Thermal damage thresholds for multiple-pulse porcine skin laser exposures at 1070 nm

Abstract

As solid-state laser technology continues to mature, high-energy lasers operating in the near-infrared (NIR) band have seen increased utilization in manufacturing, medical, and military applications. Formulations of maximum permissible exposure limits establish guidelines for the safe use of these systems for a given set of laser parameters, based on past experimental and analytical studies of exposure thresholds causing injury to the skin and eyes. The purpose of our study is to characterize the skin response to multiple-pulsed laser exposures at the NIR wavelength of 1070 nm, at a constant beam diameter of 1 cm, using anesthetized Yucatan mini-pig subjects. Our study explores three constant total laser-on times of 0.01, 0.1, and 10 s as single-and multiplepulse sequences. Exposures consisting of 10, 30, and 100 pulses have identical individual pulse durations but different duty cycles in order to include variable degrees of thermal additivity. A plurality of three observers quantifies skin damage with the minimally visible lesion metric, judged at the 1-and 24-h intervals postexposure. Calculation of the median effective dose (ED 50) provides injury thresholds for all exposure conditions, based on varying laser power across subjects. The results of this study will provide a quantitative basis for the incorporation of multiple-pulsed laser exposure into standards and augment data contained in the existing ED 50 database.

Efficacy of knee osteoarthritis by use of laser acupuncture: A systematic review and meta-analysis

“…LA involves thermal energy (photothermal energy), electrical energy, and mechanical energy. [ 66 ] Under the action of an electromagnetic wave in the field, positive and negative ions in the inner and outer fluids of the cells move in opposite directions, generating action potentials and electrical signals and stimulating the receptors at the acupoints. [ 67 ]…”

“…LA involves thermal energy (photothermal energy), electrical energy, and mechanical energy. [66] Under the action of an electromagnetic wave in the field, positive and negative ions in the inner and outer fluids of the cells move in opposite directions, generating action potentials and electrical signals and stimulating the receptors at the acupoints. [67] Laser can affect the permeability of cell membranes and the activity of some enzymes and speed up the operation of nutrients by improving blood circulation, thus strengthening the body's metabolism and improving the body's functions.…”