A Novel Optical Oximeter via Absorption Spectra- Based CO2 Laser Photothermal Effects

Spectroscopic and histological study of CO2 laser interaction with rats tissues were carried out. We
detected for the first time the changes in optical absorption spectra of rat's tissues with selective CO2
laser optical densities ranging from 20.64 to 34.40W/cm2. The laser exposed tissues show higher
absorbance in hemoglobin than that for the unexposed tissue. Using the same laser and same optical
densities, the absorption spectra of fresh blood were measured. Much intense peaks of hemoglobin in
the exposed fresh blood than that for the corresponding peaks for the tissue were detected. A scheme
based on recent experimental findings is proposed for explanation of this novel phenomenon. The
histological study shows thermal damage of blood vessels localized at the dermis layer. At high laser
optical densities a vessel rupture with hemorrhage were occurred. The results indicate a pronounced
modification of skin absorption properties by laser irradiation. Such an effect is due to thermally
induced biophysical and biochemical processes inside the highly heterogeneous tissue structure. A
clinical oximeter can be optimized by using CO2 laser Photothermal effects This device plays an
important role during COVID-19 pandemic.