Photoacoustic Generation Mechanisms and Measurement Systems for Biomedical Applications

Pulsed photoacoustic techniques for measurements in non-destructive evaluation (NDE) and for non-invasive characterization of tissues have been an in-creasingly attractive research area for over a decade. The physical principle underlying these techniques is based on the opto-thermal response of an absorbing media from pulsed laser sources. Resulting acous-tic waves are generated by the thermal expansion of absorbing volume within the irradiated material. Such waveforms contain valuable information about the optical properties of media, which can be uti-lized for diagnostic information such as the level of oxygenation in tissue or structure information within tissue. Several research groups have proposed medi-cal diagnostic systems based on pulsed photoacoustic methods. These include intra-arterial imaging and therapy, the monitoring of glucose level, the monitor-ing of cerebral blood oxygenation, the functional and structural imaging of brain, the monitoring the inter-face tissue layer within eye, and a diagnostic system for breast cancer. This review paper presents the ex-tensive review of the pulsed photoacoustic techniques for biomedical applications