Pt 12

A fluoroscopic examination requires 3 minutes of exposure on time. If the exposure rate for the examination is 3 mGy/hr, what is the approximate exposure for the three minute procedure? A. 3 mGy B. 1.5 mGy C. 0.75 mGy D. 0.15 mGy

0.15 mGy

An increase in the kilovoltage applied to the x-ray tube increases the: 1. percentage of high-energy photons produced. 2. beam intensity. 3. patient absorption.

1 & 2

Greater latitude is available to the radiographer in which of the following circumstances? 1. Using high-kV technical factors 2. Using a low-ratio grid 3. Using low-kV technical factors

1 & 2

According to the line-focus principle, an anode with a small angle provides: 1. improved spatial resolution. 2. improved heat capacity. 3. less heel effect.

1 & 2 only

The factors that impact spatial resolution include: 1. Focal spot size 2. Type of rectification 3. SID

1 & 3

Which of the following function(s) to reduce the amount of scattered radiation reaching the IR? 1. Grid devices 2. Restricted focal spot size 3. Beam restrictors

1 & 3

The functions of automatic beam limitation devices include: 1. reducing the production of scattered radiation 2. increasing the absorption of scattered radiation 3. changing the quality of the x-ray beam

1 only

A lateral radiograph of the cervical spine was made at 40 in. using 300 mA and 0.03 second exposure. If it is desired to increase the distance to 72 in., what should be the new milliampere (mA) setting, all other factors remaining constant? A. 400 mA B. 800 mA C. 1000 mA D. 1200 mA

1000 mA

Characteristics of high-ratio focused grids, compared with lower-ratio grids, include which of the following? 1. They allow more positioning latitude. 2. They are more efficient in collecting SR. 3. They absorb more of the useful beam.

2 & 3

An increase in the kilovoltage applied to the x-ray tube increases the: 1. x-ray wavelength 2. exposure rate 3. patient absorption

2 only

If 85 kVp, 400 mA, and ⅛ s were used for a particular exposure using single-phase equipment, which of the following milliamperage or time values would be required, all other factors being constant, to produce a similar receptor exposure using three-phase, 12-pulse equipment? A. 200 mA B. 600 mA C. 0.125 s D. 0.25 s

200 mA

The exposure factors of 400 mA, 70 ms, and 78 kV were used to produce a particular receptor exposure. A similar radiograph can be produced using 500 mA, 90 kV, and: a. 14 ms b. 28 ms c. 56 ms d. 70 ms

28 ms

Both radiographic images shown in the figure below were made of the same subject using identical exposure factors. Which of the following statements correctly describe(s) these images? 1. Image A demonstrates less receptor exposure because a shorter SID was used. 2. Image A demonstrates more receptor exposure because the subject was turned PA. 3. Image B demonstrates more receptor exposure because a shorter SID was used.

3 only

Which of the following groups of exposure factors would be most appropriate for a sthenic adult IVU? A. 300 mA, 0.02 s, 72 kVp B. 300 mA, 0.01 s, 82 kVp C. 150 mA, 0.01 s, 94 kVp D. 100 mA, 0.03 s, 82 kVp

A. 300 mA, 0.02 s, 72 kVp (high mAs, low kVp)

Of the following groups of analog exposure factors, which is likely to produce the shortest scale of image contrast? A. 500 mA, 0.040 second, 70 kV B. 100 mA, 0.100 second, 80 kV C. 200 mA, 0.025 second, 92 kV D. 700 mA, 0.014 second, 80 kV

A. 500 mA, 0.040 second, 70 kV

A part whose width is 6 inches will be imaged at 44 inches SID. The part to be imaged lies 9 inches from the IR. What will be the projected image width of the part? A. 8 inches B. 10 inches C. 12 inches D. 20 inches

A. 8 inches

The symbols and are examples of which of the following? A. Isotopes B. Isobars C. Isotones D. Isomers

A. Isotopes

If a radiograph exposed using a 12:1 ratio grid exhibits a loss of receptor exposure at its lateral edges, it is probably because the A. SID was too great B. grid failed to move during the exposure C. x-ray tube was angled in the direction of the lead strips D. central ray was off-center

A. SID was too great

A radiograph exposed using a 12:1 ratio focused grid may exhibit a loss of receptor exposure at its lateral edges because the A. SID was too great. B. grid failed to move during the exposure. C. x-ray tube was angled in the direction of the lead strips. D. CR was off-center.

A. SID was too great.

To produce a just perceptible increase in receptor exposure, the radiographer should increase the A. mAs by 30% B. mAs by 15% C. kV by 15% D. kV by 30%

A. mAs by 30%

All the following are related to spatial resolution except A. milliamperage B. focal-spot size C. source-to-object distance D. OID

A. milliamperage

Linear energy transfer (LET) may be best described as A. the amount of energy delivered per distance traveled in tissue. B. the unit of absorbed dose. C. radiation equivalent man. D. radiation absorbed dose.

A. the amount of energy delivered per distance traveled in tissue.

Foreshortening can be caused by A. the radiographic object being placed at an angle to the IR B. excessive distance between the object and the IR C. insufficient distance between the focus and the IR D. excessive distance between the focus and the IR

A. the radiographic object being placed at an angle to the IR

As grid ratio is decreased, A. the scale of contrast becomes longer B. the scale of contrast becomes shorter C. receptor exposure decreases D. radiographic distortion decreases

A. the scale of contrast becomes longer -Because lead content decreases when grid ratio decreases, a smaller amount of scattered radiation is trapped before reaching the IR. More grays, therefore, are recorded, and a longer scale of contrast results. Receptor exposure would increase with a decrease in grid ratio. Grid ratio is unrelated to distortion.

When the radiographer selects kilovoltage on the control panel, which device is adjusted? A. Step-up transformer B. Autotransformer C. Filament circuit D. Rectifier circuit

Autotransformer

In an AP abdomen radiograph taken at 105-cm SID during an IVU series, one renal shadow measures 9 cm in width. If the OID is 18 cm, what is the actual width of the kidney? A. 5 cm B. 7.5 cm C. 11 cm D. 18 cm

B 7.5 cm

An exposure was made at 40-in. SID using 5 mAs and 105 kVp with an 8:1 grid. In an effort to improve image contrast, the image is repeated using a 12:1 grid and 90 kVp. Which of the following exposure times will be most appropriate, using 400 mA, to maintain the original receptor exposure? A. 0.01 s B. 0.03 s C. 0.1 s D. 0.3 s

B. 0.03 s

Of the following groups of technical factors, which will produce the greatest receptor exposure? A. 10 mAs, 74 kV, 44-in. SID B. 10 mAs, 74 kV, 36-in. SID C. 5 mAs, 85 kV, 48-in. SID D. 5 mAs, 85 kV, 40-in. SID

B. 10 mAs, 74 kV, 36-in. SID

A 5-in. object to be radiographed at a 44-in. SID lies 6 in. from the IR. What will be the image width? A. 5.1 in. B. 5.7 in. C. 6.1 in. D. 6.7 in.

B. 5.7 in

The best way to control voluntary motion is A. immobilization of the part. B. careful explanation of the procedure. C. short exposure time. D. physical restraint.

B. careful explanation of the procedure.

Combinations of milliamperage and exposure time that produce a particular milliampere-seconds value will produce identical receptor exposure. This statement is an expression of the A. inverse-square law B. line-focus principle C. reciprocity law D. D log E curve

C reciprocity law

Which of the following terms is used to describe unsharp edges of tiny radiographic details? A. Diffusion B. Mottle C. Blur D. Umbra

C. Blur

If a particular grid has lead strips 0.40 mm thick, 4.0 mm high, and 0.25 mm apart, what is its grid ratio? A. 8:1 B. 10:1 C. 12:1 D. 16:1

D. 16:1 -Grid ratio is defined as the ratio between the height of the lead strips and the width of the distance between them (i.e., their height divided by the distance between them). If the height of the lead strips is 4.0 mm and the lead strips are 0.25 mm apart, the grid ratio must be 16:1 (4.0 divided by 0.25). The thickness of the lead strip is unrelated to grid ratio.

Which of the following radiologic projections would deliver the greatest ESE? A. PA Chest B. Lateral Skull C. AP Pelvis D. AP Lumbar spine

D. AP lumbar spine

Typical examples of digital imaging include MRI CT CR A. 1 only B. 1 and 2 only C. 1 and 3 only D. 1, 2, and 3

D. All 3

How is SID related to exposure rate and receptor exposure? A. As SID increases, exposure rate increases and radiographic receptor exposure increases. B. As SID increases, exposure rate increases and radiographic receptor exposure decreases. C. As SID increases, exposure rate decreases and radiographic receptor exposure increases. D. As SID increases, exposure rate decreases and radiographic receptor exposure decreases.

D. As SID increases, exposure rate decreases and radiographic receptor exposure decreases

A patient is being positioned for a particular radiographic examination. The x-ray tube, image recorder, and grid are properly aligned, but the body part is angled. Which of the following will result? A. Grid cutoff at the periphery of the image B. Grid cutoff along the center of the image C. Increased receptor exposure at the periphery D. Image distortion

D. Image distortion

When the collimated field must extend past the edge of the body, allowing primary radiation to strike the tabletop, as in a lateral lumbar spine radiograph, what may be done to prevent excessive receptor exposure owing to undercutting? A. Reduce the milliampere-seconds. B. Reduce the kilovoltage. C. Use a shorter SID. D. Use lead rubber to absorb tabletop primary radiation.

D. Use lead rubber to absorb tabletop primary radiation.

Which of the following has the greatest effect on receptor exposure? A. Aluminum filtration B. Kilovoltage C. SID D. Scattered radiation

SID

Distortion can be caused by: 1. tube angle 2. the position of the organ or structure within the body 3. the radiographic positioning of the part

all 3

Which of the following can affect radiographic contrast? 1. LUT 2. Pathology 3. OID

all 3

Which of the following factors impact(s) spatial resolution? 1. Focal spot size 2. Subject motion 3. SOD

all 3

Which of the following factors impact(s) spatial resolution? 1. Focal spot size 2. Subject motion 3.. SOD

all 3

The principle stochastic effect of radiation, of those listed below, is A. blood changes B. genetic alterations C. cataractogenesis D. reduced fertility

genetic alterations

The relationship between the height of a grid's lead strips and the distance between them is referred to as grid A. ratio B. radius C. frequency D. focusing distance

ratio

If a radiograph were made of an average-size knee using automatic exposure control (AEC) and all three photocells were selected, the resulting radiograph would demonstrate A. underexposed image. B. overexposed image. C. poor spatial resolution. D. adequate exposure.

underexposed image