Influence of light irradiation modalities on light distribution in human whole blood

摘要

To compare the differences of the light distributions in blood with different light irradiation modalities; Monte Carlo simulation was applied. The light distribution of He-Ne laser (632.8nm) in human whole blood was simulated. The diameter of the optic fiber used was 400μm. We referred to the work done by other researchers to determine tissue optical parameters of blood. For the same output laser power of 5mW; our results showed that the highest power density could be more than 6000mW/cm2 using flat end optic fiber. But when using optical fiber coupled with cylindrical light diffuser (the length for light emission =3mm); the highest power density was less than 210mW/cm2. Increasing the length of light emission could further reduce the highest power density. In summary; the optical fiber coupled with cylindrical light diffuser is a good modality for in vivo light irradiation in whole blood; which can decrease the light intensity and make it more uniformed distributed in blood. It is of great importance to choose the suitable light emission length of optic fiber coupled with cylindrical light diffuser for clinical applications.