Modeling the oxygen microheterogeneity of tumors for photodynamic therapy dosimetry

Brian W. Pogue; Keith D. Paulsen; Julia A. O'Hara; P. Jack Hoopes D.V.M.; Harold Swartz

doi:10.1117/12.379892

29 March 2000 Modeling the oxygen microheterogeneity of tumors for photodynamic therapy dosimetry

Brian W. Pogue, Keith D. Paulsen, Julia A. O'Hara, P. Jack Hoopes D.V.M., Harold Swartz

Proceedings Volume 3909, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy IX; (2000) https://doi.org/10.1117/12.379892
Event: BiOS 2000 The International Symposium on Biomedical Optics, 2000, San Jose, CA, United States

Abstract

Photodynamic theory of tumors uses optical excitation of a sensitizing drug within tissue to produce large deposits of singlet oxygen, which are thought to ultimately cause the tumor destruction. Predicting dose deposition of singlet oxygen in vivo is challenging because measurement of this species in vivo is not easily achieved. But it is possible to follow the concentration of oxygen in vivo, and so measuring the oxygen concentration transients during PDT may provide a viable method of estimating the delivered dose of singlet oxygen. However modeling the microscopic heterogeneity of the oxygen distribution within a tumor is non-trivial, and predicting the microscopic dose deposition requires further study, but this study present the framework and initial calibration needed or modeling oxygen transport in complex geometries. Computational modeling with finite elements provides a versatile structure within which oxygen diffusion and consumption can be modeled within realistic tissue geometries. This study develops the basic tools required to simulate a tumor region, and examines the role of (i) oxygen supply and consumption rates, (ii) inter- capillary spacing, (iii) photosensitizer distribution, and (iv) differences between simulated tumors and those derived directly from histology. The result of these calculations indicate that realistic tumor tissue capillary networks can be simulated using the finite element method, without excessive computational burden for 2D regions near 1 mm², and 3D regions near 0.1mm³. These simulations can provide fundamental information about tissue and ways to implement appropriate oxygen measurements. These calculations suggest that photodynamic therapy produces the majority of singlet oxygen in and near the blood vessels, because these are the sites of highest oxygen tension. These calculations support the concept that tumor vascular regions are the major targets for PDT dose deposition.

Citation Download Citation

Brian W. Pogue, Keith D. Paulsen, Julia A. O'Hara, P. Jack Hoopes D.V.M., and Harold Swartz "Modeling the oxygen microheterogeneity of tumors for photodynamic therapy dosimetry", Proc. SPIE 3909, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy IX, (29 March 2000); https://doi.org/10.1117/12.379892

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