Photoacoustic microscopy: principles and biomedical applications

Abstract

Photoacoustic microscopy (PAM) has become an increasingly popular technology for biomedical applications, providing anatomical, functional, and molecular information. In this concise review, we first introduce the basic principles and typical system designs of PAM, including optical-resolution PAM and acoustic-resolution PAM. The major imaging characteristics of PAM, i.e. spatial resolutions, penetration depth, and scanning approach are discussed in detail. Then, we introduce the major biomedical applications of PAM, including anatomical imaging across scales from cellular level to organismal level, label-free functional imaging using endogenous biomolecules, and molecular imaging using exogenous contrast agents. Lastly, we discuss the technical and engineering challenges of PAM in the translation to potential clinical impacts.

Feasibility Study of Precise Balloon Catheter Tracking and Visualization with Fast Photoacoustic Microscopy

“…Finally, two or three-dimensional images can be obtained via reconstruction algorithms. Thanks to less scattering of ultrasound in biological tissue, PAI can achieve deep tissue imaging while maintaining ultrasonic resolution [ 20 , 21 , 22 , 23 , 24 ]. Furthermore, depending on aiming applications, PAI can provide multiscale images from several nanometers to several centimeters selectively by controlling systemic specifications between optical and ultrasonic [ 25 ].…”

Photoacoustic Imaging in Tissue Engineering and Regenerative Medicine

“…PAM typically utilizes a confocal configuration by having overlapped foci of both the optical excitation and ultrasonic detection to optimize its sensitivity and resolution. 36 As the time-of-flight information of the PA signal provides the axial resolution, each focused laser beam position produces a depth-resolved one-dimension (line) image into the tissue without mechanical scanning. Thus, a 2D transverse scanning of the laser beam (together with the US receiver) generates a 3D image.…”

“…PAI has been used as a noninvasive measure to track stem cells following implantation. To date, various contrast agents have been investigated for stem cell tracking, including dyes, 36,140 reporter genes, 141 fluorescent probes, 142 and NP. 143,144 Recently, bone mesenchymal stem cells (BMSCs) were investigated as a treatment in a mice brain injury model and were labeled with Prussian blue particles to generate PA image contrast.…”

“…143,144 Recently, bone mesenchymal stem cells (BMSCs) were investigated as a treatment in a mice brain injury model and were labeled with Prussian blue particles to generate PA image contrast. 36 PA tomography images following BMSC treatment provided pathophysiological status of brain injury, vascularization information, and recovery process. PA images indicated injury location and change in the bleeding area starting at 3 min following injury.…”

Multimodal photoacoustic imaging: systems, applications, and agents

“…The fifth paper entitled ''Multimodal Intravascular Photoacoustic and Ultrasound Imaging'' by Li et al [13] addresses the recent advances on the multimodal intravascular PA/US catheters to morphologically and chemically image atherosclerotic plaques in coronary arteries. The sixth paper entitled ''Photoacoustic Microscopy: Principles and Biomedical Applications'' by Liu et al [14] introduces the fundamental principles and system configurations of PA microscopy and preclinical/clinical applications of the systems. PA microscopy has become a premier tool in biomedical research, providing structural, physiological, and molecular signals of diseased tissues.…”