Calculation of isofluence contours for PDT application

Stefan B. Spaniol; Dagmar Kobe; Volkhard Abraham; Peter Nothof; Stephan Schmidt; Dieter Krebs; Wolfgang Ertmer

doi:10.1117/12.182941

17 August 1994 Calculation of isofluence contours for PDT application

Stefan B. Spaniol, Dagmar Kobe, Volkhard Abraham, Peter Nothof, Stephan Schmidt, Dieter Krebs, Wolfgang Ertmer

Proceedings Volume 2134, Laser-Tissue Interaction V; and Ultraviolet Radiation Hazards; (1994) https://doi.org/10.1117/12.182941
Event: OE/LASE '94, 1994, Los Angeles, CA, United States

Abstract

The aim of this study was to calculate the light fluence for various PDT applications with a Monte Carlo method. Different applicator geometries and the related illuminations are computed in a 3D-multilayer tissue model. The applicators we calculated include various surface geometries, intensity and angular profiles as well as tissue parameter variations, and different wavelengths. The resulting fluence contours in conjunction with a certain dye concentration allow a prediction of the expected damage zone after PDT in the tumor tissue. To measure tissue parameters ex vivo we built up a spectrometer consisting of two integrating spheres. The light source we use is a cw Ti:sapphire laser tunable from about 670 nm to 760 nm without change of optics. We use a combination of direct and indirect measurements. By estimating the specular reflection and direct transmission from a tissue sample (approximately 490 micrometers ) we get the refractive index n and the extinction coefficient (mu) _(tau ). We also measure the diffuse reflection as well as the diffuse transmission with the integrating spheres. To calculate the missing parameters (mu) _a and g we use an inverse Monte Carlo simulation (MCS) with the Henyey-Greenstein phase function. Simulation of the tissue sample including the boundary and geometry effects leads to absorption coefficients that are up to a factor of 3 lower in comparison to good analytical models. The loss of diffuse light can be taken into consideration.

Citation Download Citation

Stefan B. Spaniol, Dagmar Kobe, Volkhard Abraham, Peter Nothof, Stephan Schmidt, Dieter Krebs, and Wolfgang Ertmer "Calculation of isofluence contours for PDT application", Proc. SPIE 2134, Laser-Tissue Interaction V; and Ultraviolet Radiation Hazards, (17 August 1994); https://doi.org/10.1117/12.182941

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
7 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Photodynamic therapy

Tissues

Monte Carlo methods

Integrating spheres

Refractive index

Statistical analysis

Tissue optics

Show All Keywords

Keywords/Phrases

Search In:

Publication Years