Photodynamic therapy

What is Photodynamic therapy?

Photodynamic therapy (PDT), sometimes called photochemotherapy, is a form of phototherapy using nontoxic light-sensitive compounds that are exposed selectively to light, whereupon they become toxic to targeted malignant and other diseased cells (phototoxicity). PDT has proven ability to kill microbial cells, including bacteria, fungi and viruses. PDT is popularly used in treating acne. It is used clinically to treat a wide range of medical conditions, including wet age-related macular degeneration and malignant cancers, and is recognised as a treatment strategy which is both minimally invasive and minimally toxic.

Most modern PDT applications involve three key components: a photosensitizer, a light source and tissue oxygen. The combination of these three components leads to the chemical destruction of any tissues which have both selectively taken up the photosensitizer and have been locally exposed to light. The wavelength of the light source needs to be appropriate for exciting the photosensitizer to produce reactive oxygen species. These reactive oxygen species generated through PDT are free radicals (Type I PDT) generated through electron abstraction or transfer from a substrate molecule and highly reactive state of oxygen known as singlet oxygen (Type II PDT). In understanding the mechanism of PDT it is important to distinguish it from other light-based and laser therapies such as laser wound healing and rejuvenation, or intense pulsed light hair removal, which do not require a photosensitizer.

Questions and answers on "Photodynamic therapy"

sir, i have got csr problem on both left and right eye, and first time i got csr problem on 1996 and at that time i almost lost my right eye vision...

doctor1 MD

Dear Priya,Hi,CSR as you know is called central serous retinopathy or in simple terms accumulation of fluid in the central part of the retina due...

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I am currently having PDT by my dermatologist and have had two treatments with the Levulan and Gentle Waves but have seen no changes at all. I...

doctor1 MD

Hello and welcome to HCM,
You have nodulocystic acne and photodynamic therapy works well for it. But every individual has different things working...

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I´m diagnosticated with Hailey-Hailey 5 years ago. Now I suffers with constant breakouts ranging from the rash , the open sores that ooze fluid ,...

doctor1 MD

Hello bab,
here on hcm.
Unfortunately there is no cure for Hailey-Hailey disease. Treatment is aimed at reducing symptoms and preventing...

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