5ALAinduced

5-ALA induced refers to the biological and diagnostic effects that follow administration of 5-aminolevulinic acid (5-ALA). 5-ALA is a natural precursor in heme synthesis. When given exogenously, cells convert it into protoporphyrin IX (PpIX), a fluorescent compound. Tumor and precancerous tissues often accumulate higher levels of PpIX than normal tissues, producing a distinct visual signal when excited by specific wavelengths of light. This phenomenon is commonly described as 5-ALA–induced fluorescence or 5-ALA–induced PpIX fluorescence.

Clinical use of 5-ALA–induced fluorescence is most prominent in fluorescence-guided procedures. In neurosurgery, oral 5-ALA is used to help delineate tumor margins in gliomas and other brain tumors, allowing surgeons to distinguish malignant tissue from normal brain during resection under blue light that excites PpIX. In dermatology, 5-ALA is used in photodynamic therapy and diagnostic procedures for actinic keratoses, basal cell carcinomas, and other superficial lesions, with PpIX acting as the photoactive agent activated by light to destroy abnormal cells.

Administration and pharmacology vary by indication. Oral 5-ALA dosing is typically given several hours before visualization or treatment, with peak PpIX formation occurring within a few hours and lasting into the following day. Topical or formulated derivatives may be used for skin conditions. A common clinical consideration is temporary photosensitivity; light avoidance for about 24 hours (and, in some cases, longer) is advised after 5-ALA administration.

Safety concerns include nausea, vomiting, headache, and skin sensitivity. Porphyria and certain hepatic or renal conditions may affect use. While highly useful, 5-ALA–induced fluorescence has limitations, including false negatives in some tumors and variable PpIX accumulation between lesions.