Local integration of commercially available intra-operative MR-scanner and neurosurgical guidance for metalloporphyrin-guided tumor resection and photodynamic therapy

Abstract

We have locally integrated a commercial intra-operative MR-scanner and neurosurgical guidance system in order to conduct a clinical trial testing for improvement in glioma resection following administration of either of two metalloporphyrin drugs, Xcytrin™ or Lutrin™ (Pharmacyclics Inc., Sunnyvale, CA). Like other porphyrins, these two drugs have been shown to bind preferentially to tumor. The metal in Xcytrin is gadolinium. It should enhance intra-operative MR-scans taken during tumor resection. This would overcome problems of non-specific MR-enhancement caused by intra-operative contrast leakage from the vascular compartment. Both drugs provide fluorescence contrast in the presence of 450 nm wavelength light. Intra-operative fluorescence contrast should facilitate Lutrin photodynamic therapy administration to otherwise invisible glioma residual in the walls of the resection cavity. The metal in Lutrin is Lutetium. When illuminated with 732nm wavelength light, Lutrin causes tumor death via release of singlet oxygen (i.e., photodynamic therapy).