Recent advances in photoacoustic endoscopy

Figure 2 Three major implementations of photoacoustic tomography, with representative in vivo images. A: Optical-resolution photoacoustic microscopy and an image of hemoglobin oxygen saturation (SO₂) in a mouse ear; B: Circular-array photoacoustic computed tomography and an image of cerebral hemodynamic changes, ∆[hemoglobin], in response to one-sided whisker stimulation in a rat; C: Photoacoustic endoscopy and an image of a rabbit esophagus and adjacent internal organs, including the trachea and lung. Reproduced with permission from Wang et al[5]. SO₂: Oxygen saturation; UST: Ultrasonic transducer.