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RADT 456 Unit 3
ARRT registry review Unit 3: Image Acquisition and Evaluation
| Question | Answer |
|---|---|
| 1. During film-screen imaging, when is the manifest image formed? | in the developer solution |
| 2. What is the component of a CR image plate that records the radiologic image? | photostimulable phosphor |
| 3. The term windowing describes the practice of _____ | changing the image contrast and / or density |
| 4. What can foreshortening be caused by? | the radiographic object being placed at an angle to the IR |
| 5. What is the purpose of the automatic processor's transport system? | move the film and change its direction |
| 6. What causes crescent-shaped artifacts on processed x-ray film? | acute bending of the film before or after exposure |
| 7. Misalignment of the tube-part-IR relationship results in______ | shape distortion |
| 8. Using a short SID with a large IR is likely to____ | increase the anode heel effect |
| 9. When intensifying screen increases, what happens to radiographic density? | increases |
| 10. How can you improve spatial resolution but still use the same FOV? | use a larger matrix |
| 11. What is the absorption of useful radiation by a grid called? | grid cutoff |
| 12. When is focal-spot blur at its greatest? | toward the cathode end of the x-ray beam |
| 13. What is it called when the x-ray photon intensity is reduced as the photon passes through material? | attenuation |
| 14. What is the density of an unexposed and processed film? | 0.1 |
| 15. What device is used to overcome severe variation in patient anatomy or tissue density, providing more uniform radiographic density? | compensating filter |
| 16. What test is performed to check the correctness of the developing parameters? | sensitometry |
| 17. What is the purpose of the thin layer of lead that is often located behind the rear intensifying screen in an IR? | prevent scattered radiation fog |
| 18. What will result if developer replenishment is inadequate? | images with excessively low contrast |
| 19. What can be used to determine the sensitivity of a particular film emulsion? | sensitometric curve |
| 20. What is a wire-mesh test performed to evaluate? | screen contact |
| 21. What accessory is used to measure the thickness of body parts in order to determine optimal selection of exposure factors? | caliper |
| 22. What is a focal-spot size of 0.3mm or smaller essential for? | magnification radiography |
| 23. What is the device that is used to give film emulsion a predetermined exposure in order to test its response to processing called? | sensitometer |
| 24. What is the relationship between the height of a grid's lead strips and the distance between them referred to? | grid ratio |
| 25. What material is film base currently made of? | polyester |
| 26. What happens to the image when a slow screen-film system is used with a fast screen-film AEC system? | the images are too light |
| 27. What effect will a stained intensifying screen have on the finished radiograph? | decreased density |
| 28. What will boxes of film stored in a too warm an area be subject to? | film fog |
| 29. What term is used to describe unsharp edges of tiny radiographic details? | blurr |
| 30. What chemical is used in the production of radiographic film emulsion? | silver halide |