CT screening has been associated with a high rate of falsely positive tests which may result in unneeded treatment. For each true positive scan there have been as many as 19 falsely positives scans. When screening is done in the context of a process of diagnostic tests, false positives have been reduced to approximately 12%. Other concerns include radiation exposure and the cost of testing along with the follow up of tests. Research has not found two other clinically available tests – sputum cytology or chest radiograph (CXR) screening tests — to reduce the overall number of people who die from lung cancer.