Fluorescence-guided resection of intracranial VX2 tumor in a preclinical model using 5-aminolevulinic acid (ALA): Preliminary results

Fluorescence-guided brain tumor resection may help the neurosurgeon to identify tumor margins that merge imperceptibly into the normal brain tissue and are difficult to identify under white light illumination even using an operating microscope. We compared the amount of residual tumor after white light resection using an operating microscope versus that after fluorescence-guided resection of an intracranial VX2 tumor in a preclinical model using our previously developed co-axial fluorescence imaging and spectroscopy system, exciting and detecting PpIX fluorescence at 405 nm and 635 nm respectively. Preliminary results: No fluorescence was present in 3 non-tumor-bearing animals. Fluorescence was present in all 15 tumor-bearing animals after white light resection was completed. To date in 4 rabbits, a decrease in residual tumor was found when using additional fluorescence guided resection compared to white light resection only. Conclusions: ALA induced PpIX fluorescence detects tumor margins not seen under an operation rnicroscope using white light. Using fluorescence imaging to guide tumor resection resulted in a 3-fold decrease in the amount of residual tumor. However, these preliminary results indicate that also an additional amount of normal brain is resected, which will be further investigated.