Unit 2 CH 10 & 11 Test

Which beam restriction device can be cut to the size needed? A collimator An aperture diaphragm A cylinder A cone

An aperture diaphragm

The number of lead strips per inch in a grid is a measure of: grid selectivity. grid ratio. grid frequency. contrast improvement number.

grid frequency

The height of the lead strips relative to the distance between the lead strips is the measure of: contrast improvement. grid ratio. Bucky factor. grid selectivity.

grid ratio

If the intensity of radiation at 36 inches is 480 mR, what is the intensity if the SID is increased to 72 inches? 360 mR. 240 mR. 120 mR. 60 mR.

120 mR.

The relationship between kVp and the quantity of remnant radiation is known as the kVp-density rule 15% rule 115% rule kVp-quantity rule

15% rule

The smaller the volume of tissue irradiated, the: greater the amount of scatter produced. less the amount of scatter produced. greater the need to use a grid. A and C.

less the amount of scatter produced.

Patient dose increases when: 1. Changing from a higher to a lower grid ratio 2. Changing from a lower to a higher grid ratio 3. A grid is used 1 and 2 only 1 and 3 only 2 and 3 only 1, 2, and 3

2 and 3 only

The amount of mAs required with a grid divided by the amount of mAs needed without a grid is the calculation that determines the: 1. Grid ratio 2. Grid conversion factor 3. Bucky factor 1 and 2 only 1 and 3 only 2 and 3 only 1, 2, and 3

2 and 3 only

If an excellent knee radiograph is produced using 10 mAs and an 8:1 ratio grid, how much mAs will be needed if no grid is available? 2.5 mAs 4 mAs 8 mAs 10 mAs

2.5 mAs

If the intensity of radiation at 36 inches SID is 600 mR, what is the intensity if the distance is increased to 60 inches SID? 216 mR. 359.9 mR. 1000 mR. 1666.7 mR.

216 mR.

SID effects

exposure, spatial resolution, and distortion

central ray angle effects

exposure, spatial resolution, and distortion

Grid ratios range from: 2:1 to 6:1. 5:1 to 16:1 10:1 to 24:1. 20:1 to 32:1.

5:1 to 16:1.

What is the grid conversion factor for a 12:1 ratio grid? 3 × 4 × 5 × 6 ×

5

**When a known mAs at 72 inches SID produces appropriate exposure to the IR, one half of the mAs can be used at 40 inches SID 48 inches SID 56 inches SID 60 inches SID

56 inches SID

Doubling the mAs produces appropriate exposure to the IR when the SID is changed from 40 inches to 36 inches SID 48 inches SID 56 inches SID 60 inches SID

56 inches SID

If 16 mAs produce appropriate IR exposure at 72 inches SID, how much mAs is needed at 48 inches SID to maintain that amount of IR exposure? 7 mAs. 11 mAs. 24 mAs. 36 mAs.

7 mAs.

If 32 mAs produce appropriate IR exposure at 72 inches SID, how much mAs is needed at 36 inches SID to maintain that amount of IR exposure? 8 mAs. 16 mAs. 64 mAs. 128 mAs.

8 mAs.

What mA should be selected to produce 32 mAs using a 0.04 exposure time? 128 mA. 200 mA. 400 mA. 800 mA.

800 mA.

**100 kVp should be changed to __________ kVp to decrease the exposure to the IR by a factor of 2. 50 85 115 none of the above

85

If the height of the grid strip is 16 mm, the distance between the strips is 2 mm, and the strip is 0.3 mm thick, what is the grid ratio? 8:1 10:1 12:1 16:1

8:1

Which of the following are tools that the radiographer can use to limit scatter radiation? Beam-restricting devices Radiographic grids Digital imaging plate A and B

A and B

Changes in SID affect IR exposure and beam intensity contrast and spatial resolution spatial resolution and beam intensity A and C B and C

A and C

**Grids that move during the exposure: are reciprocating grids. move from top to bottom. are part of the Potter-Bucky diaphragm. A and C.

A and C.

Shape distortion is only due to misalignment of the tube or part. True False

False

Changing from an 8:1 grid to a 12:1 grid, along with making the appropriate adjustments, will result in: 1. Increased patient dose 2. An image with increased contrast 3. Using more mAs 1 and 2 only 1 and 3 only 2 and 3 only 1, 2, and 3

1, 2, and 3

How much mAs is produced when the mA is 200 and the exposure time is 0.5 s? 25 mAs. 50 mAs. 100 mAs. 200 mAs.

100 mAs.

An optimal AP abdomen radiograph can be produced using 40 mAs, 75 kVp, and a 12:1 grid. How much mAs would be needed if the only grid available is a 6:1 ratio grid? 20 mAs 24 mAs 67 mAs 80 mAs

24 mAs

**Significant collimation requires an increase of _____________ of the mAs. 0% 1% to 5% 10% to 20% 30% to 50%

30% to 50%

200 mA @ 80 ms (0.08 s) produces 16 mAs. Which of the following exposure factors maintains 16 mAs while using a shorter exposure time? 100 mA @ 0.16 s. 200 mA @ 0.16 s. 400 mA @ 0.04 s. 400 mA @ 0.08 s.

400 mA @ 0.04 s.

**Which of the following beam-restricting devices is least effective at limiting unsharpness surrounding the radiographic image? Collimator Cylinder cone Aperture diaphragm Focused grid

Aperture diaphragm

Which of the following statements is true? A high ratio grid prevents the production of scatter better than a low ratio grid. A low ratio grid is more effective at removing scatter than a high ratio grid. As grid ratio increases, the removal of scatter increases. High ratio grids are less effective at removing scatter than low ratio grids.

As grid ratio increases, the removal of scatter increases.

When the intensities of radiation exiting the patient are very different from each other, the resulting image has low contrast high contrast short-scale contrast A and C B and C

B and C

With digital imaging, overexposure of the IR and excessive dose to the patient can be easily determined by looking at the image brightness HARD to determine by looking at the image brightness determined by checking the exposure indicator value A and C B and C

B and C

Increasing collimation results in reduced patient exposure, increased field size, and reduced scatter production. True False

False

**Which of the following beam-restricting devices is best at limiting unsharpness surrounding the radiographic image? Collimator Cylinder cone Aperture diaphragm Focused grid

Collimator

**Due to increased potential grid cutoff, which would be the most challenging grid to use? Focused linear grid Parallel linear grid Cross-hatched grid Reciprocating grid

Cross-hatched grid

**What type of relationship does mAs have with SID when the goal is to keep the exposure to the IR constant? Direct proportional. Direct but not proportional. Inverse proportional. Inverse but not proportional.

Direct proportional.

What type of relationship do mAs have with the quantity of x-rays produced? Direct proportional. Direct but not proportional. Inverse proportional. Inverse but not proportional.

Direct proportional.

An adult's knee measuring 14 cm should be radiographed without a grid. True False

False

Increased beam restriction means decreased collimation. True False

False

What occurs when the x-ray beam is not properly aligned with the grid strips? Bucky delamination Grid cutoff Increased exposure to the IR Nothing

Grid cutoff

With digital imaging, if the image receptor is not exposed to enough radiation, I. The image brightness will appear appropriate. II. The image brightness will appear high (light). III. Quantum noise will be visible I and II I and III II and III III only

I and III

Which of the following is the correct formula for the inverse square law? I1/I2 = D1/D2. I1/I2 = D2/D1. I1/I2 = (D1)2/(D2)2. I1/I2 = (D2)2/(D1)2.

I1/I2 = (D2)2/(D1)2.

Which of the following statements is true? If the height of the lead strips increases and the space between the grid strips decreases, the grid will be more effective at scatter removal. If the height of the lead strip decreases and the space between the grid strips increases, the grid will be more effective at removing scatter radiation. A high ratio grid removes little scatter. A grid decreases scatter production.

If the height of the lead strips increases and the space between the grid strips decreases, the grid will be more effective at scatter removal.

Which of the following influences the amount of scatter radiation striking the image receptor but not the production of scatter radiation? Reduce the exposure field size. Reduce the tissue thickness. Increase the grid ratio. Ask a patient with a large abdomen to lie prone instead of supine.

Increase the grid ratio

Which of the following is not a way to reduce the production of scatter radiation? Reduce the exposure field size. Reduce the tissue thickness. Increase the grid ratio. Ask a patient with a large abdomen to lie prone instead of supine.

Increase the grid ratio.

What is the result of imaging a thicker part or patient? More Compton interactions Decreased scatter Increased radiographic contrast Decreased fog

More Compton interactions

What type of grid error results in appropriate exposure to the middle of the IR and extreme underexposure along the sides of the IR? Stationary grid Upside-down focused grid Lateral decentering Off-level

Upside-down focused grid

**What is found between the lead strips in a grid? Lead Tungsten Radiopaque material Radiolucent material

Radiolucent material

**Which of the following is not a primary exposure technique factor? KVP. Time of exposure. SID. MA.

SID

**Which grid design is manufactured to match the divergence of the x-ray beam? The parallel grid The crossed grid The reciprocating grid The focused grid

The focused grid

Why does the air-gap technique work? The scatter photons increase in energy as a result of the distance to the image receptor. The scatter photons are more likely to miss the image receptor. Less scatter is produced. A and C

The scatter photons are more likely to miss the image receptor.

What purpose does positive beam limitation serve? To prevent the technologist from placing an image receptor in the Bucky tray that is too large for the study performed To allow the technologist to use an exposure field larger than the image receptor size To prevent first-year students from having to repeat studies by not aligning the Bucky tray with the image receptor To reduce patient exposure by limiting the exposure field to the same size as the image receptor in the Bucky tray

To reduce patient exposure by limiting the exposure field to the same size as the image receptor in the Bucky tray

As collimation decreases, exposure to the IR increases. True False

True

Grids do not reduce scatter production. True False

True

More scatter radiation exits the patient when using higher kilovoltage. True False

True

In general, when should a grid be used? When part thickness exceeds 4 cm When kV exceeds 40 kVp When kV exceeds 1.02 MeV When part thickness exceeds 10 cm

When part thickness exceeds 10 cm

Decreasing collimation results in: a smaller field size. a larger field size. decreased patient dose. less scatter production.

a larger field size

When a grid is needed but not available, the _____ may be used for certain examinations. tomographic technique air-gap technique Seldinger technique reverse collimation technique

air-gap technique

Increasing the kVp increases the energy of the x-ray photons increases the quantity of x-ray photons increases the penetrating power of x-ray photons all of the above

all of the above

**Focal spot size is determined by the amount of kVp cathode filament size cathode focusing cup size all of the above

cathode filament size

A beam-restricting device that has two or three sets of lead shutters is a(n): collimator. aperture diaphragm. cone. cylinder.

collimator

An aperture diaphragm with an attached elongated tube is a(n): collimator. aperture diaphragm. Grid. cylinder.

cylinder

**Decreasing grid ratio (with no change in frequency) results in _____________scatter cleanup and ____________ lead content. decreased; decreased decreased; increased increased; decreased increased; increased

decreased; decreased

As beam restriction increases, field size and patient dose _________________. increases decreases does not change

decreases

As beam restriction increases, the quantity of scatter radiation __________ and radiographic contrast ___________. increases; increases decreases; increases decreases; decreases increases; decreases

decreases; increases

Increasing the kVp by 15% has the same effect as increasing the mAs by 15% doubling the mAs decreasing the mAs by 15% halving the mAs

doubling the mAs

mAs effects

exposure

Beam restriction (field size) effects

exposure and contrast

Grid ratio effects

exposure and contrast

kVp effects

exposure and contrast

OID effects

exposure, contrast, spatial resolution, and distortion

Patient thickness effects

exposure, contrast, spatial resolution, and distortion

The recommended SIDs that can be used with a focused grid describe the: focal distance. convergent point. focal range. convergent line.

focal range.

The larger the x-ray beam field size, the _________ the amount of scatter radiation produced. greater lesser

greater

A device consisting of very thin lead strips with radiolucent interspaces intended to absorb scatter radiation emitted from the patient is a: collimator. aperture diaphragm. cone. grid.

grid

Grid ratio can be expressed mathematically as: thickness of lead strips divided by distance between them. height of lead strips divided by distance between them. height of lead strips divided by thickness of lead strips. length of lead strips divided by distance between them.

height of lead strips divided by distance between them.

**When the SID is increased from 36 inches SID to 72 inches SID, the mAs must be _____________ to maintain exposure to the IR. decreased increased kept the same

increased

Which of the following is the correct formula for the mAs/distance compensation formula? mAs1/mAs2 = SID1/SID2. mAs1/mAs2 = SID2/SID1. mAs1/mAs2 = (SID1)2/(SID2)2. mAs1/mAs2 = (SID2)2/(SID1)2.

mAs1/mAs2 = (SID1)2/(SID2)2.

With digital imaging, the relationship between mAs and image brightness is direct direct proportional inverse none of the above

none of the above

Also called lateral decentering, the _____ grid error results when the central ray is not aligned to the middle of a focused grid. off-level off-focus off-center upside-down focused

off-center

**The most common cause of grid cutoff is due to: using a focused grid upside down. off-center misalignment. off-focus misalignment. off-level misalignment

off-level misalignment

A grid whose lead strips run perpendicular to the long axis of the grid is called a(n): long dimension grid. short dimension grid. cross-hatch grid. alternating grid.

short dimension grid.

Focal spot size effects

spatial resolution

Patient motion effects

spatial resolution

With digital imaging, if the image receptor is not exposed to enough radiation the image brightness will appear low (dark) the image brightness will appear appropriate the image brightness will appear high (light) none of the above

the image brightness will appear appropriate

With digital imaging, if the mAs is too high the image brightness will appear low (dark) the image brightness will appear appropriate the image brightness will appear high (light) none of the above

the image brightness will appear appropriate

What is the quality control requirement in regard to perpendicularity of the central ray?

within 1 degree

What is the quality control requirement in regard to collimator misalignment?

within 2% of the SID