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A Monte Carlo model of steady-state light transport in multi-layered tissues (MCML) has been coded in ANSI Standard C; therefore, the program can be used on various computers. Dynamic data allocation is used for MCML, hence the number of tissue layers and grid elements of the grid system can be varied by users at run time. The coordinates of the simulated(More)
A review of reported tissue optical properties summarizes the wavelength-dependent behavior of scattering and absorption. Formulae are presented for generating the optical properties of a generic tissue with variable amounts of absorbing chromophores (blood, water, melanin, fat, yellow pigments) and a variable balance between small-scale scatterers and(More)
Intralipid is an intravenous nutrient consisting of an emulsion of phospholipid micelles and water. Because Intralipid is turbid and has no strong absorption bands in the visible region of the electromagnetic spectrum, and is readily available and relatively inexpensive, it is often used as a tissue simulating phantom medium in light dosimetry experiments.(More)
The relationship of charge density per phase, or QD/ph (expressed in units of microcoulombs per cm2 per phase of the charge-balanced wave form), and total charge (QDt) to neural damage has been investigated by light and electron microscopy after surface stimulation of the parietal cortex in normal cats. QD/ph values ranging from 40 to 400 were achieved by(More)
BACKGROUND AND DESIGN The clinical objective in the treatment of a patient with port-wine stain (PWS) undergoing laser therapy is to maximize thermal damage to the PWS, while at the same time minimizing nonspecific injury to the normal overlying epidermis. With dynamic cooling, the epidermis can be cooled selectively. When a cryogen spurt is applied to the(More)
We report the development of a heterogeneous resin-tube model to study the influence of blood vessels on the apparent absorption of the system, mu a(sys), using a time-resolved technique. The experimental results show that mu a(sys) depends on the absorption inside the tubes, mu a(tube), tube diameters, and tube-to-sample volume ratios. A mathematical(More)
The Theoretical study of thermal damage processes in laser irradiated tissue provides further insight into the design of optimal coagulation procedures. Controlled laser coagulation of tissue was studied theoretically using a finite element method with a modulating laser heat source to simulate feedback controlled laser delivery with a constant surface(More)
Linearly polarized light that illuminates skin is backscattered by superficial layers and rapidly depolarized by birefringent collagen fibers. It is possible to distinguish such superficially backscattered light from the total diffusely reflected light that is dominated by light penetrating deeply into the dermis. The method involves acquisition of two(More)
Finite-width light distributions in arterial tissue during Argon laser irradiation (476 nm) are simulated using the Monte Carlo method. Edge effects caused by radial diffusion of the light extend +/- 1.5 mm inward from the perimeter of a uniform incident beam. For beam diameters exceeding 3 mm the light distribution along the central axis can be described(More)
An overview of laser-tissue interactions is presented in terms of the physical mechanisms of interaction, the time course of tissue response, and the level of biologic structure affected. The factors that affect dosimetry of photodynamic therapy are presented. Laser dosimetry for photothermal and photomechanical interactions is outlined.