The aim of this study is to determine if contrast-enhanced micro-computed tomography can be used to non-invasively image the response of vasculature in tumours that have been treated with photodynamic theraphy (PDT). The subjects used were C3H mice with RIF-1 tumour implanted subcutaneously and allowed to grow for 3 weeks prior to treatment. The subjects in this study were divided into PDT treated groups (150 J/cm², 50 J/cm²) and control groups (150 J/cm² light-only, untreated). The contast-enhanced micro-computed tomography imaging procedure consisted of eight-second scans taking place before treatment and up to 24 hours after treatment. The treatment response was evaluated through the ration of blood-to-tumour volume. Significant changes were detected at 8 and 24 hours in the 150 J/cm² PDT group (p< 0.01). Immunohistochemical staining confirmed the effects of each treatment in comparison to the control groups.