Medical imaging refers to the technology and processing process of obtaining the internal tissue image of human body or a certain part of human body in a non-invasive way for medical treatment or medical research, and it is the reasoning calculus of inverse problem. 1895, the german physicist roentgen discovered x-rays, which were quickly used to examine human diseases, and thus formed diagnostic radiology. Over the years, CT, MRI, ultrasound and radionuclide imaging equipment have been continuously improved and perfected, and inspection techniques and methods have been constantly innovated. Imaging diagnosis has developed from relying solely on morphological changes to a comprehensive diagnostic system integrating morphological, functional and metabolic changes. At the same time, some new technologies, such as magnetic source imaging of the heart and brain, and new branches of disciplines, such as molecular imaging, are constantly emerging, and the scope of imaging diagnostics is still developing and expanding.