Evaluation of Ascorbate-Meglumine Therapeutic for SRS

Inclusion Criteria: * Primary cancer diagnosis with newly diagnosed brain metastases * Diagnostic MRI demonstrates the presence of 1 to 3 intact (not previously irradiated or resected) brain metastases. * Maximum tumor diameter ≤ 2.5 cm for the largest lesion determined during the planning MRI * Plan of care must include Stereotactic Radiosurgery (SRS) * SRS treatment plan must be delivered as a single RT fraction * Age 18 years and older * Life expectancy of at least 3 months * GPA score 0.5 or greater * Capable of providing written informed consent to participate in the study Exclusion Criteria: * Primary lesion with radiosensitive histology (i.e., small cell carcinoma, germ-cell tumors, lymphoma, leukemia, and multiple myeloma) * Metastases in the brain stem, pons or medulla or within 3 mm of the optic apparatus (such that some portion of the optic nerve or chiasm would receive a radiation dose \> 10 Gy SRS in one single fraction) * Previous whole-brain radiation (previous SRS to or resection of other brain lesions is permitted if more than 3 months prior to the date of enrollment on this protocol) * Pregnancy * History or manifestation of glucose-6-phosphate dehydrogenase (G6PD) enzyme deficiency * History of oxalate kidney stones * History of iron overload or hemochromatosis * History of allergy to ascorbic acid * Anuria, dehydration, serum albumin \<3.0 g/dL, severe pulmonary congestion or pulmonary edema or fixed low cardiac input since all are conditions for which osmotic diuresis are contraindicated . * Subjects who are on the following drugs and cannot have a drug substitution: flecainide, methadone, amphetamines, quinidine, and chlorpropamide. * Subjects who are on strong inducers, inhibitors or substrates of CYP within 3 days of planned administration of study ascorbate-meglumine. * Subjects for which MRI is contra-indicated (for example a pacemaker/recent surgery with orthopedic prosthesis)