5 Radreview minimum patient exposure Flashcards

Patient dose increases as fluoroscopic

A
FOV increases
B
FOV decreases
C
FSS increases
D
FSS decreases

Referring to the nomogram in Figure 3–3, what is the approximate patient ESE from an AP projection of the abdomen made at 105 cm using 70 kVp, 300 mA, 200 ms, and 2.5 mm Al total filtration?

A
5 mR
B
166 mR
C
245 mR
D
288 mR

Which of the following statements is (are) true with respect to radiation safety in fluoroscopy?

Tabletop radiation intensity must not exceed 2.1 R/min/mA.
Tabletop radiation intensity must not exceed 10 R/min.
In high-level fluoroscopy, tabletop intensity up to 20 R/min is permitted.

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

Which of the following most effectively minimizes radiation exposure to the patient?

A
Small focal spot
B
Low-ratio grids
C
Increased SID
D
High-speed intensifying screens

When an image intensifier's magnification mode is used,
1. output screen gain is increased.
2. resolution increases.
3. patient dose increases.

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

Which of the dose–response curves shown in Figure 3–7 is representative of radiation-induced skin erythema?

Dose–response curve A
Dose–response curve B
Dose–response curve C

A
1 only

B
1 and 2 only

C
3 only

D
2 and 3 only

If the exposure rate to an individual standing 2.0 m from a source of radiation is 15 R/min, what will be the dose received after 2 minutes at a distance of 5 m from the source?

A
1.2 R
B
2.4 R
C
4.8 R
D
9.6 R

Which one of the following is (are) used to control the production of scattered radiation?

Collimators
Optimal kV
Use of grids

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

Moving the image intensifier closer to the patient during traditional fluoroscopy

decreases the SID
decreases patient dose
improves image quality

A
1 only
B
1 and 2 only
C
1 and 3 only
D
1, 2, and 3

At least how many HVLs are required to reduce the intensity of a beam of monoenergetic photons to less than 10% of its original value?

A 2

B 3

C 4

D 5

Which of the following is (are) characteristic(s) of a 16:1 grid?

It absorbs more useful radiation than an 8:1 grid.
It has more centering latitude than an 8:1 grid.
It is used with higher-kilovoltage exposures than an 8:1 grid.

A
1 only
B
1 and 3 only
C
2 and 3 only
D
1, 2, and 3

How does the use of rare earth intensifying screens contribute to lowering the patient dose?

It permits the use of lower milliampere-seconds
It permits the use of lower kilovolts peak (kVp)
It eliminates the need for patient shielding

A
1 only
B
1 and 2 only
C
1 and 3 only
D
2 and 3 only

What is the approximate ESE for the average upright PA chest radiograph using 115 kVp and a grid?

A
20 rad
B
20 mrad
C
200 rad
D
200 mrad

Which of the following will reduce patient dose during fluoroscopy?
1. Decreasing the source-skin distance (SSD)
2. Using 2.5 mm Al filtration
3. Restricting tabletop intensity to less than 10 R/min

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

Which of the following is most likely to permit the greatest decrease in patient exposure?

A
Changing from a 200-speed system to a 400-speed system
B
Increasing kilovoltage by 15% and cutting the milliampere-seconds value in half
C
Changing collimation from 10 × 12 to 14 × 17
D
Changing from an 8:1 grid technique to nongrid

Which of the following projections is most likely to deliver the largest dose to the ovaries?

A
AP lumbar spine, 7 × 17 in. cassette, 80 kVp
B
AP lumbar spine, 14 × 17 in. cassette, 80 kVp
C
AP abdomen, 80 kVp
D
AP abdomen, 70 kVp

Which of the following tissues is (are) considered to be particularly radiosensitive?

Intestinal mucous membrane
Epidermis of extremities
Optic nerves

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

Which one of the following is (are) used to control the production of scattered radiation?

Collimators
Optimal kV
Use of grids

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

An increase in total filtration of the x-ray beam will increase

A
patient skin dose
B
beam HVL
C
image contrast
D
milliroentgen (mR) output

What is the approximate ESE for the average AP lumbar spine radiograph?

A
30 rad
B
30 mrad
C
300 rad
D
350 mrad

If a patient received 2000 mrad during a 10-minute fluoroscopic examination, what was the dose rate?

A
0.2 rad/min
B
2.0 rad/min
C
5 rad/min
D
200 rad/min

The source-to-table distance in fixed/stationary fluoroscopy must

A
be at least 15 in.
B
not exceed 15 in.
C
be at least 12 in.
D
not exceed 12 in.

If a patient received 1,400 mrad during a 7-minute fluoroscopic examination, what was the dose rate?

A
200 rad/min
B
5 rad/min
C
2.0 rad/min
D
0.2 rad/min

Which of the following factors will affect both the quality and the quantity of the primary beam?

Half-value layer (HVL)
Kilovolts (kV)
Milliamperes (mA)

A
1 only
B
1 and 2 only
C
1 and 3 only
D
1, 2, and 3

The advantages of beam restriction include which of the following?

Less scattered radiation is produced.
Less biologic material is irradiated.
Less total filtration will be necessary.

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

The interaction illustrated in Figure 3–5

can pose a safety hazard to personnel
can have a negative impact on image quality
occurs with low-energy incident photons

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

What quantity of radiation exposure to the reproductive organs is required to cause temporary infertility?

A
100 rad
B
200 rad
C
300 rad
D
400 rad

If a patient received 0.9 rad during a 3-minute fluoroscopic examination, what was the dose rate?

A
3 mrad/min
B
30 mrad/min
C
300 mrad/min
D
3,000 mrad/min

What is the approximate entrance skin exposure (ESE) for the average AP supine lumbar spine radiograph?

A
350 rad
B
350 mrad
C
35 rad
D
35 mrad

Which of the following radiation situations is potentially the most harmful?

A
A large dose to a specific area all at once
B
A small dose to the whole body over a period of time
C
A large dose to the whole body all at one time
D
A small dose to a specific area over a period of time

How does filtration affect the primary beam?

A
It increases the average energy of the primary beam.
B
It decreases the average energy of the primary beam.
C
It makes the primary beam more penetrating.
D
It increases the intensity of the primary beam.

Which of the following result(s) from restriction of the x-ray beam?

Less scattered radiation production
Less patient hazard
Less radiographic contrast

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

Which of the following has (have) an effect on the amount and type of radiation-induced tissue damage?

Quality of radiation
Type of tissue being irradiated
Fractionation

A
1 only
B
1 and 2 only
C
1 and 3 only
D
1, 2, and 3

Filtration is added to the x-ray beam to

A
decrease photoelectric interaction.
B
remove the "hard" x-rays.
C
produce a more heterogeneous x-ray beam.
D
produce an x-ray beam with higher average energy.

Which of the following will increase patient dose during fluoroscopy?

Decreasing the SSD
Using 2.5 mm Al filtration
Restricting tabletop intensity to less than 10 R/min

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

How many HVLs are required to reduce the intensity of a beam of monoenergetic photons to less than 15% of its original value?

A 2

B 3

C 4

D 5

The focal spot-to-table distance in mobile fluoroscopy must

A
be at least 15 inches.
B
not exceed 15 inches.
C
be at least 12 inches.
D
not exceed 12 inches.

Gonadal shielding should be provided for male patients in which of the following examinations?

Femur
Abdomen
Pelvis

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

Which of the following is (are) likely to improve image quality and decrease patient dose?

Beam restriction
Low kilovolt and high milliampere- second factors
Grids

A
1 only
B
1 and 3 only
C
2 and 3 only
D
1, 2, and 3

Radiation safety requirements for fluoroscopic equipment include the following:
1. SSD at least 38 cm on stationary (fixed) equipment.
2. SSD at least 30 cm on mobile equipment.
3. high level/boost mode must have continuous audible signal.

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

To radiograph an infant for suspected free air within the abdominal cavity, which of the following projections of the abdomen will demonstrate the condition with the least patient exposure?

A
PA erect with grid
B
Left lateral decubitus with grid
C
Left lateral decubitus without grid
D
Recumbent AP without grid

All the following have an effect on patient dose except

A
kilovoltage
B
milliampere-seconds
C
focal spot size
D
inherent filtration

Which of the following is (are) associated with Compton scattering?

1. High-energy incident photons
2. Outer-shell electrons
3. Characteristic radiation

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

The most efficient type of male gonadal shielding for use during fluoroscopy is

A
flat contact
B
shaped contact (contour)
C
shadow
D
cylindrical

What is the approximate entrance skin exposure (ESE) for the average anteroposterior (AP) supine abdomen radiograph?

A
300 rad
B
300 mrad
C
35 rad
D
35 mrad

Which of the following would be the safest interval of time for a fertile woman to undergo abdominal radiography without significant concern for irradiating a recently fertilized ovum?

A
The first 10 days following the cessation of menstruation
B
The first 10 days following the onset of menstruation
C
The 10 days preceding the onset of menstruation
D
About 14 days before menstruation

An increase of 1.0 mm added aluminum filtration of the x-ray beam would have which of the following effects?

Increase in average energy of the beam
Increase in patient skin dose
Increase in milliroentgen output

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

The automatic exposure device that is located immediately under the x-ray table is the

A
ionization chamber
B
scintillation camera
C
photomultiplier
D
photocathode

If the exposure rate to an individual standing 4.0 m from a source of radiation is 10 mR/h, what will be the dose received after 20 minutes at a distance of 6 m from the source?

A
22.5 mR
B
7.5 mR
C
4.44 mR
D
1.48 mR

Which of the following terms is correctly used to describe x-ray beam quality?

A
mA
B
HVL
C
Intensity
D
Dose rate

At least how many HVLs are required to reduce the intensity of a beam of monoenergetic photons to less than 10% of its original value?

A
2
B
3
C
4
D
5

All of the following device(s) are generally used to help reduce patient dose, except

grid
collimator
gonad shield

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

If a patient received 4,500 mrad during a 6-minute fluoroscopic examination, what was the dose rate?

A
0.75 rad/min
B
2.7 rad/min
C
7.5 rad/min
D
27 rad/hr

Guidelines for the use of protective shielding state that gonadal shielding should be used

if the patient has reasonable reproductive potential
when the gonads are within 5 cm of the collimated field
when tight collimation is not possible

A
1 only
B
1 and 2 only
C
1 and 3 only
D
2 and 3 only

Which of the following groups of exposure factors will deliver the least patient dose?

A
300 mA, 250 ms, 70 kVp
B
300 mA, 125 ms, 80 kVp
C
400 mA, 90 ms, 80 kVp
D
600 mA, 30 ms, 90 kVp

Which of the following methods can be used to reduce radiation exposure to a recently fertilized ovum?

Elective booking
Patient questionnaire
The 10-day rule

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

All of the following have an effect on patient dose except

A
inherent filtration.
B
added filtration.
C
SID.
D
focal spot size.

Classify the following tissues in order of increasing radiosensitivity

Liver cells
Intestinal crypt cells
Muscle cells

A
1, 3, 2
B
2, 3, 1
C
2, 1, 3
D
3, 1, 2

Which of the following functions to protect the x-ray tube and the patient from overexposure in the event that the phototimer fails to terminate an exposure?

A
Circuit breaker
B
Fuse
C
Backup timer
D
Rheostat

Which of the following will produce the most significant increase in patient dose?

A
Decreased mAs
B
Decreased SID
C
Increased filtration
D
Increased kVp

Which of the following is most likely to result in the greatest increase in patient exposure?

A
Changing from a 400 speed system to a 200 speed system
B
Increasing kVp 15% and cutting mAs in half
C
Using two tomographic cuts instead of two plain images
D
From nongrid technique to 8:1 grid

Lateral deviation of the nasal septum may be best demonstrated in the

A
lateral projection
B
PA axial (Caldwell method) projection
C
parietoacanthal (Waters method) projection
D
AP axial (Towne method) projection

Reducing the number of repeat images is an important way to decrease patient exposure and can be accomplished by
1. good patient communication.
2. accurate positioning skills.
3. using AEC.

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

The principal function of filtration in the x-ray tube is to reduce

A
patient skin dose
B
operator exposure
C
scattered radiation
D
image noise

Inherent and added filtration in the x-ray tube functions to

A
reduce patient skin dose.
B
shorten the scale of contrast.
C
reduce scattered radiation.
D
soften the x-ray beam.

Patient dose during fluoroscopy is affected by the

distance between the patient and the input phosphor
amount of magnification
tissue density

A
1 only
B
3 only
C
2 and 3 only
D
1, 2, and 3

From which of the following primary beam sizes, all other factors remaining constant, will the greatest radiation exposure result?

A
8 × 10
B
10 × 12
C
11 × 14
D
14 × 17

Which of the following groups of exposure factors will deliver the least amount of exposure to the patient?

A
400 mA, 0.25 second, 100 kVp
B
600 mA, 0.33 second, 90 kVp
C
800 mA, 0.5 second, 80 kVp
D
800 mA, 1.0 second, 70 kVp

Which of the following safeguards is (are) taken to prevent inadvertent irradiation in early pregnancy?

Patient postings
Patient questionnaire
Elective booking

A
1 and 2 only
B
1 and 3 only
C
2 and 3 only
D
1, 2, and 3

A fluoroscopic examination requires 3 minutes of exposure on time. If the exposure rate for the examination is 250 mR/hr, what is the approximate exposure for the three minute procedure?

A
83.3 R
B
83.3 mR
C
12.5 R
D
12.5 mR

The largest amount of diagnostic x-ray absorption is most likely to occur in which of the following tissues?

A
Lung
B
Adipose
C
Muscle
D
Bone

The measure of the rate at which energy is transferred from ionizing radiation to soft tissue is termed

A
the characteristic effect
B
Compton scatter
C
linear energy transfer
D
the photoelectric effect

The primary function of filtration is to reduce

A
patient skin dose.
B
operator dose.
C
image noise.
D
scattered radiation.

With milliamperes (mA) increased to maintain output intensity, how is the ESE affected as the source-to-skin distance (SSD) is increased?

A
The ESE increases.
B
The ESE decreases.
C
The ESE remains unchanged.
D
ESE is unrelated to SSD.

Which of the following is (are) important for patient protection during fluoroscopic procedures?
1. Intermittent fluoroscopy
2. Fluoroscopic field size
3. Focus-to-table distance

A
1 and 2 only
B
1 and 3 only
C
2 and 3 only
D
1, 2, and 3

Filters used in radiographic x-ray tubes generally are composed of

A
aluminum
B
copper
C
tin
D
lead

Which of the following interactions between x-ray photons and matter involves a high-energy photon and the ejection of an outer shell electron?

A
Photoelectric effect
B
Coherent scatter
C
Compton scatter
D
Pair production

The primary function of filtration is to reduce

A
patient skin dose
B
operator dose
C
image noise
D
scattered radiation

A minimum total amount of aluminum filtration (inherent plus added) of 2.5 mm is required in equipment operated

A
above 50 kVp
B
above 60 kVp
C
above 70 kVp
D
above 80 kVp

Which of the following would be most likely to cause the greatest skin dose (ESE)?

A
Short SID
B
High kilovoltage
C
Increased filtration
D
Increased milliamperage

In which of the following examinations would a cassette front with very low absorption properties be especially important?

A
Abdominal radiography
B
Extremity radiography
C
Angiography
D
Mammography

The recommendation of "elective booking" states that elective abdominal radiographic examinations on women of reproductive age should be limited to the

A
10 days following the menses.
B
10 days following the onset of menses.
C
10 days before the onset of menses.
D
last 10 days of the menstrual cycle.

Methods of reducing radiation exposure to patients and/or personnel include
1. beam restriction.
2. shielding.
3. high-kV, low-mAs factors.

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

The reduction in x-ray photon intensity as the photon passes through a material is termed

A
absorption.
B
scattering.
C
attenuation.
D
divergence.

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 radiographic density 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.

All the following function to reduce patient dose except

A
beam restriction
B
high kVp, low mAs factors
C
a high-ratio grid
D
a high-speed imaging system

Types of structural damage to a DNA molecule by ionizing radiation include which of the following?

single-side-rail scission
double-side-rail scission
cross-linking

A
1 only
B
2 only
C
1 and 2 only
D
1, 2, and 3

It is necessary to question a female patient of childbearing age regarding her

date of last menstrual period
possibility of being pregnant
age at her first pregnancy

A
1 only
B
1 and 2 only
C
1 and 3 only
D
2 and 3 only

Replacing 200-speed intensifying screens with 400-speed screens will

require the exposure to be cut in half.
enable the radiographer to decrease the exposure time.
increase the production of scattered radiation.

A
1 only
B
1 and 2 only
C
1 and 3 only
D
1, 2, and 3

A test radiograph like the one pictured in Figure A would be made by the radiation safety officer (RSO) or equipment service person and is used to evaluate

Figure A. Courtesy of Stamford Hospital, Department of Radiology

A
focal spot size.

B
linearity.

C
collimator alignment.

D
spatial resolution.

The SSD in mobile fluoroscopy must be

A
a minimum of 15 in.
B
a maximum of 15 in.
C
a minimum of 12 in.
D
a maximum of 12 in.

The reduction in the intensity of an x-ray beam as it passes through material is termed

A
absorption
B
scattering
C
attenuation
D
divergence

The interaction between x-ray photons and tissue that is responsible for radiographic contrast but that also contributes significantly to patient dose is

A
the photoelectric effect
B
Compton scatter
C
coherent scatter
D
pair production

Which of the following contributes most to patient dose?

A
The photoelectric effect
B
Compton scatter
C
Classic scatter
D
Thompson scatter

For radiographic examinations of the skull, it is generally preferred that the skull be examined in the

A
AP projection
B
PA projection
C
recumbent position
D
supine position

It is essential to question female patients of childbearing age regarding the

date of their last menstrual period
possibility of their being pregnant
number of x-ray examinations they have had in the past 12 months

A
1 only
B
1 and 2 only
C
1 and 3 only
D
1, 2, and 3

Aluminum filtration has its greatest effect on

A
low-energy x-ray photons
B
high-energy x-ray photons
C
low-energy scattered photons
D
high-energy scattered photons

The focal spot-to-table distance, in mobile fluoroscopy, must be

A
a minimum of 15 inches.
B
a maximum of 15 inches.
C
a minimum of 12 inches.
D
a maximum of 12 inches.

If a patient received 2000 mrad during a 10-minute fluoroscopic examination, what was the dose rate?

A
0.02 rad/min
B
0.2 rad/min
C
2.0 rad/min
D
20 rad/min

Which of the following groups of exposure factors would deliver the lowest patient dose?

A
2.5 mAs, 100 kVp, 400-speed screens
B
10 mAs, 90 kVp, 200-speed screens
C
10 mAs, 70 kVp, 800-speed screens
D
10 mAs, 80 kVp, 400-speed screens

Patient exposure can be minimized by using which of the following?
1. Accurate positioning
2. High-kV, low-mAs factors
3. Rare earth screens

A
1 only
B
1 and 2 only
C
1 and 3 only
D
1, 2, and 3

Types of gonadal shielding include which of the following?

Flat contact
Shaped contact (contour)
Shadow

A
1 only
B
1 and 2 only
C
2 and 3 only
D
1, 2, and 3

If the entrance dose for a particular radiograph is 320 mR, the radiation exposure at 1 m from the patient will be approximately

A
32 mR.
B
3.2 mR.
C
0.32 mR.
D
0.032 mR.