![]() The EIDs, however, measure the energy-integrated signals of x-ray photons, thus losing all of the energy-dependent information. Therefore, the transmitted x-ray spectra carry information about different tissue types (see Fig. These limitations result from or are made worse by the energy integrating detectors (EIDs) used in CT scanners and XR systems.įactors influencing the x-ray linear attenuation coefficients include the chemical composition and mass density of the object, and the energy of the x-ray photons. However, there are four major limitations to current CT and XR technologies: (1) the contrast between different soft tissues is often insufficient (2) images are not tissue-type specific (different tissue types can appear with similar pixel values) (3) “CT scanning is a relatively high-dose procedure ” 1 and (4) gray-scale pixel values of CT images, which should be linear attenuation coefficients, are not quantitative but qualitative (see Sec. Multislice x-ray computed tomography (CT or multidetector-row CT) scanners provide three-dimensional images of the linear attenuation coefficient distribution within a patient, accurately delineating organs and tissues. X-ray (XR) systems provide two-dimensional images of the transmitted x-ray intensities. Transmitted and detected x-ray beams generate a snapshot projection image, a series of projection images, or cross-sectional tomographic images. ![]() They are helping radiologists and physicians to detect and characterize disease processes of the skeletal system, soft tissue, and their functionality. ![]() Röntgen, x-rays have been playing a critical role in medical imaging. Since their discovery in 1895 by Wilhelm C. ![]()
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