Endoscopic photoacoustic microscopy

We present a concept and system implementation for endoscopic photoacoustic microscopy that enables minimally invasive diagnosis of internal organs. The system incorporates an in-house made single element ultrasonic transducer for photoacoustic signal detection and an optical fiber for light delivery into a tubular probe with a mechanical scanning unit. The implemented probe size for the distal end is 4.2 mm in diameter and 48 mm in length. We evaluated the system's performance by imaging a carbon fiber in clear and turbid media. We also demonstrated its ability to image actual biological tissues and its endoscopic applicability, by imaging abdominal surfaces and a large intestinal tract of a rat ex vivo. This study shows the system's potential for in vivo optical biopsy of tissue abnormalities, such as tumors, developed in internal organs