Optoacoustic imaging using a three-dimensional reconstruction algorithm

A novel three-dimensional (3-D) computational algorithm to reconstruct 3-D optoacoustic images from two-dimensional (2-D) pressure distributions generated at the sample surface is presented. The 2-D pressure distributions were measured as images at different delay times after the excitation laser pulse. The pressure images were captured with a gated CCD camera as the local pressure induces intensity changes of a reflected probe beam at the surface of the irradiated sample. The illumination time was 10 ns and the resolution of the surface pressure image was 20 mum. The reconstruction algorithm is based on the decomposition into plane waves. The algorithm was tested in the back projection of simulated pressure transients of three sources, and applied to different biological systems. Furthermore the algorithm was compared with the time of flight back projection algorithm. Optoacoustic images with a depth resolution of 15 mum and a lateral resolution of 100 mum are presented.