All clinical trials have guidelines about who can participate. Before joining a clinical trial, a volunteer must qualify for the study. The factors that allow volunteers to participate in a clinical trial are called "inclusion criteria" and the factors that disallow volunteers from participating are called "exclusion criteria." These criteria generally include age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. To determine if you are eligible, a study doctor or research nurse will review your medical history, diagnosis, pathology results, imaging results (X-ray, CT, PET scans) and current and past medication records.  You may be required to take additional tests to assure you have adequate heart, lung, liver and kidney function.