What is PDT?
PhotoDynamic Therapy (PDT) is a type of photochemotherapy which uses the phototoxic effect of photosensitising drugs on tumour cells.
The photosensitising drug makes cells more sensitive to light and is attracted to the cancer cells. It does not become active until it is exposed to a particular type of light, usually a high-intensity laser light of a very specific wavelength. The drug is activated when this light is directed at the area of the cancer, usually by means of a flexible optical fibre or a special lamp. The energy in the light activates the drug, which destroys the cancer cells by combining with oxygen to form a short-lasting substance that is toxic to the cells. Some healthy, normal cells in the body will also be affected by PDT, but these cells will usually heal after the treatment.
The very nature of PDT means that other body tissue will remain sensitive to light for up to several weeks after treatment. Therefore it is very important for the patient to avoid direct sunlight and bright indoor light for a period afterwards; otherwise the skin gets very sensitive and may become very red and sore if it is exposed to light during this time.
PDT has been in development since the 1960s but is not particularly widely used in the UK except in dermatology. The principle reasons for this lack of acceptance are the high cost of the drugs and laser equipment.
A recent development of PDT is Intralesional PDT, or I-PDT. Please see the I-PDT page for further details.
Our PDT Services
Excel Lasers provides a range of laser products and services for PDT, including diffuser fibres, new lasers and laser systems for loan.
Excel Lasers has PDT lasers available for loan, so you do not necessarily need to make a substantial initial investment in buying your own laser. In the UK, PDT is not widely used outside of dermatology; but the situation is now improving and we are working with specialists throughout the world to develop PDT and make the procedures more generally available at affordable costs.
We can also supply brand new lasers, in a variety of wavelengths, at competitive prices.
PDT uses a long diffusing fibre tip to apply laser light evenly over a wide area. These are precision devices and Excel Lasers is a UK distributor for Medlight’s range of diffuser fibres, These are available with either plastic or high-efficiency silica delivery fibre, and diffuser lengths from 1 cm to 7 cm. These fibres are suitable for use in a number of PDT applications and with lasers of various wavelengths. Excel Lasers currently supports the most popular wavelengths of 630, 635, 652 and 670 nm, which are used with photosentitiser drugs such as Photofrin, ALA and Foscan. Applications include lung cancer, oesophageal cancer, head and neck cancers.
For further information about PDT in the UK, the best resources are the websites of the charities that are actively highlighting the benefits of PDT and raising funds to provide treatment. Here are a few of them: