Chapter 13 and 15 Flashcards

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1
Q

When the X-ray photon interacts with an inner shell electron and ejects the electron and is totally absorbed in the interaction.

A

Photoelectric absorption

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2
Q

Coherent scatter is also called

A

Classical scatter
Thomson scatter
Unmodified scatter

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3
Q

When X-ray photons interact with orbiting electrons causing them to vibrate

A

Coherent scattering

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4
Q

Which interaction uses very low energy and is not seen in diagnostic X-ray?

A

Coherent scattering or Thomson

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5
Q

When incident photons interacts and removes a loosely bound outer shell electron.

A

Compton scattering

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6
Q

In Compton scattering, the incident photon loses up to ___ of its incoming energy and proceeds in a new direction causing scattering.

A

1/3

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7
Q

Which interaction requires very high energy photons?

A

Pair production

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8
Q

When photons come in and gets close to the nucleus of the atom losing all of its energy in the process.

A

Pair production

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9
Q

Which interaction requires very high energy photons above 10 MeV?

A

Photodisintegration

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10
Q

Which 2 interactions have effects on X-ray images?

A

Photoelectric absorption
Compton scattering

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11
Q

As kVp increases, photoelectric absorption ____

A

Decreases

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12
Q

As KVP increases, Compton scatter ____

A

Increases

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13
Q

Which 2 situation will photoelectric be found?

A

Lower KVP ranges (40-70)
When contrast agents are introduced

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14
Q

Factors contributing to Compton scatter are

A

KVP
Volume of irradiated material

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15
Q

An increased KVP will ______ patient dose

A

Decrease

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16
Q

A decreased KVP will ____ the dose

A

Increase

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17
Q

Volume of irradiated material includes

A

Field size
Patient thickness
Average tissue density

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18
Q

An increased FS will _____ volume of tissue irradiated

A

Increase

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19
Q

Increased FS results in ______ scatter

A

Increased

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20
Q

Decreased FS will _____ beam quantity

A

Decrease

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21
Q

Thicker body parts produce ____ scatter

A

More

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22
Q

______ devices can be used to improve spatial resolution and contrast.

A

Compression

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23
Q

Beam restrictions include

A

Aperture diaphragms
Cones
Cylinders
Collimators
Ancillary devices

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24
Q

The reduction in the number of X-ray photons in the beam, and subsequent loss of energy, as the beam passes through matter.

A

Attenuation

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25
Q

When an X-ray beam passes through matter, it goes through a process called

A

Attenuation

26
Q

The center of the atom is a positively charged nucleus containing

A

Protons and neutrons

27
Q

The energy required to remove an electron from a shell is termed the

A

Binding energy

28
Q

The average atom in the soft tissue of the body has an approximate k-shell binding energy of only

A

0.5 kev

29
Q

What are the 5 interactions between X-ray and matter

A

Photoelectric absorption
Coherent scattering
Compton scattering
Pair production
Photodisintegration

30
Q

kVp affects the ___ of the beam

A

Penetrability

31
Q

Which factors contribute to Compton scatter?

A

KVp and patient thickness

32
Q

Are scatter photons part of the useful beam?

A

No

33
Q

What does a decreased field size do to beam quantity?

A

Decreases it

34
Q

The thicker the body part the _____ scatter

A

More

35
Q

_____ and _____ increase the number of interactions

A

Thickness and density

36
Q

_____ body parts produce more scatter

A

Denser

37
Q

Compression devices are used to improve

A

Spatial resolution And contrast

38
Q

Decreasing part thickness results in _____ patient dose

A

Lower

39
Q

Decreased OID improves

A

Spatial resolution

40
Q

Ideally, beam restrictors decrease ______ to anatomy of interest

A

Field size

41
Q

There are 2 sets of _____ that permit infinite number of field sizes

A

Shutters

42
Q

The bottom shutters reduce

A

Penumbra

43
Q

Geometric unsharpness around periphery of image

A

Penumbra AKA edge unsharpness

44
Q

______ radiation occurs from areas of the X-ray tube other than focal spot area

A

Off focus

45
Q

Off focus radiation produces images beyond

A

Exposed field of radiation

46
Q

The light field needs to be accurate within

A

+/- 2%

47
Q

PBL stands for

A

Positive beam limitation

48
Q

______ degrades image quality by placing exposures on the IR that are unrelated to patient anatomy (fog)

A

Scatter

49
Q

Automatically collimates beam to size of image receptor

A

PBL

50
Q

The upper shutter reduces

A

Off focus radiation reaching IR

51
Q

What is the most common beam restrictor?

A

Collimation

52
Q

Compression bands are routinely used in

A

Mammography

53
Q

For radiographers to get the best possible image we must minimize the amount of ____ reaching the IR

A

Scatter

54
Q

•An image is created when

A

some photons pass through unaffectedwhile others are absorbed

55
Q

The more photons that pass through unaffected, the _____ IR exposure

A

Better

56
Q

The volume of irradiated material is controlled by

A

field size and patient thickness

57
Q

As volume increases, scatter

A

Increases

58
Q

The higher the atomic number is, the ______ photoelectric absorption and ____ scatter

A

More
Less

59
Q

What 3 things absorb radiation and cause a high contrast image when used

A

Barium
Iodine
Lead

60
Q

_____ should never be greater than IR size

A

Field size

61
Q

flat sheet of metal (lead) has opening in the center and attaches to the x-ray tube port

A

Aperture diaphragms

62
Q

Device placed between the patient and IR

A

Grid