Professors Chulhong Kim and Geunbae Lim Develop High-speed Optical Resolution Photoacoustic Microscopy
A team comprised of Profs. Chulhong Kim and Geunbae Lim, Jin Young Kim, Changho Lee, and Kyungjin Park, developed a high-speed optical-resolution photoacoustic microscopy (OR-PAM) system using 2-axis waterproofing MEMS scanner, successfully monitored the flow of carbon particles in-vitro, and imaged microvascular networks of the mouse ear in vivo. Their research findings were published in Scientific Reports journal. Photoacoustic imaging technique is a hybrid biomedical imaging technique that combines the merits of ultrasonic and optical imaging modalities. When a pulsed light illuminates and spreads into biological tissues, targeted biomolecules absorb light, and finally acoustic waves are created via thermoelastic expansion. This process is called as photoacoustic (PA) effect. Finally, a conventional ultrasonic transducer detects the generated acoustic waves and volumetric PA images can be obtained. Particularly, OR-PAM can noninvasively provide label-free microscopic images such as oxy and deoxy-hemoglobin, melanin, and DNA/RNA in cell nuclei. Thanks to the key advantages, OR-PAM has been widely used to study oncology, neuroscience, label-free histology, dermatology, ophthalmology, and cardiology. Although OR-PAM is regarded as a promising high-resolution microscopic technique, there is a pressing need to develop a compact, fast, and cost-effective OR-PAM system while maintaining high SNRs for wide spread preclinical and clinical applications.
The team presents a new type of MEMS scanner, which works perfectly in water and co-axially reflects both ultrasound and laser beam to scan a 2D plane. Thus, high SNRs were achieved without sacrificing the imaging speed. The small size and simple operation of the MEMS scanner can greatly reduce the complexity of the OR-PAM system. By using this 2-axis MEMS scanner, the team expects to build a further smaller footprint of OR-PAM for endoscopy or laparoscopy.
The study is a step forward for cancer research by providing high-resolution video and will enable real-time biopsy in the operating room, providing more accurate results that are expected to significantly help provide health care services.