ABSTRACT
Planar x-ray imaging is considered the historically first medical imaging modality. The x-ray projection radiography is the historically oldest medical imaging modality—its history goes back to Roentgen’s discovery of x-rays in the last decade of the 19th century. The image is formed of intensity values of the x-rays modified by passing through the imaged object. Every pixel in the resulting image ideally represents the intensity of the incident x-ray that carries the information on the total attenuation along the respective ray. In reality, x-ray imaging is more complicated than it originally would seem. X-rays are produced in x-ray tubes as a result of the partial conversion of the energy of highly accelerated electrons into x-rays. The incident x-ray beam interacts with the material of imaged objects in basically three ways: photoelectric effect, coherent Rayleigh scattering, and incoherent Compton scattering. Historically, the x-radiation passing the object was visualized by a luminescent screen converting the x-rays into visible light.
