Open AccessDetermination of the distribution of drug concentration and tissue optical properties for ALA-mediated photodynamic therapy
Author(s) -
Yi Hong Ong,
Andrew C. Li,
Theresa M. Busch,
Timothy C. Zhu
Publication year - 2021
Publication title -
pubmed central
Language(s) - English
Resource type - Conference proceedings
SCImago Journal Rank - 0.192
H-Index - 176
pISSN - 0277-786X
DOI - 10.1117/12.2581824
Subject(s) - photosensitizer , photodynamic therapy , materials science , attenuation coefficient , fluorescence , transmittance , fluorescence spectroscopy , absorption (acoustics) , spectroscopy , optics , biological tissue , in vivo , biomedical engineering , optoelectronics , biophysics , chemistry , photochemistry , physics , medicine , organic chemistry , microbiology and biotechnology , quantum mechanics , composite material , biology
PDT efficacy depends on the availability and dynamic interactions of photosensitizer, light, and oxygen. Tissue optical properties influence the delivered light dose and impact PDT outcome. In-vivo measurements of tissue optical properties and photosensitizer concentration enable determination of explicit and implicit dose factors affecting PDT and helps to understand the underlying biophysical mechanism of PDT. In this study, we measure tissue optical properties (absorption μ a (λ) and scattering μ s ' (λ) coefficients) and PpIX concentration in tissue simulating liquid phantoms with a geometry that resembles anal canal. In-vivo light fluence rate and photosensitizer fluorescence of 405nm excitation light source were acquired using a dual-motor continuous wave transmittance spectroscopy system. We characterized the tissue optical properties correction factor of fluorescence signal using a series of tissue simulating phantoms with known PpIX concentrations and with absorption coefficient between 0.1 - 0.9 cm -1 and reduced scattering coefficient between 5 - 40 cm -1 . The results demonstrated that our spectroscopy system could determine the distribution of tissue optical properties and PPIX concentration during anal PDT.