Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Home > Photodynamic therapy
Photodynamic therapy (PDT) is a ternary treatment involving the use of a photosensitizer , administered light and tissue oxygen. A sensitizer or metabolic precursor of a sensitizer is administered. After certain time photosensitizer molecules have accumulated in diseased cells. Then light of specific wavelength is administered to the treatment site. A molecule of the sensitizer absorbs a photon of light and is excited to the first excited singlet state. If this singlet state is long lived energy can be transferred from the singlet state to the triplet excited state through interstitial crossing. This triplet state is able to transfer energy to another triplet. One of the very few molecules with a triplet ground state is dioxygen, which is found in most cells. Energy transfer therefore takes place to afford singlet oxygen from ground state oxygen, provided the energy of the excited triplet state sensitizer molecule is higher than that of the singlet oxygen product. Singlet oxygen is highly toxic damaging tissue and triggering apoptosis.
Photodynamic therapy is a tissue saving treatment in certain cancer indications. Non-cancer indications can be e.g. psoriasis, Age Related Macular Degeneracy , acne, etc.
External links
Read more »