Numerical evaluation of heat-triggered drug release via thermo-sensitive liposomes: A comparison between image-based vascularized tumor and volume-averaged porous media models

In this study, two numerical models for controlled drug delivery through thermo-sensitive liposomes under mild microwave hyperthermia are compared. The first model simulates blood flow directly in a realistic tumor vascular network. The second one, at the volume-averaged macro scale, employs the porous media model. Using the vascular-scale approach is helpful for these kind of applications since the porous media assumption does not allow to account for local vascular blood flow, which is a crucial variable to quantify outputs like local drug accumulations. In the present study, the vascularized tumor model is obtained from a photo-acoustic scan and used as computational domain. The vascular-scale model considers heat and drug transfer in vascular and intracellular spaces, employing energy equations for heat transfer and a three-compartment convection-diffusion model for drug diffusion. Blood flow is simulated using the momentum equation for non-Newtonian fluids. The volume-averaged model shows good agreement with the vascular-scale model even if provides less precise information about temperature field distribution and drug localization within the tumor tissue. Also, the volume-averaged model underestimates Fraction of Killed Cells by 3 % post-treatment, presenting a more uniform temperature field and drug distribution compared to the vascular-scale one. Despite these small limitations, the porous media model is reliable for obtaining average results, while the vascular-scale model is suitable when more accurate results are needed. This study's findings aid those who aim to predict hyperthermia-driven drug delivery, suggesting the vascular-scale approach for precision and accuracy and the volume-averaged approach for average