title: Video-rate functional photoacoustic microscopy at depths.
abstract: We report the development of functional photoacoustic microscopy capable of video-rate high-resolution in vivo imaging in deep tissue. A lightweight photoacoustic probe is made of a single-element broadband ultrasound transducer, a compact photoacoustic beam combiner, and a bright-field light delivery system. Focused broadband ultrasound detection provides a 44-μm lateral resolution and a 28-μm axial resolution based on the envelope (a 15-μm axial resolution based on the raw RF signal). Due to the efficient bright-field light delivery, the system can image as deep as 4.8 mm in vivo using low excitation pulse energy (28 μJ per pulse, 0.35  mJ/cm² on the skin surface). The photoacoustic probe is mounted on a fast-scanning voice-coil scanner to acquire 40 two-dimensional (2-D) B-scan images per second over a 9-mm range. High-resolution anatomical imaging is demonstrated in the mouse ear and brain. Via fast dual-wavelength switching, oxygen dynamics of mouse cardio-vasculature is imaged in realtime as well.
authors.affiliation: Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, Campus Box 1097, One Brookings Drive, St. Louis, Missouri 63130-4899, USA.
authors.forename: Lidai
authors.initials: L
authors.lastname: Wang
authors.forename: Konstantin
authors.initials: K
authors.lastname: Maslov
authors.forename: Wenxin
authors.initials: W
authors.lastname: Xing
authors.forename: Alejandro
authors.initials: A
authors.lastname: Garcia-Uribe
authors.forename: Lihong V
authors.initials: LV
authors.lastname: Wang
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply; D003198:Computer Simulation; D004423:Ear / Q000098:blood supply / Q000000981:diagnostic imaging; D004453:Echoencephalography; D018496:Hyperoxia / Q000097:blood; D000860:Hypoxia / Q000097:blood; D051379:Mice; D008819:Mice, Nude; D033401:Microscopy, Acoustic / Q000295:instrumentation / Q000379:methods*; D018715:Microscopy, Video / Q000379:methods*; D055806:Microvessels; D009010:Monte Carlo Method; D061088:Photoacoustic Techniques / Q000295:instrumentation*