Photodynamic Therapy
(PDT or Blue Light Therapy)
Gary W. Cole, MD, FAAD
Dr. Cole is board certified in dermatology. He obtained his BA degree in bacteriology, his MA degree in microbiology, and his MD at the University of California, Los Angeles. He trained in dermatology at the University of Oregon, where he completed his residency.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
- What is photodynamic therapy (PDT)?
- What photosensitizer drugs are available?
- What light sources are available, and how are they applied?
- How does photodynamic therapy work?
- Does PDT make me permanently more sensitive to light?
- How is PDT used to treat the skin?
- What is a typical skin PDT session like?
- How much improvement can I expect with photodynamic therapy?
- Where can I have photodynamic therapy, and who performs the procedure?
- What are the advantages with photodynamic therapy for treating actinic keratosis?
- Am I a good candidate for photodynamic therapy?
- What growths is PDT not good for?
- What are possible complications of photodynamic therapy?
- Is there scarring from photodynamic therapy?
- What are alternatives for photodynamic therapy?
- What about insurance coverage and costs of photodynamic therapy?
- How do I prepare for my procedure?
- How is recovery after PDT?
- Is there pain after PDT?
- How do I take care of my treatment area after photodynamic therapy?
- What is the chance that my actinic keratoses will recur?
- Patient Comments: Photodynamic Therapy - Skin
- Patient Comments: Photodynamic Therapy - Experience
- Find a local Dermatologist in your town
What is photodynamic therapy (PDT)?
Photodynamic therapy (PDT) is a medical treatment that uses a photosensitizing drug (a drug that becomes activated by light exposure) and a light source to activate the applied drug. The result is an activated oxygen molecule that can destroy nearby cells. Very thin superficial skin cancers called actinic keratoses and certain other types of cancer cells can be eliminated this way. The procedure is easily performed in a physician's office or outpatient setting.
PDT essentially has three steps. First, a light-sensitizing liquid, cream, or intravenous drug (photosensitizer) is applied or administered. Second, there is an incubation period of minutes to days. Finally, the target tissue is then exposed to a specific wavelength of light that then activates the photosensitizing medication.
Steps:
- application of photosensitizer drug
- incubation period
- light activation
Although first used in the early 1900s, PDT in the modern sense is a fairly new, evolving science. Current PDT involves a variety of incubation times for the light-sensitizing drug and a variety of light sources depending on the target tissue. The basic premise of PDT is selective tissue destruction. Although the photosensitizer may be absorbed all over by many cells, atypical or cancerous cells take up more of the drug and retain the drug for a longer duration than normal tissues. Then light energy is applied selectively to the appropriate tissue.
At present, the primary limitation of available PDT techniques is the depth of penetration of the light and ability to target cells within at most 1/3 of an inch (approximately 1 cm) of the light source. Therefore, tumors or atypical growths must be close to the surface of the skin or treatment surface for PDT to work.
PDT is currently used in a number of medical fields, including oncology (cancer), dermatology (skin), and cosmetic surgery.
In oncology, it is FDA approved for non-small cell lung cancer, esophageal cancer, and precancerous changes of Barrett's esophagus. Its use is also being further investigated through clinical trials in general oncology for conditions including cancers of the cervix (mouth of uterus), prostate gland, brain, and peritoneal cavity (the abdominal space that contains the stomach, liver, and internal organs).
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| Levulan stick (photosensitizer medication) |
In dermatology, PDT with the photosensitizer Levulan Kerastick® (20% delta-aminolevulinic acid HCl) is used for the treatment of very early, thin skin cancers called actinic keratoses (AK). The initial approval was specifically for the treatment of actinic keratosis of the face and scalp with a combination of an application of the photosensitizer followed by a timed exposure to a special blue light source. PDT is also used for acne, rosacea, skin cancer, sun damage, cosmetic skin improvement, oily skin, enlarged sebaceous glands, wrinkles, rejuvenation (anti-aging), warts, hidradenitis suppurativa, psoriasis, and many other skin conditions. It is not used to remove moles or birthmarks.
Learn more about: Levulan Kerastick
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| Application of Levulan to the face |
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