Recent advances toward clinical applications of photoacoustic microscopy: a review

Photoacoustic imaging (PAI) is an emerging technology that has been dramatically developed in the last decade. PAI, a combination of optical illumination and ultrasound detection, allows us to achieve fine resolution and obtain fruitful information of endogenous and exogenous chromophores. Among PAI imaging techniques, photoacoustic computed tomography (PACT) has been extensively used in human studies due to its deep tissue penetration (several centimeters). Alternatively, photoacoustic microscopy (PAM) offers higher resolution at the expense of penetration depth, which can also be advantageous in clinics. Recently, there has been increasing attention and studies on PAM of human tissues. In this paper, we will review principles of PAM and its applications to human tissues, including the breast tissue, carotid atheroma tissue, eye, gastrointestinal tissue, ovarian tissue and tooth ex vivo as well as the oral cavity and dermatological tissue in vivo. The paper is closed with the outlook regarding the potential applications of PAM in clinics.