CH 9 Key Terms

123456789101112131415161718192021222324252627282930313233
Across
  1. 3. A method of describing the strength of the radiation exposure compared with the amount of noise apparent in a digital image.
  2. 7. When the image receptor is extremely overexposed, cannot be properly processed, and the quality is severely degraded.
  3. 10. An increase in the image size of an object compared with its true, or actual, size; also known as size distortion.
  4. 12. The range of exposure intensities that an image receptor can respond to and acquire image data.
  5. 15. Tissues that attenuate the x-ray beam very differently.
  6. 16. Tissues that attenuate the x-ray beam similarly.
  7. 17. Results from the radiographic misrepresentation of either the size (magnification) or shape of the anatomic part.
  8. 23. differences in the brightness levels to differentiate among tissues.
  9. 25. A measure of the ability of the system to preserve signal contrast (display the contrast of anatomic objects varying in size), and the value will be between 0 (no difference in brightness levels) and 1.0 (maximum difference in brightness levels).
  10. 26. The amount of luminance (light emission) of a display monitor.
  11. 28. Also called number of bits (e.g., 12, 14, or 16), it affects the number of shades of gray available for image display.
  12. 30. Used to describe the ability of the imaging system to distinguish between small objects that attenuate the x-ray beam similarly in digital imaging
  13. 31. The pixel spacing or distance measured from the center of a pixel to an adjacent pixel.
  14. 32. The ability of the imaging system to resolve or distinguish between two adjacent structures and can be expressed in the unit of line pairs per millimeter (Lp/mm).
  15. 33. A measurement of the efficiency of an image receptor in converting the x-ray exposure it receives to a quality radiographic image.
Down
  1. 1. A term used to evaluate accuracy of the anatomic structural lines.
  2. 2. The accuracy of the structural lines is achieved by maximizing the amount of spatial resolution and minimizing the amount of distortion.
  3. 4. Refers to the absorption characteristics of the anatomic tissue radiographed along with the quality of the x-ray beam.
  4. 5. Number of pixels per unit area.
  5. 6. Factors that make the anatomic structures visible and include the brightness and contrast of the image.
  6. 8. Refers to an increase in the object’s image size compared with its true, or actual, size; also known as magnification.
  7. 9. The dimensions of an anatomic area displayed on the monitor.
  8. 11. A control that adjusts the radiographic contrast on the digital image. In CT, it adjusts how many CT numbers are visible in the image.
  9. 13. Any unwanted image on a radiographic image.
  10. 14. Refers to images of objects that appear longer than the true objects.
  11. 18. Provides a numeric value indicating the level of radiation exposure to the digital image receptor.
  12. 19. A method of describing the contrast resolution compared with the amount of noise apparent in a digital image.
  13. 20. Refers to images that appear shorter than the true objects.
  14. 21. The number of different shades of gray that can be stored and displayed by a computer system in digital imaging
  15. 22. Sets the midpoint of the range of brightness visible in the digital image. In CT, the WL determines the midpoint of the range of CT numbers to be displayed.
  16. 24. Differences in the brightness levels to differentiate among the anatomic tissues.
  17. 27. Visible as brightness fluctuations on the image. Caused by too few photons reaching the image receptor to form the image.
  18. 29. Combination of rows and columns (array) of pixels that make up a digital image.