Mosby 7th edition Challenge test 3

No procedures questions

Radiation that exits the x-ray tube from the anode is called:

a. Remnant radiation

b. Gamma radiation

c. Nonionizing radiation

d. Primary radiation

D. Remnant radiation exits the body (choice A); gamma radiation is not produced in the x-ray tube (choice B). Choice C, nonionizing radiation, is incorrect because x-rays are ionizing radiation.

The photon-tissue interaction in diagnostic radiography that results in the total absorption of an x-ray photon and the production of contrast in the radiographic image is:

a. Compton

b. Coherent

c. Photoelectric

d. Pair production

C. Choice A is incorrect because Compton produces scatter radiation. Choice B is incorrect because coherent scatter is produced at extremely low kVp levels. Choice D is incorrect because p

Which photon-tissue interaction produces a recoil electron and a scattered photon in diagnostic radiography?

a. Compton

b. Coherent

c. Photoelectric

d. Pair production

A. Choice B is incorrect because coherent scatter occurs at extremely low kVp levels and does not produce a recoil electron. Choice C is incorrect because the photoelectric effect does not scatter the photon. Choice D is incorrect because pair production does not occur in diagnostic radiography

The SI unit of exposure in air is the:

a. Air kerma

b. Gray

c. Becquerel

d. Sievert

A

The SI unit of absorbed dose is the:

a. LET

b. Gray

c. Curie

d. Sievert

B

The SI unit of equivalent dose is the:

a. Sievert

b. Gray

c. Radiation weighting factor

d. LET

A

The SI unit of effective dose is the:

a. Sievert

b. Gray

c. Radiation weighting factor

d. LET

A

The SI unit of radioactivity is the:

a. Becquerel

b. Gray

c. Quality factor

d. Curie

A

________ refers to energy per unit mass absorbed by an object.

a. Bq

b. Gya

c. WR

d. Gyt

D. The t refers to tissue.

The amount of radiation deposited per unit length of tissue traversed by incoming photons is called:

a. REM

b. RADS

c. LET

d. RPU

C. Linear energy transfer

The weighting factor related to radiation effects in organs and tissues is:

a. WR

b. Gya

c. Gyt

d. WT

A

Compton interaction:

a. Produces poorer recorded detail in the radiographic image

b. Results in absorption of the incident photon

c. May produce higher contrast on the radiograph

d. May produce a gray fog on the image, lowering contrast

D. Choice A is incorrect because contrast is produced by photoelectric effect, not Compton interaction

The radiation weighting factor for x-rays is:

a. 10

b. 1

c. 20

d. 5

B

Mutations are examples of:

a. Short-term somatic effects

b. Genetic effects

c. Acute radiation syndrome

d. Long-term somatic effects

B. Genetic effects may express themselves in future generations as mutations.

Effective dose limit is:

a. The level of radiation that an organism can receive before formation of cancer

b. Age × 1 mSv for occupationally exposed individuals

c. 50 mSv per month for occupationally exposed individuals

d. 50 mSv per year for occupationally exposed individuals

D. Be sure to know all the dose limits

What agency publishes radiation protection recommendations?

a. ICRP

b. NCRP

c. NRC

d. ASRT

B. National Council on Radiation Protection and Measurements. Choice A, the International Commission on Radiological Protection, is incorrect. Choice C is incorrect, but the Nuclear Regulatory Commission does have enforcement power. Choice D is incorrect because the American Society of Radiologic Technologists is the professional organization for radiation science professionals.

Radiation safety standards assume what relationship between dose and response?

a. Linear-threshold

b. Nonlinear-nonthreshold

c. Linear-nonthreshold

d. Nonlinear-threshold

C. Choices A and D are incorrect because there is no threshold dose regarding radiation protection. Choice B is incorrect because we do not assume a nonlinear response for radiation protection

Which of the following would be applicable to radiation therapy?

a. Inverse square law

b. Law of Bergonié and Tribondeau

c. Reciprocity law

d. Ohm’s law

B. Choice A is incorrect because the inverse square law states that the intensity of radiation is inversely proportional to the square of the distance from the source of radiation. Choice C is incorrect because the reciprocity law states that mAs = mAs. Choice D is incorrect because Ohm’s law states that voltage is equal to current times resistance in a circuit

Which of the following causes about 5% of the cellular response to radiation?

a. Direct effect

b. Law of Bergonié and Tribondeau

c. Target theory

d. Indirect effect

A. Indirect effect occurs when radiation strikes the cytoplasm. This causes the formation of free radicals and hydrogen peroxide, which damage the cell. Choice B is incorrect because the law of Bergonié and Tribondeau describes the radiosensitivity of cells. Choice C is incorrect because target theory explains that DNA is the master molecule of the cell. Choice D is incorrect because indirect effect causes about 95% of the cellular response.

When radiation strikes the cytoplasm, which of the following occurs?

a. Direct effect

b. Law of Bergonié and Tribondeau

c. Target theory

d. Indirect effect

D. Direct effect occurs when radiation directly hits the cellular nucleus. Indirect effect occurs when radiation strikes the cytoplasm of the cell.

The equivalent dose limit for the embryo-fetus is:

a. 500 mSv per year

b. 0.5 mSv per month

c. 0.05 rem per month

d. 0.5 mSv during gestation

B

The effective dose limit for radiographers for localized areas of skin is:

a. 50 mSv per year

b. 500 mSv per year

c. 0.5 mSv monthly

d. 10 mSv monthly

B

The cumulative occupational exposure for a 48-yearold radiographer is:

a. 48 mSv

b. 480 mSv

c. 24 mSv

d. 0.48 mSv

B

The annual effective dose limit for the general public, assuming infrequent exposure, is:

a. 5 mSv

b. 500 mSv

c. 0.5 mSv

d. 50 mSv

A

The upper boundary dose that can be absorbed that carries a negligible risk of somatic or genetic damage to the individual defines:

a. Maximum permissible dose

b. ALARA

c. Law of Bergonié and Tribondeau

d. Effective dose limit

D. Choice A is incorrect because this term is no longer used. Choice B is incorrect because ALARA stands for as low as reasonably achievable.

Compared with OSL and TLD badges, film badges are:

a. more sensitive

b. less sensitive

c. the same sensitivity

C

The exposure switch on a portable x-ray machine must be attached to a cord that is at least how many feet long?

a. 3

b. 6

c. 12

d. 2

B. The exposure switch on a portable x-ray machine must be attached to a cord that is at least 6 feet long. This does NOT mean six feet is a safe distance. A lead apron must still be worn when performing mobile radiography

Under what conditions can the radiographer be exposed to the primary beam?

a. When performing mobile radiography, as long as the exposure is low

b. Never, under any conditions

c. When performing cross-table projections, if needed to hold the cassette in place

d. When assisting with fluoroscopy

B. Under no circumstances should the radiographer be exposed to the primary beam

For purposes of radiation protection, the x-ray beam is filtered. X-ray tubes operating above 70 kVp must have total filtration of:

a. At least 0.25-mm aluminum equivalent

b. At least 0.25-mm lead equivalent

c. No more than 2.5-mm aluminum equivalent

d. At least 2.5-mm aluminum equivalent

D. For proper radiation protection, x-ray tubes operating above 70 kVp must have total filtration of at least 2.5-mm aluminum equivalent. Lead is not used as a filter material.

Gonadal shielding should be used:

a. On every examination performed

b. Whenever it does not obstruct the area of clinical interest

c. Only on children and women of childbearing age

d. Only during pregnancy

B. Choice A is incorrect because gonadal shielding may obstruct the area of interest in some projections. Choice C is incorrect because male patients must also be shielded. Choice D is incorrect because the gonads must be protected outside of pregnancy as well

The secondary protective barrier must overlap the primary protective barrier by at least:

a. 1 ⁄10 inch

b. 1 inch

c. 1 foot

d. ½ inch

D. The secondary protective barrier must overlap the primary protective barrier by at least ½ inch to prevent leakage after the building has settled.

The x-ray control booth is considered a:

a. Secondary protective barrier

b. Primary protective barrier

c. Mobile barrier

d. Nonbarrier

A. The primary beam is never aimed at the control booth. The exposure switch in the x-ray control booth must have a cord short enough that the radiographer has to be behind the secondary protective barrier to operate the switch.

The exposure switch must keep the radiographer behind the:

a. Primary protective barrier

b. Secondary protective barrier

c. X-ray tube

d. Door

B. The exposure switch in the x-ray control booth must have a cord short enough that to operate the switch, the radiographer must be in the control booth, not simply behind the x-ray tube. The control booth is a secondary, not a primary, protective barrier.

Areas for the general public, such as waiting rooms and stairways, are considered:

a. Controlled areas

b. Uncontrolled areas

c. Off-limits areas

d. Radiation areas

B. Waiting rooms and stairways are considered uncontrolled areas. They are shielded to keep exposure under 0.5 rem annually. Controlled areas are those occupied by persons who are trained in radiation safety and are wearing personnel monitoring devices. There is no specific area known as the off-limits area or the radiation area

An uncontrolled area must be kept under what dose weekly?

a. 5 μSv

b. 10 μSv

c. 15 μSv

d. 20 μSv

D

Areas occupied by persons trained in radiation safety and wearing personnel monitoring devices are called:

a. Controlled areas

b. Uncontrolled areas

c. Off-limits areas

d. Radiation areas

A. Controlled areas are those occupied by persons who are trained in radiation safety and are wearing personnel monitoring devices. Uncontrolled areas are general public areas, such as stairways and waiting rooms. There is no specific area known as the offlimits area or the radiation area.

Which of the following takes into account the volume and types of examinations performed in the room?

a. Use factor

b. Shielding factor

c. Volume factor

d. Workload

D. Workload, measured in mA minutes per week, takes into account the volume and types of exams performed in the room. The use factor is the amount of time the beam is on and directed at a particular barrier. There is no specific shielding factor.

How is workload factor measured?

a. Half-value layer

b. Amount of time the beam is on

c. mA minutes per week

d. Average kVp per week

C. Workload, measured in mA minutes per week, takes into account the volume and types of exams performed in the room. Half-value layer is the thickness of absorbing material required to reduce the x-ray beam to half its original intensity. The amount of time the beam is on and directed at a particular barrier is called the use factor.

The amount of time the beam is on and directed at a particular barrier is called:

a. Use factor

b. Shielding factor

c. Occupancy

d. Workload

A. The amount of time the beam is on and directed at a particular barrier is called the use factor. Workload, measured in mA minutes per week, takes into account the volume and types of exams performed in the room. Occupancy is a determinant of barrier thickness that simply takes into account who occupies a given area. There is no specific shielding factor. Be sure to review the determinants of barrier thickness factors

Leakage radiation from a diagnostic x-ray tube may not exceed:

a. 1 mGya per hour, measured at the source

b. 10 mGya per hour

c. 1 mGya per hour, measured at 1 m from the housing

d. 100 mGya per hour, measured at 1 m from the housing

C. It is measured at a distance of 1 meter because that is where the patient would be.

Organelles are located in the:

a. DNA

b. Cytoplasm

c. RNA

d. Cellular nucleus

B. The cytoplasm contains water and the organelles, each of which plays a role in the functioning of the cell.

Relative biological effectiveness (RBE) describes the:

a. Ability of radiation to produce biological damage

b. Efficacy of radiation therapy

c. Sensitivity of DNA to radiation exposure

d. Radiosensitivity of water in the cytoplasm

A. RBE varies with the type of radiation and its LET.

The law of Bergonié and Tribondeau states:

a. Radiation intensity is inversely proportional to the square of the distance

b. Cells are most sensitive to radiation when they are immature, undifferentiated, and rapidly dividing

c. Voltage is equal to current times resistance

d. All radiation exposure causes damage to the cell

B. A is the inverse square law; C is Ohm’ law.

Which of the following describes the radiosensitivity of lymphocytes?

a. Low radiosensitivity

b. Least radiosensitive cells in the body

c. Most radiosensitive cells in the body

d. There is no connection between lymphocytes and radiation exposure

C. Muscle cells are the least radiosensitive cells in the body

When are embryologic effects least likely to occur?

a. During the final trimester of gestation

b. During the middle trimester of gestation

c. During the first trimester of gestation

d. At conception

A. However, following ALARA at all times is of paramount importance. Embryologic effects are most likely to occur during the first trimester.

Lead aprons must be worn to protect against which photon–tissue interaction?

a. Compton

b. Coherent

c. Photoelectric interaction

d. Pair production

A. This should be the only source of occupational exposure.

What is plotted on the x-axis of a dose-response curve?

a. Dose

b. Response

c. Receptor exposure

d. Radioactivity

A

What is the preferred source-to-skin distance for C-arms?

a. 12 inches

b. 10 inches

c. 20 inches

d. 15 inches

D. The requirement is no less than 12 inches

Photoelectric interaction occurs at what level in the atom?

a. L-shel

b. K-shell

c. M-shel

d. Outer shell

B

Radiation exiting the patient in very divergent paths would be indicative of

a. Photoelectric rays

b. Scatter

c. Coherent interaction

d. Patient motion during the exposure

B

Cellular components contained in the cytoplasm are called

a. Free radicals

b. Ions

c. Organelles

d. DNA strands

C

Long-wavelength x-rays are removed from the primary beam by the use of a

a. Collimator

b. Filter

c. Cylinder cone

d. Gonadal shield

B. The filter is made of aluminum.

The primary purpose of radiation safety practices is to

a. Limit occupational exposure

b. Limit the introduction of mutations into the population

c. Limit long-term somatic effects

d. Limit short-term somatic effects

B

Devices in the x-ray circuit that increase or decrease voltage are called:

a. Rectifiers

b. Generators

c. Timers

d. Transformers

D

The filament circuit makes use of what type of transformer?

a. Step-up

b. Autotransformer

c. Step-down

d. Falling load

C

Because the x-ray tube requires DC to operate properly, what device is required in the x-ray circuit?

a. Autotransformer

b. Step-up transformer

c. Rectifier

d. Falling load generator

C

Where is the rectifier located in the x-ray circuit?

a. Between the timer and the step-up transformer

b. Between the step-up transformer and the stepdown transformer

c. Between the primary and secondary coils of the step-up transformer

d. Between the step-up transformer and the x-ray tube

D

Thermionic emission occurs at the:

a. Anode

b. Control panel

c. Rectifier

d. Cathode

D

At the time of exposure, the charge on the focusing cup is:

a. Irrelevant

b. Positive

c. Negative

d. Alternating

C. This is to repel the electrons.

An interaction that produces heat at the anode and also produces x-rays is called:

a. Characteristic

b. Photoelectric

c. Compton

d. Bremsstrahlung

D

When a quality control test for exposure linearity is performed, adjacent mA stations must be within ________ of one another.

a. 2% of SID

b. 4%

c. 10%

d. 5%

C

When a quality control test for exposure reproducibility is performed, successive exposures must be within ________ of one another.

a. 2% of SID

b. 4%

c. 10%

d. 5%

D

When a quality control test for collimator accuracy is performed, the result must be within ________.

a. 2% of SID

b. 4%

c. 10%

d. 5%

A

When a quality control test for accuracy of kVp is performed, the result must be within ________ of the control panel setting.

a. 2% of SID

b. 4%

c. 10%

d. 4

C

The accuracy of collimation at a 72-inch SID must be:

a. ± 1.44 inches

b. ± 7.2 inches

c. ± 3.6 inches

d. ± 0.02 inch

A. 2% of the SID

The feature of the image intensifier that ensures the radiation dose striking the input phosphor is constant is the:

a. Photocathode

b. Electron focusing lens

c. Automatic brightness control

d. Vidicon tube

C

Instead of Vidicon or Plumbicon tubes, what device may be used in the television system?

a. Charge-coupled device (CCD)

b. C-arm

c. Automatic brightness control

d. Output phosphor

A

The electronic device that may be used for many quality control tests on x-ray equipment is the:

a. Automatic exposure control

b. Digital dosimeter

c. Penetrometer

d. Densitometer

B

The smallest particle of a compound that retains the characteristics of the compound is a(n):

a. Element

b. Atom

c. Molecule

d. Neutron

C

Given an original technique of 20 mAs and 80 kVp, which of the following would produce a radiograph with double the IR exposure?

a. 40 mAs, 90 kVp

b. 30 mAs, 92 kVp

c. 40 mAs, 80 kVp

d. 15 mAs, 92 kVp

C

Distance and density are governed by what law or rule?

a. Reciprocity law

b. 15% rule

c. Inverse square law

d. Density maintenance rule

C

Unwanted markings on a radiographic image are called:

a. Processing irregularities

b. Processing artifacts

c. Artifacts

d. Plus-density markings

C

Manual manipulation of the digital image after acquisition is referred to as:

a. Digital coding

b. Postprocessing

c. Leveling

d. Archiving

B. Be familiar with the various modes of postprocessing.

As speed class decreases, patient dose:

a. Increases

b. Decreases

c. Remains the same

A

Because the digital system software ultimately controls contrast, kVp may be:

a. Increased

b. Decreased

c. Kept the same

A. Patient dose may be lower.

Image acquisition, image display, and image storage are the primary components of what system?

a. DICOM

b. CR/DR

c. PACS

d. HIS

C

What “language” is used by PACS?

a. DICOM

b. Base 10

c. HIS

d. RIS

A. Digital communication in medicine

Which exposure factor causes excessive image noise if set too high?

a. kVp

b. mAs

c. AEC

d. Time

A. Too few photons creating the image

Which of the following can be documented as an indication of patient dose?

a. AEC

b. Exposure indicator

c. System speed class

d. Histogram

B

Choosing the anatomic region on a touch screen display to set technique is called:

a. Phototiming

b. Anatomically programmed radiography

c. AEC imaging

d. Automatic radiography

B

What is used to reduce both patient dose and the production of scatter radiation?

a. Grids

b. High speed class

c. Collimation

d. Filtration

C

Image artifacts are usually classified as:

a. Scatter

b. Plus or minus density

c. Compton and photoelectric

d. Patient motion and equipment motion

B

Grid ratio is expressed as:

a. Length of the lead strips to the space between them

b. Height of the aluminum strips to the space between them

c. Height of the interspacers to the lead strips

d. Height of the lead strips to the space between them

D. H/D

The primary type of grid used in diagnostic imaging is:

a. Crosshatch

b. Parallel

c. Rhombic

d. Focused

D

Which of the following does not belong in the definition of matter?

a. Travels at the speed of light

b. Has shape

c. Has form

d. Occupies space

A

The accuracy of collimation at a 60-inch SID must be:

a. ± 6 inches

b. ± 3 inches

c. ± 2 inches

d. ± 1.2 inches

D. 2% of the SID

Which of the following is true regarding frequency and wavelength of electromagnetic radiation?

a. Frequency and wavelength are directly proportional

b. Frequency and wavelength are unrelated

c. Wavelength and frequency are inversely proportional to the square of the distance between wave crests

d. Wavelength and frequency are inversely proportional

D. Be sure to read all choices carefully

Beam restrictors reduce the amount of scatter produced by reducing which of the following?

a. Characteristic rays

b. Photoelectric effect

c. Compton interactions

d. Pair production

C

What effect does increasing filtration have on contrast?

a. Increases contrast

b. Decreases contrast

c. No effect

d. Varying effect

B. The average wavelength of the beam decreases

Decreased SID causes image:

a. Minification

b. Foreshortening

c. Elongation

d. Magnification

D

Inaccurate use of grids may result in repeat exposures due to what condition?

a. Overexposure

b. Grid analysis error

c. Underexposure

d. Cut-of

D

The measure of a grid’s ability to enhance contrast is called:

a. Grid ratio

b. Grid selectivity

c. Speed

d. Contrast improvement factor

D

Which of the following grid errors would result in an image that shows normal exposure in the middle but decreased exposure on the sides, assuming the correct side of the grid faces the x-ray tube?

a. Upside down

b. Off-level

c. Lateral decentering

d. Grid-focus decentering

D

Which of the following grid errors would result in an image that shows decreased density more to one side than the other?

a. Upside down

b. Off-level

c. Lateral decentering

d. Grid-focus decentering

B

Grid ratio is described by which of the following?

a. H & D

b. H/D

c. mAs = mAs

d. 15% rule

B

Grid radius is described as:

a. The height of the lead strips divided by the distance between the lead strips

b. The distance between the lead strips divided by the height of the lead strips

c. The number of lead strips per inch or centimeter

d. The SID at which the grid may be used

D

Structures seen outside of the collimated area on a radiograph, produced by “off-focus” (extrafocal) radiation, are the result of:

a. Electron interaction within the x-ray tube at a point other than the focal spot

b. Scatter radiation emanating from the patient or tabletop

c. The use of an SID that is not recommended with the grid in use

d. The x-ray tube positioned off-center to the grid

A

Geometric unsharpness within the radiographic image can be minimized by using the:

1. Smallest focal spot

2. Shortest object-image receptor distance

3. Longest target-image receptor distance

a. 1 and 2 only

b. 1 and 3 only

c. 2 and 3 only

d. 1, 2, and 3

D

An undistorted radiographic image results when the object plane and the image plane are:

a. Angled in relation to each other

b. At right angles

c. Parallel

d. Perpendicular

C

A radiographic grid should be used when:

1. The body area to be radiographed measures more than 10 cm

2. A field size larger than 10 to 12 inches is used

3. More than 60 kVp is required to penetrate a body part

a. 1 and 2 only

b. 1 and 3 only

c. 2 and 3 only

d. 1, 2, and 3

D