Mosby Chap 7 Test 1, Q 1 - 74

Front 1

1. Attenuation

Back 1

Describes changes in the xray beam as it travels through the patient.

Front 2

2. Which photon-tissue interaction makes radiography possible because of its creation of contrast

Back 2

Photoelectric

Front 3

3. Which photon tissue interaction produces radiation that may expose others in the room during fluoscopy

Back 3

Compton

Front 4

The traditional unit of absorbed dose it the

Back 4

RAD

Front 5

The traditional unit of activity is the

Back 5

Curie

Front 6

6. Measurement of positive and negative particles created when radiation ionizes atoms in the air helps define the

Back 6

Roentgen

Front 7

7. Linear Energy transfer

Back 7

varies for different types of radiation

Front 8

8. The unit of curie would be used for what imaging modality?

Back 8

Nuclear medicine

Front 9

9. Graphs that demonstrate the relationship between radiation received and the organism's response are called

Back 9

Dose response curves

Front 10

10. Medical x-rays are an example of

Back 10

Artifically produced radiation

Front 11

11. Cataractogenesis does NOT occur at low levels of radiation exposure. Therefore it is best expressed by which dose response relationship?

Back 11

Threshold

Front 12

12. Increased dose equals increased probability of effects best describes

Back 12

Stochastic effects

Front 13

13. The cumulative occupational exposure for a 22 year old radioagraphyer is

Back 13

22 rem

Front 14

14. The annual effective dose limit for the general public, assuming frequent exposure is

Back 14

0.1 rem

Front 15

15. The secondary protective barrier used in room shielding must be at least how thick?

Back 15

1/32 inch Pb equivalent

Front 16

16. The intensity of the scattered beam is 1/1000 the intensity of the primary beam at a _______ angle 1 meter from the patient.

Back 16

90 degrees

Front 17

17. If the radiation dose 6 feet from the xray table is 5 R, what is the dose at a distance of 3 feet?

Back 17

20 R

Front 18

18. The minimum source-to-skin distance for fixed fluoroscopes is

Back 18

15 inches

Front 19

19. The use of gonadal shielding on female patients may reduce gonad dose by up to:

Back 19

50%

Front 20

20. Cells that are oxygenated are more susceptible to radiation damage. This describes

Back 20

Oxygenation enhancement ratio

Front 21

21. The blood count is depressed following a whole body dose equivalent of at least how many rads?

Back 21

25

Front 22

22. Highly reactive ions that have unpaired electrons in the outer shell are called?

Back 22

Free radicals

Front 23

23. The master molecule that directs cell activities is

Back 23

DNA

Front 24

24. The process of somatic cell division is

Back 24

Mitosis

Front 25

25. The most common effect from exposure to ionizing radtion is

Back 25

nothing

Front 26

26. Most radiation-induced damage to cells occurs

Back 26

at doses of radiation much higher than that ued in radiography

Front 27

27. Radiation doses up to _____ are considered low risk to the embryo-fetus.

Back 27

15 - 20 rads

Front 28

28. A concept of radiologic practice that encourages radiation users to adopt measures that keep the dose to the patient and themselves at the minimum.

Back 28

ALARA

Front 29

29. Which of the following is(are) relatively insensitive to radiation?

Back 29

Nerve tissue

Front 30

30. Somatic effects of radiation are caused when

Back 30

a large dose of high-LET radiation is received by a large area of the body.

Front 31

31. The best way to keep radiation dose to the patient low is

Back 31

Avoiding repeat exposures

Front 32

32. Xrays may remove electrons from atoms in the body by a process called

Back 32

Ionization

Front 33

33. Ionization may cause

Back 33

Unstable atoms

Front 34

34. Cell damage may be exhibited as

Back 34

loss of function or abnormal function

Front 35

35. Damage to the cell being irradiated is called ...

Back 35

Somatic

Front 36

36. Radiation effects that show up in the next generation are called ...

Back 36

Genetic

Front 37

37. Radiation that is contained in the environment is called

Back 37

Natural Background

Front 38

38. Background Radiation is the source of what percent of human exposure?

Back 38

82%

Front 39

39. The annual effective dose per person from natural background radiation is approxmiately _____.

Back 39

295 mrem

Front 40

40. The greatest source of natural background radiation to humans is _______.

Back 40

Radon

Front 41

41. The smallest parictle of an element that reatins the characteristics of the element is an _____.

Back 41

Atom

Front 42

42. Atomic Mass refers to:

Back 42

The number of neutrons .0


























the number of protons plus the number of neutrons

Front 43

43. Xrays trave as budnles of energy called:

Back 43

Photons

Front 44

44. The height of a sine wave is called:

Back 44

Amplitude

Front 45

45. The number of xray waves passing a given point per unit time is called:

Back 45

Frequency

Front 46

46. The transformer that operates on the principle of self - induction is the:

Back 46

Autotransformer

Front 47

47. Electronic timers used in xray equipment allow for exposure times as low as:

Back 47

1/1000 second

Front 48

48. To ensure consistency of radiographic quality from one exposure to the next, what device may be used?

Back 48

Automatic Exposure Control

Front 49

49. What happens when a predetermined level of ionization is reached in the ionization chamber?

Back 49

The exposure is terminated

Front 50

50. An x-ray machine that uses a continually decreasing mA for the shortest times possible uses a(n):

Back 50

Falling load generator

Front 51

51: An x-ray machine that makes maxiumu use of heat loading potential uses a(n):

Back 51

Falling Load generator

Front 52

52. Devices in the x-ray circuit that operate on the principle of mutual induction are called:

Back 52

Transformers

Front 53

53. The high-voltage section of the x-ray circuit makes use of what type of transformer?

Back 53

Step-up

Front 54

54. The device in the x-ray circuit that changes AC to DC is the _____.

Back 54

Rectifier

Front 55

55. What type of current is required for proper operation of the x-ray tube?

Back 55

Direct

Front 56

56. Modern Rectifiers are made of ________.

Back 56

Silicon-based semiconductors.

Front 57

57. The result of thermionic emission is a(n) _________.

Back 57

Electron Cloud

Front 58

58. The focusing cup is located at the _______.

Back 58

Cathode

Front 59

59. An interaction that produces x-rays at the anode as a result of outer-shell electrons filling holes in the K-shell is called:

Back 59

Characteristic

Front 60

60. When a quality control test is performed to ensure that adjacent mA stations are accurate, the results must be within this amount of one another.

Back 60

10%

Front 61

61. When a quality control test is performed to ensure that the same exposure factors produce consistent x-ray output, successive epxures must be within this amount of one another

Back 61

5%

Front 62

62. When a quality control test is performed to ensure that the collimator is providing appropriate radiation protection, the result must be within this amount.

Back 62

2%

Front 63

63. When a quality control test is performed to ensure that the penetrating ab ility of the xray beam is accurate, the result must be within this amount of the control panel setting:

Back 63

4

Front 64

64. The accuracy of collimation of a 60 inch SID must be

Back 64

+/-1.2 inches