utility in preclinical and clinical settings.

Purpose of the Study:

• To demonstrate the application of a high-speed MEMS scanner for AR-PAM imaging.
• To evaluate the imaging performance and potential for miniaturization of MEMS-based AR-PAM.

Main Methods:

• Development of an AR-PAM system utilizing a high-speed MEMS scanner.
• Employing a 50 MHz transducer to achieve initial imaging parameters.
• Utilizing a higher frequency 75 MHz transducer to enhance resolution characteristics.

Main Results:

• A 50 MHz transducer yielded lateral resolution of 84 μm, axial resolution of 27 μm, and imaging depth of ~2.7 mm.
• A 75 MHz transducer improved resolution to 53 μm (lateral) and 18 μm (axial) with a reduced imaging depth of ~1.8 mm.
• A 2 × 2.5 mm² area was imaged in 3 seconds using the two-axis MEMS scanner.

Conclusions:

• High-speed MEMS scanners are suitable for AR-PAM, overcoming OR-PAM's depth limitations.
• This technology facilitates the development of compact, high-speed AR-PAM systems for deeper tissue visualization.
• The achieved resolutions and imaging speeds indicate significant potential for preclinical and clinical applications.