1. Digital radiography is a modern imaging technique that uses digital technology to capture and store X-ray images. Instead of using traditional film, digital radiography uses digital detectors to capture the X-ray image, which can then be viewed and manipulated on a computer.
2. Ehsan Samei has proposed a descriptive approach to various digital radiography (DR) imaging techniques. This approach includes factors such as detector technology, dose efficiency, spatial resolution, dynamic range, and image noise.
3. A flat panel detector (FPD) is a type of digital detector used in digital radiography. It consists of a thin, flat panel that contains an array of X-ray sensors. These sensors convert X-ray photons into electrical signals, which are then processed to create the digital image.
4. Direct conversion is a process used in some digital detectors, such as amorphous selenium detectors. In direct conversion, X-ray photons are converted directly into electrical charges by a photoconductive material. These charges are then read out and processed to create the digital image.
5. Indirect conversion is another process used in digital detectors, such as amorphous silicon detectors. In indirect conversion, X-ray photons are first converted into light photons by a scintillator material. These light photons are then converted into electrical charges by a photosensitive material, which are then read out and processed to create the digital image.
6. An amorphous selenium detector is a type of direct conversion digital detector. It consists of a layer of amorphous selenium, which is a photoconductive material. When X-ray photons interact with the selenium layer, they generate electrical charges proportional to the X-ray intensity. These charges are then read out and processed to create the digital image.
7. An amorphous silicon detector is a type of indirect conversion digital detector. It consists of a layer of amorphous silicon, which acts as a photosensitive material. X-ray photons are first converted into light photons by a scintillator material, and these light photons then interact with the silicon layer to generate electrical charges. These charges are read out and processed to create the digital image.
8. A charge-coupled device (CCD) is a type of digital detector that is commonly used in digital cameras and some medical imaging systems. It consists of an array of light-sensitive diodes that convert light photons into electrical charges. These charges are then transferred and read out to create the digital image.
9. The sensitivity of a charge-coupled device refers to its ability to detect and convert light photons into electrical charges. The dynamic range, on the other hand, refers to the range of light intensities that the CCD can accurately detect and represent in the digital image.
10. Detective Quantity Efficiency (DQE) is a measure of the ability of a digital imaging system to accurately capture and represent the X-ray signal. It takes into account factors such as the sensitivity of the detector, the noise level, and the system's ability to preserve image details.
11. DQE is crucial in digital imaging as it determines the overall image quality and the system's ability to detect and accurately represent different tissue structures and pathologies. A higher DQE indicates a more efficient and effective imaging system.
12. Compared to a screen-film system, computed radiography (CR) generally has a higher DQE. This is because CR uses digital detectors that can capture a wider range of X-ray signal intensities and convert them into a digital image with minimal loss of information.
13. Spatial resolution in digital radiography refers to the ability of the system to accurately represent small details and structures in the image. Factors that affect spatial resolution include the pixel size of the detector, the focal spot size, and the geometric properties of the X-ray system.
14. Dynamic range in digital radiography refers to the range of X-ray signal intensities that the system can accurately detect and represent in the digital image. A larger dynamic range allows for the representation of a wider range of tissue densities and helps preserve image details in both low and high-density areas.
15. Latitude in digital radiography refers to the range of exposure values that can be captured and still produce a diagnostically useful image. A system with a wider latitude can handle a larger range of exposure values without losing image quality or diagnostic information.
