title: Functional photoacoustic microscopy for high-resolution and noninvasive in vivo imaging.
abstract: Although optical absorption is strongly associated with the physiological status of biological tissue, existing high-resolution optical imaging modalities, including confocal microscopy, two-photon microscopy and optical coherence tomography, do not sense optical absorption directly. Furthermore, optical scattering prevents these methods from imaging deeper than approximately 1 mm below the tissue surface. Here we report functional photoacoustic microscopy (fPAM), which provides multiwavelength imaging of optical absorption and permits high spatial resolution beyond this depth limit with a ratio of maximum imaging depth to depth resolution greater than 100. Reflection mode, rather than orthogonal or transmission mode, is adopted because it is applicable to more anatomical sites than the others. fPAM is demonstrated with in vivo imaging of angiogenesis, melanoma, hemoglobin oxygen saturation (sO2) of single vessels in animals and total hemoglobin concentration in humans.
authors.affiliation: Optical Imaging Laboratory, Department of Biomedical Engineering, Texas A&M University, 3120 TAMU, College Station, Texas 77843-3120, USA.
authors.forename: Hao F
authors.initials: HF
authors.lastname: Zhang
authors.forename: Konstantin
authors.initials: K
authors.lastname: Maslov
authors.forename: George
authors.initials: G
authors.lastname: Stoica
authors.forename: Lihong V
authors.initials: LV
authors.lastname: Wang
mesh_terms: D019412:Anatomy, Cross-Sectional / Q000295:instrumentation*; D000818:Animals; D004867:Equipment Design; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D008545:Melanoma / Q000648:ultrastructure; D051379:Mice; D008819:Mice, Nude; D033401:Microscopy, Acoustic / Q000379:methods*; D014699:Venules / Q000648:ultrastructure