Photoacoustic Examination of Red Blood Cell Suspensions

This study aims to investigate the role of red blood cell (RBC) concentration on photoacoustics (PAs). The time dependent PA signals from a collection of RBCs were simulated using a recently developed theoretical model. This model assumes each RBC as a fluid sphere and the PA signals from many cells are generated by adding the contributions from the individual cells. A Monte Carlo technique was implemented to generate the random locations of RBCs within a 2D simulation volume (200×200 μm²) mimicking a tissue realization. The PA signals were simulated for the 355 and 532 nm irradiating optical radiations. Our simulation results demonstrated that PA signal amplitude increased monotonically with RBC concentration for both input radiations and exhibited similar trends with those of experiments. The experiments were conducted with porcine RBCs suspended in saline water. A Nd:YAG laser system was used to provide the desired radiation and the detection of acoustic signals were made by a needle hydrophone. Good agreement between theoretical and experimental results confirms the validity of the theoretical model.