Deck 38: Foundations of Radiography, Radiographic Equipment, and Radiation Safety

Question 1

The component of the x-ray machine that functions in positioning the tubehead is the:

A)kilovoltage selector.
B)control panel.
C)extension arm.
D)cathode.

Answer 1

extension arm.

Question 2

In dentistry,the _____ the wavelengths of the x-rays,the greater their energy and their usefulness.

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

Answer 2

shorter

Question 3

One of the rules of radiation protection is never stand closer than _____ feet from the x-ray unit during an exposure unless you are behind a barrier.

A)2
B)6
C)10
D)15

Answer 3

6

Question 4

Which of the following statements is true concerning the structure of the atom?

A)The nucleus contains protons and electrons.
B)Electrons have no weight or mass.
C)The orbital path of an electron around the nucleus is called an electron shell.
D)Electrons are unstable in their orbits and shift freely.

Question 5

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 is optional for adults.
D)are mandated only for pregnant women.

Question 6

Which of the following tissues has the highest radiation sensitivity?

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

Question 7

The dentist who is credited with the first practical use of radiographs in dentistry in 1896 is:

A)Wilhelm Conrad Roentgen.
B)Edmund Kells.
C)John Greenwood.
D)G.V. Black.

Question 8

The uses of dental images include the detection of:

A)incipient occlusal lesions.
B)periodontal probing depths.
C)bone loss in its early stages.
D)percussion sensitivity as part of endodontic evaluation.

Question 9

Damage caused by ionizing x-radiation to genetic cells:

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

Question 10

The sharpness of a radiographic image can be improved by:

A)a larger focal spot size.
B)faster speed film.
C)smaller film crystal size.
D)movement of the patient.

Question 11

The term _____ is used to describe areas that appear dark on the image; _____ is the term used to describe areas that appear white or light gray.

A)radiopaque; radiolucent
B)radiolucent; radiopaque
C)density; contrast
D)contrast; density

Question 12

Exposure to radiation:

A)no matter how small, has the potential to cause harmful biologic changes.
B)has a threshold, below which exposure is entirely safe.
C)is safer when there is a single, large dose rather than a series of smaller doses.
D)from a dental x-ray machine does not involve particulate radiation and is completely safe.

Question 13

All of the following structures will appear radiolucent on dental x-ray film except:

A)metal restorations.
B)soft tissue.
C)tooth decay.
D)dental pulp.

Question 14

The range of shades of gray between black and white on an image is called:

A)contrast.
B)density.
C)sharpness.
D)focus point.

Question 15

Secondary radiation:

A)is often referred to as the useful beam.
B)is often referred to as the primary beam.
C)refers to x-radiation that is created when the primary beam interacts with matter.
D)is a form of radiation that occurs when an x-ray beam has been deflected from its path by interaction with matter.

Question 16

The heart of the x-ray generating system is the:

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

Question 17

The Guidelines for Prescribing Dental Radiographs issued by the American Dental Association and the FDA recommend which of the following dental imaging procedures for a pregnant patient?

A)Do not take images of a pregnant patient.
B)Radiographic imaging procedures do not need to be altered because of pregnancy.
C)Take images only after the first trimester.

Question 18

Anything that occupies space and has a form or shape is:

A)energy.
B)a solid.
C)matter.
D)a photon.

Question 19

The degree of density or blackness on an image is controlled by the:

A)low-voltage circuit.
B)kilovoltage.
C)milliampere seconds.
D)position indicating device.

Question 20

The x-ray was discovered on November 8,1895,by:

A)John Greenwood.
B)Wilhelm Conrad Roentgen.
C)Edmund Kells.
D)G.V. Black.

Question 21

The function of the filtration discs are used to _____ and are made of ______.

A)remove long wavelengths from the beam; aluminum
B)remove long wavelengths from the beam; copper
C)restrict the size of the beam; lead
D)restrict the size of the beam; aluminum

Question 22

Chronic radiation exposure occurs when _____ doses of radiation is received over a ____ time period.

A)large; short
B)large; long
C)small; short
D)small; long

Question 23

The fuzzy or blurred area around an image is called ____.It can be reduced by ____.

A)distortion; limiting movement
B)a penumbra; limiting movement
C)distortion; using fast film
D)a penumbra; using fast film

Question 24

The time lapse from x-ray exposure until noticeable damage occurs is known as:

A)the latent period.
B)chronic exposure.
C)the cumulative period.
D)none of the above.

Question 25

Thermionic emission refers to the:

A)release of electrons from the tungsten filament.
B)ions formed in the x-ray tube by the loss of electrons.
C)change in filament resistance due to heating.
D)slamming of electrons against the target.

Question 26

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 27

All the following are true of electromagnetic radiation except they:

A)are composed of photons that travel through space in waveforms.
B)travel at various speeds.
C)differ only by their wavelength.
D)travel in straight lines.

Question 28

How much filtration is federally required for a dental x-ray machine operating over 70 kVp?

A)2.75 mm
B)2.50 mm
C)2.25 mm
D)0.5 mm

Question 29

A(n)_____ is a minute bundle of energy that has no weight or mass.

A)ion
B)atom
C)photon
D)electron

Question 30

Because the entire x-ray area is considered a radiation hazard area,a radiation hazard sign must be posted in:

A)sight of patients.
B)sight of personnel.
C)the doctor's private office.
D)both a and b

Question 31

Heat is reduced from the target by:

A)insulating oil.
B)copper stem.
C) aluminum filter.
D) both a and b.
E) both b and c.

Question 32

The council that determines the radiation effects and levels tolerable for humans is the:

A)American Dental Association (Council on Radiation Safety).
B)American Dental Association (Council on Dental Materials).
C)National Council on Radiation Protection and Measurements.
D)All of the above are correct.

Question 33

Damage to which type of cell is passed on to future generations?

A)Somatic cell
B)Genetic cell
C)Either somatic or genetic cells
D)Neither somatic cells nor genetic cells

Question 34

Dental imaging:

A)refers to film-based images.
B)refers to digitally produced images.
C)detects conditions that might otherwise remain undetected.
D)is all of the above.

Question 35

The penetrating power of the x-ray beam is controlled by the settings on the:

A)impulse timer.
B)kilovolt setting.
C)milliamp setting.
D)All of the above are correct.

Question 36

The lead collimator is used to:

A)make the primary beam more accurate
B)restrict the size and shape of the primary beam.
C)remove long wavelengths.
D)stop production of the primary beam.

Question 37

The portion of the x-ray machine that supplies the electrons to produce x-rays is the:

A)cathode.
B)anode.
C)control panel.
D)focusing cup.

Question 38

Which of the following is less sensitive to x-rays and therefore not considered a critical organ?

A)Skin
B)Muscle
C)Thyroid gland
D)Lens of the eye

Question 39

Primary radiation is:

A)also called the useful beam.
B)the beam of x-rays that comes from the target.
C)less penetrating than secondary radiation.
D)both a and b

Question 40

A step-down transformer is necessary within the x-ray circuitry to:

A)increase exposure time.
B)move electrons at a high speed to the target.
C)boil off electrons from the filament.
D)do all of the above.

Question 41

An exposure time of 1/2 second is equal to _____ impulse(s).

A)1/2
B)12
C)30
D)2

Question 42

A good technique for reducing the radiation exposure to both patient and operator is the use of:

A)a lead apron.
B)thinner films.
C)fast film or digital imaging.
D)an automatic processor.

Question 43

How well the image reproduces fine detail or distinct outlines of an object is called:

A)sharpness.
B)magnification.
C)density.
D)contrast.

Question 44

The dentist says that the image has too much contrast; he would like to see more gray values.What adjustment would you make?

A)Increase mA.
B)Increase kVp.
C)Decrease kVp.
D)Decrease mA.

Question 45

When the master switch is on:

A)x-rays are being produced.
B)the red emission light will illuminate.
C)the electron cloud is emitted.
D)all of the above.

Question 46

All the following are true statements about film badges except:

A)they should be worn at work only.
B)the badge is usually worn for 3 to 4 weeks before returning it for reading.
C)they should be worn when any form of x-ray is taken.
D)if an assistant follows all safety precautions; exposure should be near zero.

Question 47

The location where x-rays are produced in the x-ray tube is called the:

A)focal spot.
B)filament.
C)window.
D)PID.

Question 48

A radiograph that has an overall gray appearance is generally preferred.This radiograph is said to have:

A)high density.
B)low density.
C)high contrast.
D)low contrast.

Question 49

The maximum permissible dose for an occupational worker for an individual 18 years of age or older is _____ rem/year.

A)3
B)5
C)1.25
D)0.3

Question 50

When the electrons slam against the target,_______ are generated.

A)99% heat and 1% x-rays
B)1% heat and 99% x-rays
C)50% x-rays and 50% heat
D)only x-rays

Question 51

If a patient is small and petite,to get the same density radiograph it is best to reduce the:

A)exposure time.
B)mA.
C)kVp.
D)exposure time and mA.

Question 52

An example of cumulative radiation exposure is:

A)cataracts.
B)leukemia.
C)cancer.
D)all of the above.

Question 53

If the operator's film badge indicates an exposure to small amounts of radiation,what should be done?

A)Consult a physician.
B)Ignore the report.
C)Evaluate the x-ray equipment and techniques.
D)Change the mA and kVp.

Question 54

One of the earliest signs of overexposure to x-rays may be:

A)keratosis.
B)loss of hair.
C)erythema.
D)blindness.

Question 55

When in storage,the lead apron should be:

A)hung.
B)folded.
C)draped over a bar.
D)both a and c

Question 56

What happens when the exposure button is engaged?

A)The high-voltage circuit is activated.
B)Kilovolts drive the electrons to the target.
C)Electrons slam against the target producing the x-ray.
D)All of the above are correct.

Question 57

Who should hold the film in a patient's mouth if the patient is unable to do so?

A)Receptionist
B)Parent or relative of the patient
C)Assistant
D)Dentist

Question 58

A patient is concerned with radiation exposure.You can assure him that your office uses the ALARA concept,which includes:

A)reducing the number of exposures.
B)minimizing retakes.
C)keeping exposures levels as low as possible.
D)all of the above.