NCIt definition : The hydrochloride salt form of hexaminolevulinate, a hexyl ester of the heme precursor
5-aminolevulinic acid (ALA) with potential photosensitizing activity. Hexaminolevulinate
serves as a precursor of photoactive porphyrins (PAPs), particularly protoporphyrin
IX (PpIX), which selectively accumulate in rapidly proliferating cells, such as those
seen in tumor tissue. When exposed to blue light, PAPs are activated and emit red
light thereby allowing tumor imaging.;