Photodynamic therapy (PDT) is a potential treatment regime for a number of conditions. It involves introducing particular light-sensitive chemical species into biological systems, inducing them to localize at the point of interest, and then irradiating them with a light source.

It holds particular promise as a treatment to combat certain cancers, and the latest results from trials using a system developed by Ontario-based Theralase have shown that PDT was able to completely destroy subcutaneous colon cancer tumors in a mouse model. Four weeks after treatment, the mice remained free of cancer.