RS 240 Lab Final Study Guide

1. What imaging tool is used to adjust brightness and contrast? Window level

2. What 3 controls on the x-ray control panel can be adjusted? Ma, kVp, and mAs

3. What buttons do you press to auto center the tube? ACS Button on top right

4. What does developer do? Turns everything that has been exposed to light black Reacts with sensitized part of the film emulsion

5. What does fixer do? Turns emulsion clear and stops the developer

6. In order to maintain density, if the mA is doubled, what change should be made to exposure time?

kVp should be decreased by 15% 7. What happens to the density as mA is increased?

As mA is increased, the density is increased8. What happens to mA if exposure time remains the same?

If exposure time remains the same and mA is halved then the film will be lighter

9. Why was the step wedge placed perpendicular? Because radiation intensity is greater on the cathode side Anode heel affect

10. If mA is doubled on an exposure with all the other factors remaining the same, what does the image look like?

It will be darker11. What is the primary factor that controls density?

mA12. What does it mean when there are fewer steps visible on a step wedge?

more attenuation13. What is the correct processing sequence in a film processor?

Developer- fixer-wash-dryer14. If the exposure is increased using the 15% rule, will all other factors

remaining the same explain what you would see regarding image quality? Image would be darker

15. Why would the image be darker? Less attenuation More steps= less attenuation

16. What does increased wavelengths mean? Decreased frequency High kVp produces shorter wavelengths

17. What kind of contrast does long scale have? Low contrast

18. What happens when you increase SID?

Increase SID= less distortion because you use more of the horizontal beam

19. What does kVp control? Contrast Beam quality

20. What does mAs control? Quantity Density Patient dose

21. What material would have the most attenuation? Metal** Plastic Fur

22. In a radiograph of the toy due to its composition, what did you see in the image?

High subject contrast 23. When imaging the toy would it be better to use a faster speed to reduce the

radiation exposure? No

24. Magnification factor indicates how much magnification or ________ is demonstrated on a radiograph?

Distortion25. The distance created between the object being radio graphed and the IR is

called? OID

26. Using the MF= image size/object size a magnification factor equal to 1 indicates the true image size?

True (40 SID/40 OID=1) 27. What happens to the magnification when the SID is increased?

When SID is increased then the mag is decreased and the resolution is increased which means there were more circles that were clear

28. What SID has more clear circles 40’ or 72’? 72’

29. Why is 72’ clearer? Less beam divergence

30. What does more beam divergence cause? More distortion and less sharpness

31. What is responsible for producing the image on the film in a cassette equipped with intensifying screens?

Light32. What is responsible for producing the image on the film in a cassette

equipped without intensifying screens? Radiation photons

33. How does relative speed screen relate to mAs?

As the relative speed increases, the amount of exposure required to maintain the same density decreases. The faster the speed of the screen is the more it reduces detail.

34. What factors affect film processing? Time Chemistry Temperature Replenishment

35. What happens as you increase collimation? What happens to the field size and quantity of scatter?

As you increase collimation= field size decrease=scatter decrease

36. What happens to contrast if you decrease collimation?

Decrease scatter=increase contrast37. What happens as kVp increases?

Increase e- flow Decrease wavelength Increase frequency Increase penetration Decrease attenuation Increase scatter Decrease contrast= long scale Decrease pt dose Higher beam quality

38. What happens when you increase OID? INCREASE OID = INCREASE magnification and DECREASE resolution