Medical imaging and image formation

Medical imaging involves a good understanding of imaging medium and object, physics of imaging, instrumentation, and often computerized reconstruction and visual display methods. Though there are a number of medical imaging modalities available today involving ionized radiation, nuclear medicine, magnetic resonance, ultrasound, and optical methods, each modality offers a characteristic response to structural or metabolic parameters of tissues and organs of human body. This chapter provides an overview of the principles of medical imaging modalities and a basic linear spatially invariant image formation model used for most common image processing tasks.