 The purpose of this study is to evaluate low oxygen areas called hypoxia within the tumor. These low oxygen areas are thought to be the reason why tumors are more resistant to radiation treatment. A tracer is an extremely small quantity of a substance. Tracer to which radioactivity has been attached may be used to trace events in the body. A tracer called iodo-azomycin galactopyranoside or IAZGP appears to be able to detect low oxygen areas within tumor. 