Virtual array detector and inverse Radon transform used for photoacoustic imaging

A transducer with a fixed aperture is proposed as a virtual array detector to collect data. The transducer only needs to rotationally scan the sample 180 degrees. In the experiment, a Q-switched Nd: YAG laser operating at 532 nm was used as the light source, with a pulse width of 7 ns and a repetition frequency of 10 Hz. An unfocused transducer with a central frequency of 2.25 MHz and a diameter of 6 mm was applied to detecting photoacoustic signals. And the image was reconstructed by processing the received photoacoustic signals with the inverse Radon transform. An in vitro claw of a rat was used as the imaging object in the experiment and the data were obtained by rotating the transducer 180 degrees with a step of 2 degrees. The reconstructed image from the inverse Radon transform clearly displays the bones within the claw. The results indicate that the inverse Radon transform can be used for photoacoustic reconstruction and limited-view photoacoustic imaging is achieved with this method.