Photodynamic therapy (PDT) is a treatment that uses a light-sensitive drug and a laser or light source to destroy cancer cells.
The drug is attracted to the cancer cells. But it does not become active in these cells until a light is shone on it. Using a certain light or laser will activate the drug to release a type of oxygen that kills the nearby cancer cells.
Some healthy, normal cells in the body will also be affected by PDT, but these cells usually recover after treatment.
PDT is not widely available around the UK, so you may have to travel to have it.