Study of Low Dose Whole Brain Irradiation in the Treatment of Alzheimer's Disease

This study is designed to assess the safety and toxicity/adverse events associated with the use of low dose fractionated whole brain irradiation in those patients who have been diagnosed with probable Alzheimer's disease according to the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria. As a secondary goal it will establish whether or not the intervention with low dose whole brain irradiation might change the recognized progression of Alzheimer's Disease. The investigators will also collect information from the florbetaben F 18 Injection (AMYVID®) positron emission tomography (PET) Scans to determine if there is any correlation between neurocognitive/quality of life scores and changes in amyloid plaque size, number and location.