OUTLINE: This is a dose-escalation study. Patients receive etanidazole derivative EF5 IV over 1-2 hours. Approximately 24-48 hours after EF5 treatment, patients undergo surgical resection or biopsy of tumor. Cohorts of 6 patients receive escalating doses of EF5 until the maximum tolerated dose (MTD) or optimal dose is determined. The MTD is defined as the dose preceding that at which 2 of 6 patients experience dose-limiting toxicity. The optimal dose is defined as the dose level at or preceding the MTD and resulting in optimal tumor-to-normal-tissue binding. Patients are followed at 28 days.