Aminolevulinic acid (ALA)-protoporphyrin IX fluorescence guided tumour resection. Part 2: theoretical, biochemical and practical aspects.

The importance of the extent of resection for gliomas, and the utility of aminolevulinic acid (ALA) and protoporphyrin IX fluorescence in increasing the extent of resection, has become increasingly evident over the past decade. This review continues from Part 1 and focuses on the biochemical mechanisms by which ALA ingestion leads to tumour fluorescence, and discusses practicalities of the equipment and techniques needed to introduce ALA and fluorescence guided resection into neurosurgical practice.