OBJECTIVES: I. Determine the maximum tolerated dose of gadolinium texaphyrin as a tumor retained contrast agent in MRI guided neurosurgery in patients with radiological diagnosis of high grade glioma. I. Determine the intratumoral pharmacology and quantitative pharmacokinetics of gadolinium texaphyrin using MRI imaging in these patients. II. Develop a scale that will relate MRI signal characteristics from intratumoral gadolinium texaphyrin with absolute intratumoral levels of gadolinium texaphyrin in these patients. III. Investigate the distribution of gadolinium texaphyrin in high grade gliomas in comparison with biologically active tumor as delineated by elevated choline-containing material detected by proton magnetic resonance spectroscopic imaging.