Photodynamic therapy (PDT) has been theoretically investigated using a Monte Carlo radiation transfer (MCRT)
model. By including complex three dimensional (3D) tumour models a more appropriate representation of the
treatment was achieved. The 3D clustered tumour model was compared to a smooth model, resulting in a
significantly deeper penetration associated with the clustered model. The results from the work presented here
indicates that light might penetrate deeper than suggested by 2D or simple layered models.
The effects of ageing and skin type on Photodynamic Therapy (PDT) for different treatment methods have been theoretically investigated. A multilayered Monte Carlo Radiation Transfer model is presented where both daylight activated PDT and conventional PDT are compared. It was found that light penetrates deeper through older skin with a lighter complexion, which translates into a deeper effective treatment depth. The effect of ageing was found to be larger for darker skin types. The investigation further strengthens the usage of daylight as a potential light source for PDT where effective treatment depths of about 2 mm can be achieved.