Grant: Collaborative Health Research Projects (NSERC partnered)

In Radiotherapy, dosimetry and treatment planning are highly advanced for ionizing radiation. Radiation dose is accurately defined and the relationship between it and clinical response is well understood. For photodynamic therapy (PDT), the definition of PDT dose is unclear and how it correlates with clinical response has yet to be precisely defined. Present-day clinical protocols for PDT of non-melenoma skin cancer (NMSC) are relatively straight-forward: a photosensitizer is administered, a period of time elapses before shining light and then light with a specific fluence rate illuminates the patient. The same protocol is applied to an entire patient population and as a result, PDT of NMSC is conducted without detailed customized planning that takes into account patient to patient variability as practiced in radiotherapy. Our research goal is to work on in vivo measurement of optical properties and functional parameters such as oxygen levels together with measuring the temporal and spatial photosensitizer concentration uptake. With these quantitative metrics, the hope is that we will be able to model and predict the response of individual patients to PDT.. Better dosimetry will advance the development and utilization of PDT similar to radiation therapy where the field is very quantitative and evidence-based. Ultimately patient-specific planning of PDT treatment will increase NMSC clinical outcomes.