Photodynamic therapy (PDT) is a non-thermal technique for local treatment of tumours. This treatment modality is well accepted for several clinical indications, both cancer and benign diseases. A substance called a photosensitising agent (photosensitiser) is pre-administered to the body and the tumour is then illuminated with light of a specific wavelength, often in the red wavelength region. A photochemical reaction is induced as the photosensitiser absorbs the light, causing an excitation of ground state oxygen in the tissue to singlet oxygen. Singlet oxygen reacts with cellular targets such as plasma membranes, mitochondria and lysosomes, leading to damage of the biological tissue. The tumour damage, caused by the photodynamic therapy is caused by a combination of vascular destruction, which starves the tumour cells as no oxygen or nutrients are delivered to the tumour mass, and apoptosis and necrosis.

The research concerning Photodynamic therapy, within the group, is mainly devoted to the development of dosimetry algorithms for improved therapeutic outcome of interstitial photodynamic therapy of prostate cancer. This work is conducted in close connection to SpectraCure AB.