What is photodynamic therapy (PDT)?

Photodynamic therapy (PDT) destroys harmful cells, including cancer cells, using specialized drugs called photosensitizers or photosensitizing agents. Light activates these drugs and creates a chemical reaction that destroys the harmful cells.

Doctors use PDT to treat a variety of medical conditions, including:

During treatment, providers apply photosensitizer medication directly to your skin or inject them into your bloodstream. The photosensitizing drugs concentrate in cancer cells and other unhealthy cells to make those cells more sensitive to light.

After applying the photosensitizer, your doctor shines a special light on the area undergoing treatment. Depending on the type of photosensitizer used, your doctor may use low-power red laser light, blue light or natural sunlight. Under the light, the photosensitizing agent reacts with oxygen, causing a chemical reaction that destroys unhealthy cells.

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