ELI5: Explain Like I'm 5

Photodynamic therapy

Photodynamic therapy is a type of treatment that uses light and specific drugs called photosensitizers to kill cancer cells. First, the doctor gives you a drug that goes through your body and collects in cancer cells. Then, the doctor shines a special type of light on the cancer cells. The light makes the photosensitizer give off energy that destroys the cancer cells, but it doesn't affect healthy cells around them.