This is an open-label Phase II study of postoperative radiation therapy followed by Iodine-125 radiolabeled anti-epidermal-growth-factor-receptor monoclonal antibody (125I-MAB 425) derived from cell cultures for high grade malignant gliomas. Each subject will receive postoperative radiation therapy followed by 6.4 mg of 50 mCi labeled 125I-MAB 425 by injection. This dosing regimen will be given three times generally within a two-week period (days one, eight and 15 of therapy) for a total dose of 19.2 mg of 150 mCi labeled 125I-MAB 425 for each course of therapy. The main objective of this study is to determine if the addition of 125I-MAB 425 to postoperative radiotherapy, with or without change, prolongs absolute survival compared to historical control (postoperative radiation therapy alone) in subjects with histologically proven high grade gliomas. The primary efficacy variable is absolute survival and the secondary target variable will be time to progression of the tumor. Multiple courses will be considered based on the subject's clinical status.