We are developing computer-aided diagnosis systems based on image processing technologies such as CT(Computed Tomography), MR(Magnetic Resonance), CR(Computed Radiology), and microscope imaging. To develop the the CAD technologies, we propose some image registration algorithms, and detection of lesions using feature analysis or deep learning technique. Also we develop some segmentation methods for detection of multiple human organs. As a result, radiologists can easily detect abnormalities and treatment of diseases.