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Radiology
4-Jolene
Question | Answer |
---|---|
1. What is the term for an energy form that travels the speed of light? | photon |
2. How is Bremsstrahlung radiation produced? | electron speeds close to the nucleus and high quality energy is released |
3. How is characteristic radiation produced? | electron speeds close the inner orbit electrons and high quality energy is released |
4. What type of radiation is x-radiation? | electromagnetic |
5. How fast does x-radiation travel? | speed of light; 186,000 miles per second |
6. List the characteristics and properties of x-radiation. | penetrate matter; produce a latent image; produce fluorescence;produce ionization; travel in straight lines; travel the speed of light; interact with electrons; interact with matter to produce scatter radiation |
7. What can be done to increase the amount of x-radiation emitted from the machine? | increase the mA or the exposure time or both (mAs = mA x exp time in seconds |
8. What can be done to increase the quality of x-radiation emitted from the machine? | increase kVp |
9. How will the radiograph be affected if the mA is decreased? | lighter - lower in density |
10. How will the radiograph be affected if the kVp is increased? | lower contrast (longer gray scale); darker - higher in density |
11. How will the radiograph be affected if the mA is increased? | darker - higher in density |
12. How will the radiograph be affected if the kVp is decreased? | higher contrast (shorter gray scale); lighter - lower in density |
13. What is the purpose of the focusing cup? | direct the electrons towards the focal spot on the target during x-ray production |
14. Where do x-rays originate? | the focal spot of the target on the anode side of the x-ray tube located in the tubehead |
15. What is the purpose of the filter? | remove long wavelength x-rays of low penetrating ability |
16. What is the purpose for the collimator? | control the size and shape of the x-ray beam |
17. What exposure setting determines the wavelength of the x-ray? | kVp |
18. What quality of the x-ray is changed when the wavelength is changed? | penetrating ability (wavelength) |
19. What type of collimator is recommended by the ADA? | Rectangular |
20. What is stated by the inverse square law? | intensity of the x-ray beam decreases inversely proportional to the square of the distance from the source (as the beam gets farther from the tube, it gets larger AND less concentrated) |
21. What is meant by short scale contrast? | higher contrast radiograph with fewer shades of gray evident |
22. What is meant by long scale contrast? | lower contrast radiograph with more shades of gray evident |
23. What exposure setting affects the contrast scale? | kilovoltage - kVp |
24. What quality of the radiographic image will be affected by patient movement and film movement? | sharpness aka definition |
25. What is the purpose for the filament? | form electron cloud when machine is turned *on*, making available electrons for x-ray production |
26. What is the first thing that should be done if the x-ray machine malfunctions? | turn it off |
27. How is the machine tested for tubehead drift? | move the tubehead into various postions and see if it remains or drifts |
28. What is recommended if the tubehead drifts? | have it repaired; in the meantime, do not use it |