RESUMO
Side-viewing hollow optical waveguides allow for minimally invasive endoscopy by concentrically guiding light and sound for photoacoustic generation and detection. Here, we characterize the side-viewing photoacoustic waveguide (PWG) endoscope by scanning 7.2⯵m diameter carbon fiber threads within phantom tissues and animal tissues. Photoacoustic signals are carried along the 5.5 and 10.0â¯cm length of the PWG with minimal attenuation. Thus, this technology enables 360°, deep-tissue photoacoustic imaging. Photoacoustic signals were identified up to 8.0â¯mm from the PWG imaging window in an optically clear medium. The outer diameter of this device is measured as just over 1.0â¯mm, with the potential to be further miniaturized due to its unique design. The PWG is an ideal candidate for a myriad of pre-clinical and clinical applications where typical photoacoustic endoscopy systems are impractical, due to their size. Presented here, is the first side-viewing photoacoustic waveguide endoscope.