Photodynamic Therapy (PDT) is a treatment that uses special drugs called photosensitizing agents, along with light, to kill cancer cells and treat certain skin condition. These photosensitizing agents only work after they have been activated or “turned on” by specific wavelengths of light.
Depending on which part of the body is being treated, the photosensitizing agent is either injected into the bloodstream or applied directly onto the skin. Over a certain amount of time the drug is absorbed by the cancer cells. Light is then applied to the treatment area using an optical fiber.
The light triggers a photochemical reaction but does not cause any heat damage. Instead, it causes the drug to react with oxygen, which forms a chemical that kills the targeted cells. PDT also helps by destroying blood vessels that feed cancer cells and by alerting the immune system to attack the cancer.
Laserglow offers a wide range of fiber coupled laser light sources that are ideally suited for PDT.
The most common wavelengths used in PDT are between 633nm-760nm (depending on the photosensitizing agent used) with typical fiber coupled output powers between 500mW and 2W.
Studies have shown that PDT can work as well as surgery or radiation therapy in treating certain kinds of cancers and pre-cancers. It has several advantages over traditional treatments:
No long-term side effects when used properly.
Less invasive than surgery.
Short procedure, most often done outpatient.
Can be targeted very precisely.
Unlike radiation, PDT can be repeated many times on the same site if needed.
Little to no scarring after the site heals.
Costs less than traditional cancer treatments.
But PDT has limits too:
PDT can only treat areas where light can reach. This means it’s mainly used to treat problems on or just under the skin, or in the lining of organs that can be reached with a light source. Because light can’t travel very far through body tissues, PDT can’t be used to treat large cancers or cancers that have grown deeply into the skin or other organs.
PDT can’t be used to treat cancers that have spread to multiple places in the body.
The drugs used for PDT leave people very sensitive to light for some time, so special precautions must be taken after the drugs are applied to the body.
PDT can’t be used on people who have certain blood diseases, such as any of the porphyrias (a rare group of diseases that affect the skin or nervous system) or people who are allergic to porphyrins. This allergy is rare, but it may happen in those who have gotten porphyrins in the past.