Photohemolysis of erythrocytes by He-Ne laser irradiation: the effect of power density.

The effects of He-Ne laser irradiation on erythrocyte hemolysis were studied. Erythrocytes are prone to be easily damaged with hemolysis under laser irradiation. It was found that the power density (PD) of laser irradiation, but not the total irradiation power, is the crucial parameter for the hemolysis. Under irradiation with a PD of 5.41 mW/microm(2), erythrocytes were photohemolyzed within a few seconds, while at a PD of 0.52 mW/microm(2) the average tolerance duration (TD; from the start of irradiation to hemolysis) of erythrocytes was 110 s. The TDs of erythrocytes were also individual erythrocyte-dependent, which may be due to their different ages. The average TDs of erythrocyte samples from different donors were different, reflecting individual variations.