Rad 113 Lecture Worksheets 1 and 2

1. The difference in gray scale values between adjacent structures on a radiograph is called what?

Contrast

2. True or False: Scatter radiographic fog reduces contrast.

True

3. Define digital image brightness.

Intensity of light in individual pixels as displayed on the monitor.

4. What is the relationship between DI brightness and mAs?

Brightness is unrelated to mAs; auto rescaling controls brightness as determined by the LUT.

5. How does the use of contrast media affect the image?

Increases subject contrast.

6. Which of the following factors affects subject contrast? A. kVp B. mAs

A. kVp

7. A radiograph that exhibits long-scale contrast is one with: A. Many shades of gray having minimal differences B. Few shades of gray having minimal differences C. Determine optical density D. Control quantum mottle

A. Many shades of gray having minimal differences.

8. The function of contrast is to: A. Control the sharpness of detail B. Make detail visible C. Determine optical density D. Control quantum mottle

B. Make detail visible.

9. What parameter sets the range of gray scale values (pixel brightness) visible in the displayed image?

Window width

10. Subject contrast is enhanced with the use of positive contrast media because: A. Absorption unsharpness is reduced B. Geometric unsharpness is reduced C. Photoelectric interactions are increased D. Compton effect is increased

C. Photoelectric interactions are increased.

11. Which exposure factors result in the greatest radiographic exposure if all other factors remain constant? A. 100 mA, 750 msec, 90 cm SID B. 200 mA, 500 msec, 90 cm SID C. 300 mA, 300 msec, 100 cm SID D. 400 mA, 200 msec, 100 cm SID

B. 200 mA, 500 msec, 90 cm SID

12. For every how many cm of part thickness should the radiographer adjust mAs by a factor of 2? A. 2–3 B. 4–5 C. 6–7 D. 8–9

B. 4–5 cm

13. If changing from 100 mA and 1.0 second to 100 mA and 0.5 second, what happens to IR exposure? A. Increase B. Decrease C. No change

B. Decrease

14. If SID changes from 100 cm to 120 cm, what happens to IR exposure? A. Increase B. Decrease C. No change

B. Decrease

15. If kVp increases from 65 to 75 kVp, what happens to IR exposure? A. Increase B. Decrease C. No change

A. Increase

16. If the grid changes from 8:1 to 12:1, what happens to IR exposure? A. Increase B. Decrease C. No change

B. Decrease

17. Which change would produce a digital image with decreased brightness? A. Increased mAs B. Decreased kVp C. Increased patient thickness D. None of the answers

D. None of the answers

18. An image with low contrast appears: A. Black and white B. Very gray

B. Very gray

19. With all other factors remaining the same, which body habitus requires the highest exposure factors? A. Asthenic B. Hyposthenic C. Sthenic D. Hypersthenic

D. Hypersthenic

20. Generally speaking, what technical exposure factor change do additive pathologic conditions require? A. Increased focal spot size B. Increased mA C. Increased kVp D. Increased SID

C. Increased kVp

21. Define contrast resolution.

Ability of a system to distinguish between structures having similar attenuation and therefore similar shades of gray.1. The Inverse Square Law states that: A. The size of the x-ray field becomes smaller as distance increases B. The intensity of radiation varies inversely as the square of the SID C. The intensity of radiation varies inversely as the square of the OID D. Field coverage increases as distance decreases

2. If the SID is halved, and all other factors remain constant, to maintain radiographic exposure you would: A. Use 1/2 the original exposure factors B. Use 1/4 the original exposure factors C. Double the original exposure factors D. Quadruple the original exposure factors

B. Use 1/4 the original exposure factors.

3. To increase kVp from 70 to 80 generally requires what change in mAs to maintain radiographic exposure? A. 2 times the mAs B. 1/2 the mAs C. 1/4 the mAs

B. 1/2 the mAs.

4. A technique of 100 mA, 0.5 sec at 80 kVp could be converted to 50 mA, 2 sec at what kVp with the same resulting radiographic exposure? A. 60 kV B. 68 kV C. 92 kV D. 105 kV

B. 68 kV.

5. At 10 inches, the intensity is 112 mR. What is the intensity at 40 inches? A. 7 mR B. 28 mR C. 56 mR D. 448 mR

A. 7 mR.

6. A portable chest radiograph was performed using 4 mAs at 90 kVp and a distance of 48 inches. What new mAs is needed to maintain exposure at 72 inches SID? A. 1.7 mAs B. 2.6 mAs C. 6 mAs D. 9 mAs

D. 9 mAs.

7. When kVp is increased with a compensating reduction in mAs by the 15% rule, what is reduced? A. Scatter radiation exposing the IR B. Exposure C. Exit radiation D. Patient dose

D. Patient dose.

8. Which lumbar spine exposure factors would result in the greatest radiation exposure to the patient? A. 200 mAs, 70 kVp B. 100 mAs, 80 kVp C. 50 mAs, 95 kVp D. 25 mAs, 110 kVp

A. 200 mAs, 70 kVp.

9. Which lumbar spine exposure factors would produce the greatest amount of scatter radiation? A. 200 mAs, 70 kVp B. 100 mAs, 80 kVp C. 50 mAs, 95 kVp D. 25 mAs, 110 kVp

D. 25 mAs, 110 kVp.

10. Exit radiation is composed of photons that: A. Have undergone photoelectric interactions B. Are absorbed in the patient C. Did not interact with the patient plus those that have undergone Compton interactions D. Only are non-interacting transmitted photons

C. Did not interact with the patient plus those that have undergone Compton interactions.

11. Which factor affects the level of scattered radiation and is not easily controlled by the radiologic technologist? A. Inherent filtration B. Added filtration C. Patient thickness D. Field size

C. Patient thickness.

12. As field size is decreased, scatter radiation: A. Is removed B. Is increased C. Remains constant D. Is reduced

D. Is reduced.

13. Which factors influencing scatter radiation production are generally under the control of the technologist? A. kVp B. Field size C. Both of the above D. Neither of the above

C. Both of the above.

14. Which of the following is NOT a device designed to reduce scatter radiation reaching the IR? A. Star test pattern B. Compression device C. Variable aperture collimator D. Aperture diaphragm

A. Star test pattern.

15. Scatter radiation chiefly influences radiographic quality by reducing: A. Density B. Contrast C. Sharpness D. Distortion

B. Contrast.

16. When making a significant increase in collimation, what should be changed to maintain radiographic exposure? A. Increase kV B. Decrease kV C. Increase mAs D. Decrease mAs

C. Increase mAs.

17. As kVp increases from 70 to 80: 1. Less scatter radiation is produced 2. More scatter radiation is produced 3. Radiographic contrast increases 4. Radiographic contrast decreases. A. 1 and 3 B. 2 and 3 C. 1 and 4 D. 2 and 4

D. 2 and 4.

18. As the field size of the x-ray beam increases, what increases? A. Scatter radiation B. Patient exposure C. Radiographic contrast D. Two of the above

D. Two of the above (scatter radiation and patient exposure).

19. In radiography, using low kVp has what effects? 1. High amount of photoelectric interactions 2. Low amount of scatter radiation 3. High amount of scattered x-ray photons 4. High amount of Compton interactions. A. 1 and 2 B. 1 and 3 C. 3 and 4 D. 2 and 4

A. 1 and 2.

20. The use of higher kVp is desirable so that what will be at a lower level? A. Scatter radiation B. Compton effect C. Patient dose

C. Patient dose.

21. X-ray beam restriction to the area of interest is principally required to reduce: A. Scatter radiation and patient dose B. Radiographic contrast C. Exposure factors

A. Scatter radiation and patient dose.

22. Which of the following is NOT a beam-restricting device? A. Aperture diaphragm B. PBL device C. Added filtration D. Cylinder cone

C. Added filtration.

23. The field size should never exceed the size of the: A. Primary radiation barrier B. Secondary radiation barrier C. Image receptor D. None of the above

C. Image receptor.

24. True or False: In a light-localizing variable aperture collimator, periodic checks of x-ray beam and light field coincidence are necessary.

True.

25. Off-focus radiation: A. Consists of scattered electrons B. Is useful for image production C. Results when projectile electrons do not strike the focal spot of the anode D. Consists of electrons as well as x-rays

C. Results when projectile electrons do not strike the focal spot of the anode.

26. Off-focus radiation: A. Increases penumbra and degrades the radiographic image B. Reduces patient dose C. Improves image contrast D. Originates from outside the x-ray tube

A. Increases penumbra and degrades the radiographic image.

27. Which device is designed to limit off-focus radiation? A. Fixed aperture circular diaphragms B. Fixed aperture rectangular diaphragms C. First-stage shutters of a variable aperture diaphragm D. Second-stage shutters of a variable aperture diaphragm

C. First-stage shutters of a variable aperture diaphragm.

28. The principal reason for using a grid is to: A. Reduce patient dose B. Remove remnant radiation C. Enhance differential absorption D. Increase radiographic contrast

D. Increase radiographic contrast.

29. Which of the following will NOT enhance radiographic contrast? A. Decrease in kVp B. Use of a grid C. Use of a small focal spot D. Collimating the x-ray beam

C. Use of a small focal spot.

30. The single grid characteristic grids are most often selected for is: A. Grid ratio B. Grid frequency C. Grid height D. Grid weight

A. Grid ratio.

31. In the design of a radiographic grid, the: A. Interspace material is radiopaque B. Interspace material is radiolucent C. Grid strips are radiotransparent D. Grid strips are radiolucent

B. Interspace material is radiolucent.

32. X-ray grids are principally effective in attenuating: A. Photoelectrons B. X-rays following photoelectric interactions C. X-rays following Compton interactions D. All exit radiation

C. X-rays following Compton interactions.

33. If the interspace dimension is constant, increasing the grid ratio will: A. Make the grid strips higher B. Make the grid lighter C. Require less grid strip material D. Require less interspace material

A. Make the grid strips higher.

34. As grid frequency increases: A. The number of grid strips per centimeter decreases B. Patient dose is reduced C. Interspace width becomes thinner if grid strip width remains constant D. Grid ratio is reduced if grid thickness remains constant

C. Interspace width becomes thinner if grid strip width remains constant.

35. Grids with a high ratio: A. Are more effective than those with a low ratio B. Are easier to manufacture than those with a low ratio C. Can be created by increasing interspace width D. Can be created by increasing grid strip width

A. Are more effective than those with a low ratio.

36. The efficiency of a grid for reducing scatter radiation is related principally to the: A. Grid ratio B. Grid radius C. Grid frequency D. Grid mass

A. Grid ratio.

37. Radiographic grids must be placed: A. Between the source and patient B. Between the patient and image receptor

B. Between the patient and image receptor.

38. The contrast improvement factor is defined as the radiographic contrast obtained: A. At a density of 1.0 B. With a screen compared to without one C. With a grid compared to without one D. Without a grid compared to with one

C. With a grid compared to without one.

39. As the ratio of a grid increases, what also increases? A. System speed B. Intensification factor C. Contrast improvement factor D. Thickness of interspace material

C. Contrast improvement factor.

40. The undesirable absorption of x-rays by a grid is termed: A. Primary beam scatter B. Grid factor C. Grid failure D. Grid cut-off

D. Grid cut-off.

41. Which factor does NOT affect the percentage of scatter radiation reaching the IR? A. Patient thickness B. Grid ratio C. kVp D. mAs

D. mAs.

42. Which of the following is NOT a grid positioning error? A. Off-focus grid B. Off-level grid C. Off-center grid D. Air gap technique

D. Air gap technique.

43. Which is a characteristic of parallel grids compared with focused grids? A. Lower grid ratios B. Lower grid frequencies C. High grid cut-off D. Increased patient dose

C. High grid cut-off.

44. Radiographic grids: A. Usually have contrast improvement factors from 1.5 to 3.5 B. Usually have grid ratios between 5:1 and 16:1 C. Usually require an increase in exposure and patient dose from 3 to 6 times a non-grid exposure D. Require that the x-ray beam can only be angled in a direction with the lead strips E. All of the above

E. All of the above.

45. A hip radiograph uses 100 mAs with a 10:1 grid. What new mAs is needed for a non-grid exposure in the OR?

100 ÷ 5 = 20 mAs.

46. A preliminary AP cervical spine radiograph uses 6 mAs non-grid. What mAs is needed for a repeat AP cervical spine view using a 12:1 grid?

6 × 5 = 30 mAs.

47. A lateral skull radiograph uses 30 mAs with a 6:1 grid. What new mAs is needed with a 12:1 grid?

30 × (5 ÷ 3) = 50 mAs.

48. An AP femur radiograph uses 24 mAs with a 5:1 grid. What new mAs is needed with a 10:1 grid?

24 × (5 ÷ 2) = 60 mAs.

49. An abdomen radiograph uses 80 mAs with a 12:1 grid. What new mAs is needed with a 6:1 grid?

80 × (3 ÷ 5) = 48 mAs.

50. A non-grid exposure requires 10 mAs, while the same exposure with a Bucky grid requires 40 mAs. What is the grid ratio?

8:1 grid ratio.