 - Arm B Large brain metastases: Pathological diagnosis of malignancy is required, from either the primary tumor or a metastasis. A radiological diagnosis CT or MRI scan of one of more brain metastases is required. At least one of the brain metastases to be treated as part of this study must be 2.5cm or larger in maximal diameter. The brain metastasises to be treated may not be more than 4cm in maximal diameter, as assessed by CT or MRI scan. The brain metastasis may either be un-resected or partially resected, provided that the target lesion which may include a resection cavity remains between 2.5 and 4cm in diameter, as defined in section 6. Whole brain radiation therapy may or may-not have been delivered prior to entering this protocol. 