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Proceedings Paper

In vivo wide-field multispectral dosimeter for use in ALA-PpIX based photodynamic therapy of skin
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Paper Abstract

Photodynamic therapy (PDT) for Actinic Kertoses (AK) using aminoluvelinic acid (ALA) is an FDA-approved treatment, which is generally effective, yet response rates vary. The origin of the variability is not well characterized, but may be related to inter-patient variability in the production of protoporphyrin IX (PpIX). While fiber-based point probe systems provide a method for measuring PpIX production, these measurements have demonstrated large spatial and inter-operator variability. Thus, in an effort to improve patient-specific dosimetry and treatment it is important to develop a robust system that accounts for spatial variability and reduces the chance of operator errors. To address this need, a wide-field multispectral imaging system was developed that is capable of quantifying maps of PpIX in both liquid phantoms and in vivo experiments, focusing on high sensitivity light signals. The system uses both red and blue excitation to elicit a fluorescent response at varying skin depths. A ten-position filter wheel with bandpass filters ranging from 635nm to 710nm are used to capture images along the emission band. A linear least-square spectral fitting algorithm provides the ability to decouple background autofluorescence from PpIX fluorescence, which has improved the system sensitivity by an order of magnitude, detecting nanomolar PpIX concentrations in liquid phantoms in the presence of 2% whole blood and 2% intralipid.

Paper Details

Date Published: 8 February 2017
PDF: 8 pages
Proc. SPIE 10047, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XXVI, 1004707 (8 February 2017); doi: 10.1117/12.2252402
Show Author Affiliations
Ethan P. M. LaRochelle, Thayer School of Engineering at Dartmouth (United States)
Scott C. Davis, Thayer School of Engineering at Dartmouth (United States)
Ana Luiza Ribeiro de Souza, Thayer School of Engineering at Dartmouth (United States)
CAPES Foundation (Brazil)
Brian W. Pogue, Thayer School of Engineering at Dartmouth (United States)


Published in SPIE Proceedings Vol. 10047:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XXVI
David H. Kessel; Tayyaba Hasan, Editor(s)

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