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

Question 1

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

A)John Greenwood.
B)Wilhelm Conrad Roentgen.
C)CHOICE BLANK
D)Edmund Kells.
E)V. Black.

Answer 1

Wilhelm Conrad Roentgen.

Question 2

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.

Answer 2

The orbital path of an electron around the nucleus is called an electron shell.

Question 3

Which of the following structures will appear radiopaque on dental x-ray film?

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

Answer 3

Metal restorations

Question 4

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 5

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

A)Wilhelm Conrad Roentgen.
B)CHOICE BLANK
C)Edmund Kells.
D)John Greenwood.
E) V. Black. c.

Question 6

Damage caused by ionizing x-radiation to genetic cells:

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

Question 7

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 8

Which of the following tissues has the highest radiation sensitivity?

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

Question 9

One of the rules of radiation protection is to 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

Question 10

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 on 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 11

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 12

A lead apron and a thyroid collar:

A)are utilized 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 13

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 14

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

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

Question 15

_____ will improve the sharpness of a radiographic image.

A)A larger focal spot size
B)Faster film
C)Smaller film crystal size
D)Movement of the patient

Question 16

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

Question 17

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 18

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

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

Question 19

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

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

Question 20

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 21

Which of the following organs are not more sensitive to x-rays and therefore not considered critical organs?

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

Question 22

The _______is the portion of the x-ray machine which supplies the electrons to produce x-rays?

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

Question 23

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 24

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 25

Filtration is used to _____ and are discs 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 26

Which council determines the radiation effects and levels tolerable for humans?

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 these groups make recommendations.

Question 27

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 28

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 29

Which is not true of electromagnetic radiation?

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

Question 30

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)all of the above.

Question 31

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

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

Question 32

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 33

The lead collimator is used to ______ of the primary beam.

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

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)all of the above.

Question 35

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

A)Somatic cell
B)Genetic cell
C)Damage to either somatic cells or genetic cells is passed on to future generations
D)Damage to neither somatic cells nor genetic cells is passed on to future generations

Question 36

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 37

The _____ setting controls the penetrating power of the x-ray beam.

A)impulse timer
B)kilovolt setting
C)milliamp setting
D)all of the above

Question 38

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 39

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

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

Question 40

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 41

Which of the following is an example of cumulative radiation exposure?

A)Cataracts
B)Leukemia
C)Cancer
D)All of the above

Question 42

An exposure time of ½ second is equal to _____ impulses.

A)½
B)12
C)30
D)2

Question 43

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 44

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 45

When in storage,the lead apron should be:

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

Question 46

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

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

Question 47

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

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

Question 48

When the exposure button is engaged,what happens?

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 happen.

Question 49

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 50

A patient is concerned with radiation exposure.You can assure him that your office utilizes the ALARA concept.What does that include?

A)Reducing the number of exposures
B)Minimizing retakes
C)Keeping exposures levels as low as possible
D)All of the above

Question 51

The maximum permissible dose for an occupational worker for an individual 18 years old or over is ___ rems per year:

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

Question 52

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)both a and b.

Question 53

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 54

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

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

Question 55

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 56

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 57

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

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

Question 58

Which is not true regarding film badges?

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.