Thermal damage due to incidental continuous CO2 laser irradiation on human skin

The use of laser instruments in almost every aspect of technology may lead to sudden exposing of human skin to laser radiation, especially with an invisible laser, such as continuous CO2 laser, causing harmful thermal damage to the exposed area. This phenomena is studied in this work where the size of thermal damage is obtained using a well-known thermal dose equation which requires the transient temperature distributions obtained from finite element solution of the axi-symmetric heat equation. In this work a numerical simulation of these processes is applied indicating that the size of thermal damage zone inside human tissue seems to increase as power increases even if the exposing time is reduced, whereas the shape of thermally damage zone extends laterally much more than in-depth due to the effect of absorption coefficient and perfusion rate of skin tissue. Finally, this work may establish the concept of numerical investigation of an incidental laser hazard on human skin.

Download Full-text

Threshold of permanent cornea thermal damage due to incidental continuous wave CO2 laser irradiation

Thermal Science ◽

10.2298/tsci1002459t ◽

2010 ◽

Vol 14 (2) ◽

pp. 459-467 ◽

Cited By ~ 1

Author(s):

Mayada Tahir

Keyword(s):

Laser Irradiation ◽

Co2 Laser ◽

Thermal Damage ◽

Continuous Wave ◽

Anterior Part ◽

Outer Part ◽

Human Cornea ◽

Thermal Dose ◽

Element Analysis ◽

Reflex Blink

Cornea thermal damage due to incidental continuous wave CO2 laser irradiation is studied numerically based on bio-heat equation. The interaction of laser with tissue leads to a rapid temperature increased in target and the nearby tissue. As the temperature of the eye surface reaches 44?C, a sensation of pain will cause aversion response of the reflex blink and/or shifting away from the source of pain. The aim of the work is to predict numerically the threshold limit of incidental laser power that causes damage to the anterior part of the cornea, which can be healed within 2-5 days as long as damage is not exceeding the outer part of the eye (epithelium). A finite element analysis is used to predict temperature distribution through the cornea where the necroses region can be obtained using thermal dose equation. The thermal dose that required for damaging the cornea is predicted from previously published experimental data on rhesus monkeys and used later as a limit for shrinkage to human cornea. The result of this work is compared by international standard of safety and a good nearby result is obtained which verified the result of this work.

Download Full-text

Effect of Gamma-Ray Pre-Irradiation on the Ablation of Polyethylene and Ethylene-Propylene Copolymer Under Continuous CO2 Laser Radiation

Journal of Russian Laser Research ◽

10.1007/s10946-017-9655-3 ◽

2017 ◽

Vol 38 (4) ◽

pp. 369-374 ◽

Cited By ~ 3

Author(s):

S. R. Allayarov ◽

E. M. Tolstopyatov ◽

D. A. Dixon ◽

L. A. Kalinin ◽

P. N. Grakovich ◽

...

Keyword(s):

Laser Radiation ◽

Co2 Laser ◽

Gamma Ray ◽

Ethylene Propylene ◽

Continuous Co2 Laser ◽

Co2 Laser Radiation

Download Full-text

Cracking under Transient Temperature Distributions

The Mechanics and Reliability of Films, Multilayers and Coatings ◽

10.1017/9781316443606.013 ◽

2017 ◽

pp. 174-187

Author(s):

Matthew R. Begley ◽

John W. Hutchinson

Keyword(s):

Transient Temperature ◽

Temperature Distributions

Download Full-text

The Transient Temperature Distribution in a Slab Subject to Thermal Radiation

Journal of Heat Transfer ◽

10.1115/1.3689025 ◽

1965 ◽

Vol 87 (1) ◽

pp. 117-130 ◽

Cited By ~ 14

Author(s):

R. D. Zerkle ◽

J. Edward Sunderland

Keyword(s):

Temperature Distribution ◽

Thermal Radiation ◽

Radiant Heat ◽

Analog Computer ◽

Graphical Form ◽

Transient Temperature ◽

Transient Temperature Distribution ◽

Temperature Distributions ◽

Approximate Analytical Solutions ◽

Wide Range

The transient, one-dimensional temperature distribution is determined for a slab, insulated on one face, and subjected to thermal radiation at the other face. The slab is initially at a uniform temperature and is assumed to be homogeneous, isotropic, and opaque; the physical properties are assumed to be independent of temperature. Transient temperature distributions for both heating and cooling situations are obtained by means of a thermal-electrical analog computer. A diode limiter circuit is used to simulate the nonlinear radiant heat flux. The transient temperature distributions are presented in a dimensionless, graphical form for a wide range of variables. Approximate analytical solutions are also given which complement and extend the solution charts over ranges of parameters not covered in the charts.

Download Full-text

Thermal Analysis of Cornea Heated with Terahertz Radiation

Applied Sciences ◽

10.3390/app9050917 ◽

2019 ◽

Vol 9 (5) ◽

pp. 917

Author(s):

Wenquan Liu ◽

Yuanfu Lu ◽

Rongbin She ◽

Guanglu Wei ◽

Guohua Jiao ◽

...

Keyword(s):

Heat Transfer ◽

Thermal Analysis ◽

Terahertz Radiation ◽

Thermal Effects ◽

Thermal Damage ◽

Treatment Approach ◽

Thz Radiation ◽

Beam Radius ◽

Corneal Tissue ◽

Temperature Distributions

We numerically investigate the thermal effects in a cornea illuminated by terahertz radiation. By modifying the bioheat and Arrhenius equations, we studied the heat-transfer and temperature distributions in the corneal tissue, and evaluated the potential thermal damage. The influence of the beam radius and power density are discussed. We also estimated the effective cornea-collagen shrinkage region, and evaluated the degree of thermal damage in the cornea. We expect this work to open up a novel effective and safe thermal-treatment approach based on THz radiation for cornea reshaping in the field of ophthalmology.

Download Full-text