Deck 7: Protection of Patients

Question 1

Half-value layer (HVL) is defined as the thickness of a designated absorber required to

A) decrease the intensity of the primary beam by 50% of its initial value
B) decrease the intensity of the primary beam by 25% of its initial value
C) increase the intensity of the primary beam by 50% of its initial value
D) increase the intensity of the primary beam by 25% of its initial value

Answer 1

A

Question 2

Patient dose decreases when

A) high-speed radiographic film is used in combination with high-speed intensifying screens
B) rare-earth intensifying screens are not used
C) low kVp techniques are used
D) non-screen film is used

Answer 2

A

Question 3

Which of the following is the best type of gonadal shield to use during a sterile field procedure?

A) flat contact
B) shadow
C) shaped contact
D) lead sheet

Answer 3

B

Question 4

Which of the following will best reduce radiation exposure to the patient?

A) use non-screen film
B) use rare-earth screens
C) decrease kVp
D) increase mAs

Question 5

The minimum source-to-tabletop distance permitted in mobile fluoroscopy is

A) 4 inches
B) 9 inches
C) 12 inches
D) 15 inches

Question 6

A fluoroscope must be equipped with a cumulative timing device which times the radiation exposure and sounds an audible alarm after the fluoroscope has been energized for

A) 1 minute
B) 2 minutes
C) 3 minutes
D) 5 minutes

Question 7

The function of a filter is to remove which of the following from the x-ray beam?

A) short wavelength radiation
B) long wavelength radiation
C) secondary radiation
D) scattered radiation

Question 8

Which of the following is not a type of beam limitation device?

A) collimator
B) cone
C) filter
D) aperture diaphragm

Question 9

A computed radiography (CR) system includes the following:
1. storage phosphor cassettes
2. a storage phosphor reader
3. bar code scanner
4. remote operator panel for entering patient date 5. a clinical workstation for reviewing and printing

A) 1, 3 and 5 only
B) 2 and 4 only
C) 1 and 5 only
D) 1, 2, 3, 4 and 5

Question 10

CR photostimulable phosphor cassettes use _____, which causes the screens to fluoresce upon exposure to ionizing radiation from the x-ray tube.

A) thermoluminescent dosimeters
B) optically stimulated luminescent dosimeters
C) europium-activated barium fluorohalide crystals
D) lithium or calcium fluorohalide

Question 11

The minimum source-to-tabletop distance permitted for fixed fluoroscopes is

A) 6
B) 12
C) 15
D) 20

Question 12

To within what percent of the SID must the collimator light and actual irradiated area be accurate?

A) 2%
B) 5%
C) 10%
D) 25%

Question 13

The number of repeat radiographs can be reduced by

A) disregarding communication between patient and radiographer
B) eliminating voluntary patient motion using short exposure times
C) eliminating involuntary patient motion using immobilization devices
D) eliminating voluntary patient motion using immobilization devices

Question 14

Which of the following combinations would reduce patient radiation dose during an x-ray exam?

A) higher kVp, lower mAs, increased filtration
B) lower kVp, higher mAs, decreased filtration
C) higher kVp, higher mAs, decreased filtration
D) lower kVp, lower mAs, increased filtration

Question 15

The greatest beam limitation is accomplished when the cone/cylinder is _____, and the diameter opening is _____.

A) shorter, bigger
B) shorter, smaller
C) longer, bigger
D) longer, smaller

Question 16

How much total filtration is required when using over 70 kVp?

A) 1.5 mm A
B) 2.5 mm Al
C) 3.0 mm Al
D) 4.0 mm Al

Question 17

The tabletop exposure rate during fluoroscopy shall not exceed

A) 1 R/min
B) 5 R/min
C) 7 R/min
D) 10 R/min

Question 18

Which of the following exposure techniques will provide the least amount of radiation exposure to the patient?

A) 50 mAs, 90 kVp
B) 100 mAs, 90 kVp
C) 200 mAs, 50 kVp
D) 400 mAs, 50 kVp

Question 19

The fundamental difference between computed radiography and conventional analog imaging is the replacement of film-screens with

A) thermoluminescent dosimeters
B) optically stimulated luminescent dosimeters
C) photostimulable phosphor plates
D) rare-earth stimulated plates

Question 20

Which of the following is the most versatile type of x-ray beam limitation device?

A) aperture diaphragm
B) cone
C) cylinder
D) collimator

Question 21

Using CR, it is estimated that overexposures of up to _____, and underexposures up to _____ are recoverable, thus eliminating the need for retakes.

A) 50%, 10%
B) 100%, 50%
C) 80%, 500%
D) 500%, 80%

Question 22

When using fluoroscopy, federal law prohibits the useful beam at the image receptor from exceeding the visible image area by more than _____% of the source-to-image receptor distance (SID).

A) 1
B) 3
C) 5
D) 10

Question 23

Which of the following are placed between the patient and the image receptor (IR) to preferentially absorb scatter radiation?

A) lead shielding
B) radiographic grids
C) positioning aides
D) immobilization devices

Question 24

An effective way of reducing patient dose is through

A) accurate and effective positioning
B) using low kVp and high mAs
C) using low kVp and low mAs
D) using high kVp and high mAs

Question 25

In digital radiography (DR), a(n) _____ converts the analog image to a digital image.

A) analog reader
B) digital reader
C) plate converter
D) analog to digital converter (ADC)

Question 26

One way to ensure against irradiating a women in the early stages of pregnancy is to institute _____ for nonemergency procedures.

A) mandatory counseling
B) mandatory scheduling
C) institutional scheduling
D) elective scheduling

Question 27

Which of the following produce the greatest radiation exposure in diagnostic radiology?

A) extremity radiographs
B) spine radiographs
C) skull radiographs
D) fluoroscopic procedures

Question 28

Digital radiography (DR) utilizes a direct capture system of solid state detector plates as the image receptor. These receptors are composed of

A) barium fluorohalide compounds
B) aluminum, tin, and copper
C) lithium fluoride
D) calcium fluoride

Question 29

The dynamic range of exposure for photostimulable phosphors is linear over a range of greater than _____, whereas for analog radiographic imaged produced by screens it is roughly 40 to 1.

A) 10 to 1
B) 100 to 1
C) 1,000 to 1
D) 10,000 to 1

Question 30

Causes of repeat radiographs include the following:
1. dirty screens
2. incorrectly loaded cassettes
3. light leaks
4. chemical fog 5. processor artifacts

A) 1, 2 and 3 only
B) 2, 3 and 4 only
C) 1 and 5 only
D) 1, 2, 3, 4 and 5