Singlet Oxygen Modeling for PDT Incorporating Local Vascular Oxygen Diffusion
Singlet oxygen (1O2) is the major cytotoxic agent that kills cells during photodynamic therapy (PDT). Based on a previously-developed model, the distance-dependent reacted 1O2 can be numerically calculated using finite-element method. We improved the model to include microscopic kinetic equations of oxygen diffusion from uniformly distributed blood vessels to the adjacent tissue. The blood vessel network is assumed to form a 3-D grid based on a single Krogh cylinder model with a varying vascular density. The forward calculation is performed using COMSOL Multiphysics®. Our model proves the validity of the formulation of the oxygen perfusion term used in the macroscopic singlet oxygen model.