Photoacoustic imaging utilizing excitation from a pulsed laser energy source, which takes advantage of high optical contrast and high acoustic resolution, is a high-contrast, high-resolution and noninvasive imaging method. In this paper, a modified filtered back-projection algorithm with velocity potential integration was used to reconstruct the photoacoustic image, and this method can solve the problem of the low contrast in the middle of photoacoustic image. The theory of photoacoustic signal generation was derived and the relationship between velocity potential and absorption distribution was also given. An Nd: YAG laser, operating at the wavelength of 532 nm with a full-width at high magnitude (FWHW) of 10 ns and a repetition of 15 Hz, was used in the experiment as the light source. A simulation sample was irradiated by the laser, and then the photoacoustic signal was generated. The photoacoustic signal was received by a needle hydrophone, which pointed to the center of the samples and controlled by a precision stepper motor to scan circularly around the sample, last the data was saved by the computer. The photoacoustic images of the sample were reconstructed without and with velocity potential integration respectively via modified filtered back-projection algorithm. The reconstruction profile and the quantitative evaluation were presented, and the reconstruction results show that this modified reconstruction algorithm can enhance image contrast and improve image quality greatly.

Date Published: 28 October 2009
PDF: 8 pages
Proc. SPIE 7519, Eighth International Conference on Photonics and Imaging in Biology and Medicine (PIBM 2009), 75190L (28 October 2009); doi: 10.1117/12.841448

Published in SPIE Proceedings Vol. 7519:
Eighth International Conference on Photonics and Imaging in Biology and Medicine (PIBM 2009)
Qingming Luo; Lihong V. Wang; Valery V. Tuchin; Pengcheng Li; Ling Fu, Editor(s)