Resumen
PpIX, a metabolite of 5-aminolevulinic acid (ALA) is necessary for the synthesis of hemoglobin and cytochromes. ALA has had many clinical uses over the last 33 years. Commercial forms of ALA are used every day along with blue light, which enables the fluorescent detection (PDD) of PpIX, which is specifically accumulated in cancer cells, to find bladder cancers and brain cancers. It has been reported that 12 ALA PD, activated by red light from a laser delivered through fiber optics embedded in brain tumors, can completely clear some brain cancers and increase patient survival. The evolution of ALA PDT to ALA SDT now creates the potential for noninvasive ultrasound to activate PpIX to treat brain cancers as well as cancers almost anywhere in the body through the photodynamic effect. The selectivity of ALA for cancer cells and their accumulation of PpIX should make SDT a low risk procedure.