Correction of fluorescence for depth-specific optical and vascular properties using reflectance and differential path-length spectroscopy during PDT

F. van Zaane; T. A. Middelburg; H. S. de Bruijn; A. van der Ploeg-van den Heuvel; E. R. M. de Haas; H. J. C. M. Sterenborg; H. A. M. Neumann; D. J. Robinson

doi:10.1117/12.822946

13 July 2009 Correction of fluorescence for depth-specific optical and vascular properties using reflectance and differential path-length spectroscopy during PDT

F. van Zaane, T. A. Middelburg, H. S. de Bruijn, A. van der Ploeg-van den Heuvel, E. R. M. de Haas, H. J. C. M. Sterenborg, H. A. M. Neumann, D. J. Robinson

Author Affiliations +

Proceedings Volume 7380, Photodynamic Therapy: Back to the Future; 73803Q (2009) https://doi.org/10.1117/12.822946
Event: 12th World Congress of the International Photodynamic Association, 2009, Seattle, Washington, United States

Abstract

Introduction: The rate of PpIX fluorescence photobleaching is routinely used as a dose metric for ALA-PDT. Diffuse reflection spectroscopy is often used to account for variations in tissue optical properties at the photosensitizer excitation and emission bands. It can be used to quantify changes in vascular parameters, such as blood volume fraction and saturation, and can aid understanding of tissue response to PDT. The volume and(/or) depth over which these signals are acquired are critical. The aim of this study is to use quantitative reflectance spectroscopy (DPS) to correct fluorescence for changes in tissue optical properties and monitor PDT. Materials & Methods: ALA was topically applied to hairless mice skin and the incubated spot was treated with PDT according to fractionated illumination schemes. DPS measurements of vascular parameters and optical properties were performed directly before and after illumination. Both the differential signal, delivery-and-collection-fiber signal and the collection fiber signal, which all probe different measurement volumes, are analyzed. Results & Conclusions: Analysis of DPS measurements shows that at the depth where most fluorescence originates, there is almost no blood present. During PDT vascular parameters at this depth stay constant. In more oxygenated layers of the tissue, the optical properties do change during PDT, suggesting that only a small part of PpIX fluorescence originates from the interesting depths where vascular response occurs. Correcting fluorescence emission spectra for optical changes at specific depths and not for the total of changes in a larger volume, as is usually done now, can improve PpIX photobleaching based treatment monitoring.

Citation Download Citation

F. van Zaane, T. A. Middelburg, H. S. de Bruijn, A. van der Ploeg-van den Heuvel, E. R. M. de Haas, H. J. C. M. Sterenborg, H. A. M. Neumann, and D. J. Robinson "Correction of fluorescence for depth-specific optical and vascular properties using reflectance and differential path-length spectroscopy during PDT", Proc. SPIE 7380, Photodynamic Therapy: Back to the Future, 73803Q (13 July 2009); https://doi.org/10.1117/12.822946

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
9 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Photodynamic therapy

Tissue optics

Luminescence

Blood

Optical properties

Skin

Tissues

Show All Keywords

Keywords/Phrases

Search In:

Publication Years