Physics test 2 Flashcards

1
Q

T/F Overexposing to eliminate noise is a violation of ALARA.

A

True

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2
Q

The exposure number comes from which of the following:

a. coherent radiation
    b. remnant beam
b. light beam
c. scatter
A

b. remnant beam

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3
Q

When you think of scatter, which of the following do you think of?

a. coherent
b. photoelectric
c. compton
d. remnant beam
A

c. compton

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4
Q

What is the phosphor layer in the reader made from?

A

barium fluorhalide

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5
Q

What is the order of the layers of the reader, top to bottom:

a. support layer, conductive layer, reflective layer, phosphor layer, protected layer
b. protected layer, phosphor layer, conductive layer, reflective layer, support layer
c. protected layer, phosphor layer, reflective layer, conductive layer, support layer
d. phosphor layer, protected layer, reflective layer, conductive layer, support layer
A

c. protected layer, phosphor layer, reflective layer, conductive layer, support layer

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6
Q

Which layer sends light in a forward direction?

A

reflective layer

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7
Q

What does the material in the phosphor layer do?

A

traps the electrons

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8
Q

What does a photo multiplier do?

A

converts light to an electronic signal

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9
Q

How does a reader create an image after the cassette is inserted?

A

PSP is exposed, laser scans, light is given off, photo multiplier, digitizer

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10
Q

What does a digitizer do?

A

it converts an electronic signal to a number (an analog to digital converter)

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11
Q

T/F The numbers in the matrix are associated with black and white.

A

False (various shades of grey)

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12
Q

Brightness is what we refer to on an analog image as:

A

Density

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13
Q

What is the term for a formula in a computer?

A

Algorithm

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14
Q

What is the term for the graph of the exposure?

A

Histogram

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15
Q

Which comes from the patient?

a. photoelectric xrays
b. coherent scatter
c. compton scatter
d. bremsstrahlung
A

Compton Scatter

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16
Q

When a proton hits an inner shell electron, ejecting it, this is called:

A

Photoelectric Effect

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17
Q

Compton scatter does which of the following:

a. increases resolution, making the image darker
b. creates a layer of density, making the image clearer
c. creates a layer of density, making the image darker
d. increases resolution, making the image clearer
A

creates a layer of density, making the image darker

18
Q

How does the laser scan the PSP in the reader?

A

In a raster motion

19
Q

Why are photoelectric rays referred to as money?

A

Because of the complete attenuation

20
Q

Which of the following is true of bremsstrahlung:

a. Move from L to K shell
b. are slow-moving
c. move from the M to k shell
d. all of the above
A

Move from L to K shell (not enough energy in other transitions, is fast-moving, electron comes close to the nucleus, changes direction)

21
Q

What is the term used for absorption of energy?

A

Attenuation

22
Q

T/F When an electron is ejected from an inner shell resulting in a cascade effect, low energy photons are produced.

A

True (photoelectric effect)

23
Q

Which is true of the grid:

a. it absorbs scatter
b. it is a series of  strips made from rare earth metals
c. primary beams are absorbed
d. all of the above
A

it absorbs scatter (strips made of lead, primary beams go through)

24
Q

T/F Compton scatter is found in things with a high atomic number, such as bone, lead, and barium.

A

False (photoelectric)

25
Q

Image receptors have intensifying screens made of rare earth phosphors (Gadolunium, Lanthanum, yettrium), why?

a. rare earth metals require less radiation
b. to absorb radiation and give off light
c. it creates a density that results in an image on the film
d. all of the above
A

All of the above

26
Q

. T/F Rare earth phosphor is difficult to work with.

A

True

27
Q

T/F Thicker body parts require a grid, because they produce more scatter.

A

True

28
Q

The slats in the grid do what?

A

Absorb the scatter

29
Q

What are the steps for processing film in a dark room?

A

developer, fixer, water, dryer

30
Q

Which of the following is an alkaline solution containing six chemicals including sulfide?

a. fixer
b. drying solution
c. developer
d. brightener
A

Developer

31
Q

. Each square on a matrix is ____ pixel (s).

A

1

32
Q

Which would have a better resolution:

a. large format with very tiny pixels
b. small format with very tiny pixels
c. large format with large pixels
d. small format with large pixels
A

large format with very tiny pixels

33
Q

Which of the following is a drawback to images with increased resolution:

a. longer processing time
b. longer transmission time
c. takes up more storage space
d. all of the above
A

All of the above

34
Q

The numbers on the matrix correspond to what?

A

A shade of gray

35
Q
Advantages of digital over analog include:
	I. better access to images
	II. ability to tweak
	III. difficult to lose image
	IV. increased throughput
A

I, II, III, and IV

36
Q

. Which of the following is false with regards to C.R.?

a. Spacial resolution is better.
b. Brightness replaces density
c. The digitizer converts light to a number
d. Soft tissues are better demonstrated
A

The digitizer converts light to a number (digitizer converts an electronic signal to a number, while the photo multiplier converts light to an electronic signal)

37
Q

T/F In C.R., cassettes can be reused multiple times before they need to be erased.

A

False (they must be erased between each use to avoid double exposure)

38
Q

T/F Tweaking is done post processing.

A

True

39
Q

The benefits of tweaking include:

a. saves repeat exposure
d. decreases throughput
c. can fix blurriness caused by a patient moving
d. can be done before processing
A

Saves repeat exposure

40
Q

What is the term for the beam that exits the patient?

A

Remnant beam

41
Q

Where do target interactions take place?

A

Anode

42
Q

Incidence electrons come from:

A

The cathode