BLOOD-CELL DAMAGE AFTER IN-VITRO IRRADIATION OF FRESH WHOLE-BLOOD WITH 630 NM LASER-LIGHT

A study on blood cell damage after irradiation of fresh whole blood wi th 630 nm laser light was carried out in vitro, Various fluence rates of laser light were used with and without cooling of blood. Damage to the blood was assessed by blood cell counts, osmotic fragility measure ments and examination of blood films, Exposure of a 1 mm blood layer t o 630 nm laser light without cooling led to changes in blood counts fi rst detected at fluence rates of 130 mW/cm(2). Changes in osmotic frag ility first became evident at 210 mW/cm(2). Increasing cell damage wit h increasing fluence rates was evident in blood films. Using the cooli ng device changes in whole blood after irradiation first occurred at a fluence rate of 293 mW/cm(2), Measurement of the fluence rates at whi ch cell damage begins is important in laser induced fluorescence diagn ostics and photodynamic therapy applications in blood or blood product s using photosensitizers. (C) 1998 Academic Press.