Photodynamic therapy (PDT) is a selective therapeutic approach involving uptake of a sensitizer by the target cells followed by their destruction on lightinduced activation of the chemical. Although the technique was discovered at the turn of the 20th century, its widespread use has awaited the development of suitable drugs and light sources (Brown, 1999). It is now being applied to a range of malignant and non-malignant disorders, with a continual expansion in its licensed indications.