Deck 15: Radiation Safety and Production of X-Rays

Question 1

Chronic radiation exposure occurs when:

A) large doses of radiation are received over a short time period
B) large doses of radiation are received over a long time period
C) small doses of radiation are received over a short time period
D) small doses of radiation are received over a long time period

Answer 1

small doses of radiation are received over a long time period

Question 2

Which controls the penetrating power of the x-ray beam?

A) Exposure timer
B) Kilovoltage selector
C) Milliampere selector
D) Master switch

Answer 2

Kilovoltage selector

Question 3

A lead apron and a thyroid collar:

A) are used for a full-mouth series of films but are not necessary for single periapical films
B) must be used on all patients for all exposures
C) are required for pediatric patients but are optional for adults
D) are mandated only for pregnant women

Answer 3

must be used on all patients for all exposures

Question 4

Damage to which cells could lead to genetic mutations?

A) Bone marrow and blood vessel
B) Ovarian and sperm
C) Neural and connective tissue
D) Skin and muscle tissue

Question 5

Which measure protects against occupational exposure to radiation?

A) Always wear a film badge (pocket dosimeter) at work
B) Wear a lead apron if holding the film in place by hand, for a small child
C) Never stand closer than 3 feet from the x-ray unit during an exposure
D) Stand at a straight angle (180 degrees) to the beam

Question 6

The lead collimator:

A) absorbs heat produced in the generation of the primary beam
B) restricts the size and shape of the primary beam
C) removes long wavelengths of the primary beam
D) stops production of the primary beam

Question 7

Radiographic density is controlled by the:

A) low-voltage circuit
B) peak kilovoltage (kVp) setting
C) milliamperes (mA) setting
D) position indicator device (PID)

Question 8

X-ray wavelengths with the greatest energy and usefulness are:

A) shorter
B) longer
C) more ionized
D) straighter

Question 9

Which component of the x-ray machine functions in positioning the tubehead?

A) Kilovoltage selector
B) Control panel
C) Extension arm
D) Cathode

Question 10

Which best describes the latent period?

A) Long period of time over which small doses of radiation are repeatedly absorbed
B) Large dose of radiation, absorbed in a short period of time
C) Lapse of time from x-ray exposure until noticeable damage
D) Accumulation of damage from x-ray exposure over a lifetime

Question 11

Which tissue has the highest radiation sensitivity?

A) Small lymphocytes
B) Salivary gland tissue
C) Kidney tissue
D) Muscle tissue

Question 12

If the tubehead drifts, which component of the x-ray machine needs attention?

A) Cathode
B) Extension arm
C) Control panel
D) Collimator

Question 13

Dental radiographs are NOT used for:

A) detection of dental caries in the early stages
B) identification of early stages of bone loss
C) evaluation of growth and development
D) detection of soft tissue trauma

Question 14

Damage from ionizing x-radiation to genetic cells:

A) affects only the person exposed
B) can affect future generations
C) affects only the dental assistant
D) affects the cells of the eyes, skin, and oral mucosa

Question 15

Which structure appears radiopaque on dental x-ray film?

A) Metal restorations
B) Soft tissue
C) Tooth decay
D) Dental pulp

Question 16

Which is the heart of the x-ray generating system?

A) The x-ray tube
B) An insulating oil
C) A transformer
D) The position indicator device

Question 17

Which radiation produces diagnostically useful radiographs?

A) Primary
B) Secondary
C) Scatter
D) Leakage

Question 18

If you change the exposure time of the x-ray unit, what is affected?

A) Energy of the beam
B) Wavelength of the x-rays
C) Number of x-rays produced
D) Penetrability of the x-rays

Question 19

Which term describes light or white areas on the radiograph?

A) Radiopaque
B) Radiolucent
C) Density
D) Contrast

Question 20

Which statement is NOT true of electromagnetic radiation?

A) It is made up of photons.
B) It travels at various speeds.
C) It differs only by wavelength.
D) It travels in straight lines.

Question 21

Radiation exposure is measured in SI units as coulombs per kilogram.

Question 22

The aluminum filter restricts the size of the x-ray beam and reduces patient exposure.

Question 23

Dental imaging:

A) refers only to film-based images
B) refers only to digitally produced images
C) detects conditions that might otherwise remain undetected
D) is harmless with modern digital imaging technology

Question 24

Electrons are generated in the x-ray tubehead at the cathode.

Question 25

If the tubehead drifts, the extension arm should be held by the assistant while the dentist exposes the x-ray.

Question 26

The dentist is responsible for prescribing or ordering dental radiographs for the patient and should evaluate each patient according to the patient's individual needs.

Question 27

The maximum permissible dose (MPD) is the amount of radiation that a patient may receive in 1 year.

Question 28

The function of the focusing cup is to aim the x-ray beam at the film in the patient's mouth and thereby minimize the amount of radiation to the patient's face.

Question 29

Any exposure to radiation, no matter how small an amount, has the potential to cause harmful biologic changes in the operator and the patient.

Question 30

An operator will know when the master switch is on because a black indicator light will also be on.

Question 31

Ionization is the harmful effect of x-rays, resulting in a disruption of cellular structure and permanent damage to living cells.

Question 32

Leakage radiation occurs when an x-ray is deflected from its path during impact with the patient.

Question 33

When in storage, the lead apron should be:

A) hung
B) folded
C) rolled
D) creased

Question 34

The position indicator device (PID) is lined with aluminum to absorb excess radiation.

Question 35

The oil in the x-ray tube absorbs about 99% of the energy; the other 1% exits the tubehead as x-rays that move toward the patient's mouth.

Question 36

The faster the speed of the film, the less radiation is needed for each exposure.

Question 37

Film speed is determined by the size of the crystals in the emulsion that coats the film.

Question 38

The dental assistant can hold the film for a patient who is in a wheelchair or who is disabled, during a radiographic exposure.

Question 39

The best way to limit exposure to a patient's hands and fingers is to:

A) have the patient use one finger only
B) use a film-holding device
C) have someone else hold the film
D) hold the film in place for the patient

Question 40

Which is NOT consistent with the ALARA principle?

A) Reducing the number of exposures
B) Minimizing retakes
C) Keeping exposure levels as low as possible
D) Exposing radiographs at predetermined intervals

Question 41

The term object-film distance (OFD) describes the distance between the teeth being radiographed and the radiographic film.

Question 42

The four factors that affect radiograph quality are contrast, time, film speed, and detail.

Question 43

The length of the PID determines the source-film distance. A shorter PID reduces distortion due to magnification.

Question 44

The image on a radiograph appears in a range from black to white with multiple shades of gray in between. The differences between the shades of gray are referred to as density.

Question 45

The Consumer Patient Radiation Health and Safety Act is a federal law that establishes guidelines for the proper maintenance of x-ray equipment and requires those taking dental radiographs to be properly trained and certified.