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Exposure And Imaging > Ch.6 (not Complete) > Flashcards

Ch.6 (not Complete) Flashcards

1
Q

Directly proportional to radiation quantity exiting the x-ray tube
Inversely related to exposure time to maintain exposure to image receptor (IR)

A

Milliamperage (mA)

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2
Q

Directly proportional to radiation quantity exiting the x-ray tube
Inversely related to mA to maintain exposure to IR

A

Exposure time (TIME)

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3
Q

Directly related to radiation quality and quantity exiting the x-ray tube
Inversely related to radiographic contrast

A

Kilovoltage (kVp)

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4
Q

Milliamperage and exposure time have a _______ proportional relationship when discussing quality

A

Direct

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5
Q

Increasing mA = _____ time = _______ quality

A

Increase, increase

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6
Q

**mAs is INVERSELY related to exposure but DIRECTLY related to quantity

A

!!!

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7
Q

Increasing or decreasing the mA results in a _____ change in mAs.

A

Proportional

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8
Q

T or F - MAs does not control brightness

A

TRUE

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9
Q

In order to maintain exposure, by increasing your mA you will need to ______ time

A

Decrease

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10
Q

MA and exposure time have an _____ proportional relationship when maintaining mAs.

A

Inverse

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11
Q

Increasing kVp= ______ penetration = ______ absorption = _______ contrast

A

Increases, decreases, decreases

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12
Q

Increasing kVp _____ subject contrast

A

Decreases

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13
Q

Decreasing kVp ______ subject contrast

A

Increases

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14
Q

What is the 15% rule?

A

By increasing your kVp by 15%, it is the equivalent of doubling your MAs.

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15
Q

Increase for 15% rule

A

1.15

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16
Q

Decrease by 15% rule

A

0.85

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17
Q

How to maintain exposure to the IR

A
  1. Increase mA and proportionally decrease time
  2. Increase time and proportionality decrease
  3. Increase kVp 15% and decrease MAs by half
  4. Decrease kVp 15% and increase MAs by two times
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18
Q

Image brightness is _______ on MAs and kVp

A

Not dependent

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19
Q

Image contrast is _________ on kVp

A

Not dependent

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20
Q

Image brightness and image contrast are both

A

Dependent on the computer

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21
Q

With too little MAs and/or kVp, computer processing will adjust image brightness and contrast BUT

A

Quantum noise is visible, therefore the image will need to be repeated.

22
Q

For digital, using _____kVp and _____ MAs values.

A

Higher, lower

23
Q

With too much kVp/mAs, computer processing with adjust the image brightness and contrast BUT

A

The patient is overexposed.

24
Q

Increasing MAs= ______ noise

A

Decrease

25
Q

Secondary factors include

A
  • focal spot size
  • SID
  • OID
  • Part/IR alignment
  • Grids
  • Beam restriction
  • generator output
  • tube filtration
  • compensating filters
  • patient factors
26
Q

The size of the focal spot affects ______ and _______ _______ recorded in the image.

A

Unsharpness and spatial resolution

27
Q

Increasing focal spot size, unsharpness ______ and spatial resolution _______

A

Increases, decreases

28
Q

Decreasing focal spot size _______ unsharpness and _______ spatial resolution.

A

Decreases, increases

29
Q

SID and radiation intensity are ______ related.

A

Inversely

30
Q

Changing the SID requires a change in ____ to maintain consistent radiation exposure to the image receptor

A

MAs

31
Q

SID affects _________ and __________

A

Distortion and recorded detail/spatial resolution

32
Q

Increasing SID= ______ magnification and _____ spatial resolution

A

Decrease, increase

33
Q

Decreasing SID= ______ magnification= ________ spatial resolution

A

Increases, decreases

34
Q

What is the formula for the direct square law?

A

MAs2=mAs1x(D2/D1)^2

35
Q

What is the formula for exposure maintenance?

A

MAs1/mAs2= (SID1/SID2)^2

36
Q

OID affects

A

Radiation intensity reaching the IR
Amount of scatter radiation reaching the IR
Magnification
Spatial Resolution
(Increase mag.=decrease SR)

37
Q

Increasing OID will have what effect on beam intensity ?

A

It will decrease beam intensity, hence decreasing exposure.
Once exposure to the IR is decreases, you will need to INCREASE MAS

38
Q

An ________ will decrease the intensity of radiation and scatter reaching the IR without the use of a grid.

A

Air Gap

39
Q

Increasing OID=______ IR exposure=______contrast and magnification= _______ SR

A

Decreases, increases, decreases

40
Q

Decreasing OID= ________ IR exposure= _______ contrast and magnification= _______ SR

A

Increases, decreases, increases

41
Q

What is the formula to find the magnification factor?

A

MF= SID/SOD
MF= Image size/Object size

42
Q

What is the formula to solve for SOD?

A

SOD=SID-OID

43
Q

What is the best magnification factor?

A

1

44
Q

Shape distortion can occur from any misalignment of the CR alongside these three factors:

A
  1. X-ray tube
  2. Part being radiographed
  3. IR
45
Q

Improper CR alignment causes shape distortion, as well as

(ON TEST)

A
  1. Incorrect SID
  2. Off centered CR
  3. Angled CR
46
Q

What effect do grids have on spatial resolution ?

A

Increases spatial resolution

47
Q

Less scatter=______ contrast

A

Increase

48
Q

When using the magnification factor formula, what formula would be used in order to find the object size?

A

Obj. Size= image size/MF

49
Q

What is the formula for Grid Conversion?

A

Mas1/mAs2=grid ratio 1/grid ratio 2

50
Q

What is the formula for grid ratio ?

A

Grid ratio=height of lead strips/distance btw strips

51
Q

The more effective the grid, the _______ the mAs

A

GREATER

Exposure And Imaging (6 decks)

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