The first 12 patients accrued to the study undergo stereotactic placement of 2 catheters within the contrast-enhancing tumor on day 0. These patients then receive an imaging dose of ^131I MOAB TNT-1/B interstitially over approximately 25 hours on day 1 followed by dosimetry, biodistribution evaluations, and whole body imaging over an 8-10 day period. Beginning at least 2 weeks, but no more than 4 weeks later, all patients undergo catheter placement as above. One day later, patients receive a therapeutic dose of ^131I MOAB TNT-1/B interstitially over approximately 25 hours.