What is PDT?

Photodynamic therapy (PDT) is used clinically to treat a wide range of medical conditions, including malignant cancers, and is recognised as a treatment strategy which is both minimally invasive and minimally toxic. While the applicability and potential of PDT has been known for over a hundred years, the development of modern PDT has been a gradual one, involving scientific progress in the fields of photobiology and cancer biology, as well as the development of modern photonic devices, such as lasers and LEDs.

Most modern PDT applications involve three key components: a photosensitizer, a light source and tissue oxygen. The wavelength of the light source needs to be appropriate for exciting the photosensitizer to produce reactive oxygen species. The combination of these three components leads to the chemical destruction of any tissues which have either selectively taken up the photosensitizer or have been locally exposed to light. In understanding the mechanism of PDT it is important to distinguish it from other light-based and laser therapies such as laser wound healing and rejuvenation which do not require a photosensitizer.


Over the last thirty years, PDT has seen considerable development in a wide range of medical applications, such as in cancer, infection control, periodontal disease, and HIV/AIDS. At the cutting edge of new PDT developments, many scientists worldwide are exploring ways of enhancing photosensitizer efficacy and targeting. The PanAmerican Photodynamic Association was established to galvanize the basic science and clinical expertise of PDT in the Americas and enable the clinical field of PDT to move forward.

To read more about PDT, please visit Wikipedia.