A Photoacoustic Tomography System Based on a Double-Ring Sensor with a Narrow Angular Aperture

A photoacoustic tomography system is developed by using a double-ring sensor featuring a narrow angular aperture. An angular aperture of 2.0 degree can be obtained with this sensor, which improves the spatial resolution of the sensor in scanning direction. In this sensor a fiber for illumination of the sample is integrated, which enables reflection-mode detection of ultrasonic waves. These give the ability to make A-scans of the tissue on a line in depth. Scanning over the surface of the tissue, a photoacoustic tomography can be obtained in a manner analogous to the ultrasound B-can mode. The system is demonstrated with phantom samples, the reconstructed images agree well with the structures of the samples.