Significance of Blood Flow in Calculations of Temperature in Laser Irradiated Tissue

Welch, Ashley J.; Wissler, Eugene H.; Priebe, Leslie A.

doi:10.1109/tbme.1980.326619

Cited by 93 publications

(37 citation statements)

References 4 publications

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“…13 In addition, as no in vivo study on chronological changes of coagulation depth after APC irradiation was carried out, it is difficult to assume that deeper damage would not become apparent within a few days after treatment.…”

Section: Discussionmentioning

confidence: 99%

Argon plasma coagulation for successful treatment of early gastric cancer with intramucosal invasion

Sagawa

Takayama²,

Oku³

et al. 2003

Gut

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Section: Discussionmentioning

confidence: 99%

Argon plasma coagulation for successful treatment of early gastric cancer with intramucosal invasion

Sagawa

Takayama²,

Oku³

et al. 2003

Gut

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“…37 Adiabatic boundary conditions were applied at z ϭ ϱ and x ϭ Ϯϱ. A constant initial temperature of 33°C was used for the entire tissue volume.…”

Section: B Heat-transfer Modelmentioning

confidence: 99%

Optimum pulse duration and radiant exposure for vascular laser therapy of dark port-wine skin: a theoretical study

Tunnell¹,

Wang²,

Anvari³

2003

Appl. Opt.

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Laser therapy for cutaneous hypervascular malformations such as port-wine stain birthmarks is currently not feasible for dark-skinned individuals. We study the effects of pulse duration, radiant exposure, and cryogen spray cooling ͑CSC͒ on the thermal response of skin, using a Monte Carlo based optical-thermal model. Thermal injury to the epidermis decreases with increasing pulse duration during irradiation at a constant radiant exposure; however, maintaining vascular injury requires that the radiant exposure also increase. At short pulse durations, only a minimal increase in radiant exposure is necessary for a therapeutic effect to be achieved because thermal diffusion from the vessels is minimal. However, at longer pulse durations the radiant exposure must be greatly increased. There exists an optimum pulse duration at which minimal damage to the epidermis and significant injury within the targeted vasculature occur. For example, the model predicts optimum pulse durations of approximately 1.5, 6, and 20 ms for vessel diameters of 40, 80, and 120 m, respectively. Optimization of laser pulse duration and radiant exposure in combination with CSC may offer a means to treat cutaneous lesions in dark-skinned individuals.

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“…Subscripts e and bd stand for epidermal layer and bloody dermal layer, respectively. Due to a short time period involved in CSC and pulsed laser irradiation, the blood perfusion effect is safely neglected [29,30]. On the skin surface the standard convection condition is used to describe the cooling effect of CSC: …”

Section: Light Distribution and Heat Transfer In Epidermis And Bloodymentioning

confidence: 99%

A new model of selective photothermolysis to aid laser treatment of port wine stains

Liu

Wang

et al. 2013

Chin. Sci. Bull.

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Pulsed dye lasers equipped with cryogen spray cooling (CSC) are now widely used to treat vascular malformation such as port wine stains (PWSs). This paper presents a new integrated model that can quantitatively simulate the cooling of the skin and the heating of the targeted blood vessels in PWSs during laser treatment. The new model is based on the classical homogeneous multi-layer skin model that treats PWS-containing dermis as a mixture of dermal tissue and homogeneously distributed blood. Light propagation in skin and PWSs is simulated by a Monte-Carlo method, which provides accurate description of the light scattering and absorption in the skin. Thermal response of a targeted vessel in the new model is then obtained from the thermal analysis of a Krogh-unit that consists of the vessel and the surrounding dermal tissues and is buried in PWSs. The results from the multi-layer skin model provide appropriate laser influence input as well as the initial thermal condition for the micro-model of the Krogh-unit. A general dynamic relation is also introduced on the surface of skin to quantify the convective cooling of CSC. The model is then applied to dye-laser treatment (wavelength of 585 nm) of PWSs with CSC. Numerical results demonstrate that the present model is able to quantify thermal response of a deeply buried blood vessel in PWSs as a discrete blood vessel does, with a more realistically estimate of the sheltering effect of the dermal tissue (scattering) and blood vessels (absorption) in front of the targeted vessel. To understand the poor response of PWSs in clinic, the thermal characteristics of a targeted vessel was simulated under various conditions. The effects of two morphological parameters, the vessel diameter and the burying depth of the vessel, are then systematically investigated under various pulse durations and fluences of laser. A threshold fluence for given vessel diameter and depth is then estimated quantitatively under the condition of the optimal laser pulse duration. The results indicate that significant high threshold fluence is needed for large vessels buried deeply in the dermis, explaining the physics of the difficulty in clinic of complete clearance of PWSs. The results provide guidance to the clinic selection of the laser pulse duration and laser energy fluence for given PWSs.

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Significance of Blood Flow in Calculations of Temperature in Laser Irradiated Tissue

Cited by 93 publications

References 4 publications

Argon plasma coagulation for successful treatment of early gastric cancer with intramucosal invasion

Argon plasma coagulation for successful treatment of early gastric cancer with intramucosal invasion

Optimum pulse duration and radiant exposure for vascular laser therapy of dark port-wine skin: a theoretical study

A new model of selective photothermolysis to aid laser treatment of port wine stains

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