Affiliations: Department of Physics and Engineering, University of
Central Oklahoma, 100 North University Drive, Edmond, OK 73034, USA | Department of Veterinary Clinical Sciences, College of
Veterinary Medicine and Center for Laser Research, Oklahoma State University,
Stillwater, OK 74078, USA | Center for Bioengineering and School of Electrical and
Computer Engineering, University of Oklahoma, Norman, OK 73019, USA | Wound Healing of Oklahoma, 3945 North Walnut Street,
OK City, OK 73105, USA
Note: [] Corresponding author: Wei R. Chen, Ph.D., Professor and
Director, Biomedical Engineering Program, Department of Physics and
Engineering, University of Central Oklahoma, 100 North University Drive,
Edmond, OK 73034, USA. Tel.: +1 405 974 5198; Fax: +1 405 974 3812; E-mail:
wchen@ucok.edu
Abstract: The impact of laser photothermal interactions on tissue damage and
recovery was studied. A Ho:YAG laser (2.12 μm) was used
to irradiate rabbit skin with different operating parameters. The thermal
effect on the skin tissue was examined by measurement of laser-induced lesions
and by tissue histology. The lesion size on the surface, the photocoagulation
depth and the thermal damage depth were recorded as functions of irradiation
parameters. The lesion width and the photocoagulation depth increased with the
beam energy while the area of thermal damage remained relatively unchanged. At
the fluence levels of 453 J/cm^{2} and
680 J/cm^{2}, laser energy damaged the dermis all the way to
the panniculus carnosa, resulting in total dermal collagen photocoagulation,
but with little damage to the muscle. Post-treatment histological observation
showed a rapid tissue healing and skin regeneration process. The thermal damage
on rabbit skin began recovery within a short period and new epithelial growth
was clearly seen at day 3. By 7 days, most of the photocoagulated zone was
separated from the main body and was replaced by a new layer of epithelium.
