Pulsed CO₂ laser tissue ablation: Effect of tissue type and pulse duration on thermal damage

TLDR

Infrared laser tissue removal causes thermal damage to surrounding tissue, which can be modulated by laser wavelength, irradiance, and exposure duration. The study examined CO₂ laser pulse widths from 2 µs to 50 ms in vivo and in vitro, correlating pulse duration and tissue thermal denaturation with the resulting damage zone. Short 2 µs CO₂ laser pulses reduced thermal damage zones from 750 µm to as little as 50 µm in guinea pig skin, with the damage width varying by tissue type and explained by a simple model linking denaturation temperature and pulse duration.

Abstract

Abstract Tissue removal by infrared lasers is accompanied by thermal damage to nonablated tissue. The extent of thermal damage can be controlled by a choice of laser wavelength, irradiance, and exposure duration. The effect of exposure duration has been studied in vivo by using CO 2 lasers with pulse widths that vary from 2 μsec to 50 msec. Pulse widths of 50 msec, typical of a shuttered, continuous‐wave CO 2 laser, produce damage regions 750 μm wide in normal guinea pig skin; the use of a 2‐μseclong pulse reduced this damage zone to as little as 50 μm. Using 2‐μseclong pulses, in vitro studies showed that the minimum zone of thermal damage varied significantly with tissue type. The thermal denaturation of these tissues has been studied and correlated with damage. The effect of denaturation temperature and pulse duration on the width of the damage zone is explained by a simple model.