 Radiologic images are becoming more and more complex, and utilization of radiologic techniques is accelerating. Radiologists and other clinicians are being inundated with radiologic data. Computer aided detection and diagnosis CAD have the potential to improve patient care by increasing sensitivity of diagnostic tests, reducing false positives and improving physician efficiency. Computer aided detection and diagnosis have been under development for many years yet there is still much work to be done to move it from the bench to the bedside. The purpose of this project is to develop and evaluate techniques for CAD using the existing radiologic data available in the Clinical Centers Department of Diagnostic Radiology. Such techniques include but are not limited to automated detection of melanoma, bone metastases and pulmonary emboli. The outcome of this study will be algorithms and software that accurately detect lesions on radiologic studies. 