Induced modifications and temperature rises in the laser irradiation of whole biological specimens in vivo

Heating problems arising in the interaction between laser beams and biological targets are generally related to the observed direct biological effects. The speed of the carbonization and burning effects, as well as the interaction volume, depends for fixed wavelength and power levels on the parameters of the penetration depth, internal redistribution of light in the tissue, blood flow in the vessels, and mass transport due to the generated temperature gradient field. Then, from the point of view of theoretical models, the investigation to define the importance of the single contribution of the source terms in the heat transport equation is generally recognized as an interesting approach. We report in this paper experimental investigations concerning the temperature rise in the irradiation of whole in vivo biological specimens by visible laser beams and we compare them to theoretical models. Considerations relative to the thermal redistribution in the specimens are remarked. Biological modifications due both to direct or indirect thermal effects are also shown.