title: Determination of the low concentration correction in the macroscopic singlet oxygen model for PDT.
abstract: The macroscopic singlet oxygen model has been used for singlet oxygen explicit dosimetry in photodynamic therapy (PDT). The photophysical parameters for commonly used sensitizers, HPPH and BPD, have been investigated in pre-clinical studies using mouse models. So far, studies have involved optimizing fitting algorithms to obtain the some of the photophysical parameters (ξ,σ,g) and the threshold singlet oxygen dose ([1O2]rx,sh), while other parameters such as the low concentration correction,δ, has been kept as a constant. In this study, using photobleaching measurements of micein vivo, the value ofδwas also optimized and fit to better describe experimental data. Furthermore, the value of the specific photobleaching ratio (σ) was also fine-tuned using the photobleaching results. Based on literature values of δ, σ for photosensitizers can be uniquely determined using the additional photobleaching measurements. This routine will further improve the macroscopic model of singlet oxygen production for use in explicit dosimetry.
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA; Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Michele M
authors.initials: MM
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Rozhin
authors.initials: R
authors.lastname: Penjweini
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Jarod C
authors.initials: JC
authors.lastname: Finlay
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Zhu
keywords: BPD; HPPH; explicit dosimetry; macroscopic model; photodynamic therapy