PDT Involves two steps.
First, a light-sensitive drug is given. For skin cancers, it may be a cream. For internal cancers, it may be an injection into a vein, or rarely a drink. You then wait a few hours to a few days before the next step. This allows time for the drug to concentrate in the cancer cells.
Next, a special light (usually a laser) is shone onto the cancer. The light activates the drug to treat the tumour. If the cancer is internal, an ultrasound or scan may be used to guide the light source to the tumour.
The side effects can vary depending on where treatment is given, what drugs are used, and how you react. You may become sensitive to light for a time, and will need to take care in the sun, or other bright lights.
How PDT works
Photodynamic therapy (PDT) is a treatment that uses a light-sensitive drug and a laser or light source to destroy cancer cells.
The light-sensitive drug is sometimes called the photosensitising agent. It is a drug that makes cells more sensitive to light. This is called photosensitivity.
The drug is attracted to the cancer cells. It does not become active until it is exposed to a particular type of light. When the light is directed at the area of the cancer, the drug is activated and the cancer cells are destroyed. Some healthy, normal cells in the body will also be affected by PDT, but these cells will usually heal after the treatment.