Physics test 2

Question 1

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

Answer 1

True

Question 2

The exposure number comes from which of the following:

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

Answer 2

b. remnant beam

Question 3

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

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

Answer 3

c. compton

Question 4

What is the phosphor layer in the reader made from?

Answer 4

barium fluorhalide

Question 5

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

Answer 5

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

Question 6

Which layer sends light in a forward direction?

Answer 6

reflective layer

Question 7

What does the material in the phosphor layer do?

Answer 7

traps the electrons

Question 8

What does a photo multiplier do?

Answer 8

converts light to an electronic signal

Question 9

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

Answer 9

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

Question 10

What does a digitizer do?

Answer 10

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

Question 11

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

Answer 11

False (various shades of grey)

Question 12

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

Answer 12

Density

Question 13

What is the term for a formula in a computer?

Answer 13

Algorithm

Question 14

What is the term for the graph of the exposure?

Answer 14

Histogram

Question 15

Which comes from the patient?

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

Answer 15

Compton Scatter

Question 16

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

Answer 16

Photoelectric Effect

Question 17

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

Answer 17

creates a layer of density, making the image darker

Question 18

How does the laser scan the PSP in the reader?

Answer 18

In a raster motion

Question 19

Why are photoelectric rays referred to as money?

Answer 19

Because of the complete attenuation

Question 20

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

Answer 20

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

Question 21

What is the term used for absorption of energy?

Answer 21

Attenuation

Question 22

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

Answer 22

True (photoelectric effect)

Question 23

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

Answer 23

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

Question 24

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

Answer 24

False (photoelectric)

Question 25

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

Answer 25

All of the above

Question 26

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

Answer 26

True

Question 27

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

Answer 27

True

Question 28

The slats in the grid do what?

Answer 28

Absorb the scatter

Question 29

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

Answer 29

developer, fixer, water, dryer

Question 30

Which of the following is an alkaline solution containing six chemicals including sulfide? a. fixer b. drying solution c. developer d. brightener

Answer 30

Developer

Question 31

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

Answer 31

1

Question 32

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

Answer 32

large format with very tiny pixels

Question 33

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

Answer 33

All of the above

Question 34

The numbers on the matrix correspond to what?

Answer 34

A shade of gray

Question 35

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

Answer 35

I, II, III, and IV

Question 36

. 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

Answer 36

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)

Question 37

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

Answer 37

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

Question 38

T/F Tweaking is done post processing.

Answer 38

True

Question 39

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

Answer 39

Saves repeat exposure

Question 40

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

Answer 40

Remnant beam

Question 41

Where do target interactions take place?

Answer 41

Anode

Question 42

Incidence electrons come from:

Answer 42

The cathode