Test 1 Radiology 252

Question 1

Who discovered x-rays?

Answer 1

Wilhelm Conrad Roentgen in 1895

Question 2

Which of the following was Otto Walkhoff’s contribution to dental radiography?

Answer 2

He made the first dental radiograph.

Question 3

Who made the first dental radiograph using a skull?

Answer 3

W. J. Morton made the first dental radiograph in the United States using a skull.

Question 4

Who made the first dental radiograph on a living person?

Answer 4

C. Edmund Kells exposed the first dental radiograph in the United States using a living person.

Question 5

Which of the following was the most recent development in the history of dental x-ray equipment?

Answer 5

Introduction of a recessed long-beam tubehead in 1966.

Question 6

Who developed the first hot cathode x-ray tube?

Answer 6

The first hot-cathode x-ray tube was developed in 1913 by William D. Coolidge.

Question 7

Current, fast film requires less than __% of the initial exposure times used for dental radiography in 1920.

Answer 7

2 percent

Question 8

The long-cone paralleling technique was introduced by ______________ in 1947.

Answer 8

F. Gordon Fitzgerald

Question 9

Who introduced the paralleling technique?

Answer 9

The paralleling technique was first introduced by C. Edmund Kells in 1896.

Question 10

Which is true concerning atomic structure?

Answer 10

The strongest binding energy for electrons is found closest to the nucleus whereas electrons located in the outer shells have a weak binding energy. Protons carry positive electrical charges, whereas neutrons carry no electrical charge. Electrons are tiny, negatively charged particles that have very little mass; an electron weighs approximately 1/1800 as much as a proton or neutron. The K shell is located closest to the nucleus and has the strongest binding energy.

Question 11

Identify the term used to describe an atom that has lost an electron from its orbit:

Answer 11

An ion refers to an atom that has gained or lost an electron.
A photon is a bundle of energy with no mass or weight.
A neutron is a neutral or uncharged particle.
A particle is a minute part of matter.

Question 12

Identify which of the following processes occurs with ionization:

Answer 12

an electron is displaced from its orbit

Question 13

Identify which of the following is not a type of particulate radiation:

Answer 13

Nucleons are not a type of particulate radiation; a nucleon is a part of an atomic nucleus. Alpha particles, beta particles, and protons are all types of particulate radiation because they are accelerated particles.

Question 14

Identify which of the following is not a type of electromagnetic radiation:

Answer 14

Electrons are not a type of electromagnetic radiation. Radar waves, microwaves, and x-rays are an example of electromagnetic radiation; x-rays are present on the electromagnetic spectrum and possess wavelike energy that moves through space or matter without mass.

Question 15

Identify which of the following is not a property of x-rays:

Answer 15

the ability to fluoresce all materials. X-rays can cause certain substances to fluoresce. X-rays can penetrate organic matter. X-rays do produce ionization of matter. X-rays are able to produce latent images.

Question 16

Identify which of the following is false:

Answer 16

x-rays travel at the speed of sound. X-rays do not travel at the speed of sound. X-rays travel at the speed of light.
X-rays cause ionization.
X-rays cannot be focused to a point.
X-rays have no charge.

Question 17

Identify which of the following element(s) is/are located within the x-ray tube:

Answer 17

anode
cathode
focusing cup
The positively charged anode and the negatively charged cathode are inside the x-ray tube. The focusing cup is a part of the cathode.

Question 18

Identify the part of the x-ray tube that contains the focal spot:

Answer 18

The anode is the electrode that contains the focal spot.
The cathode contains the tungsten filament and focusing cup.
The filament is a part of the cathode electrode.
The focusing cup is a part of the cathode electrode.

Question 19

Identify the part of the x-ray tube where x-ray photons are produced:

Answer 19

X-rays are produced at the positively charged anode when the electrons are converted into x-ray photons.

Question 20

Which of the following is true of the conversion of the kinetic energy of the electrons into x-ray photons through general radiation?

Answer 20

General radiation consists of x-rays of many different energies and wavelengths.

Question 21

Identify the best description of primary radiation:

Answer 21

the beam that exits the tubehead. Primary radiation is defined as the beam that exits the tubehead. The beam created when x-rays contact matter is termed secondary radiation. The beam that is deflected from its path by interaction with matter is termed scatter radiation. Secondary and scatter radiation are less penetrating than primary radiation.

Question 22

Identify the term used to describe the x-ray beam that exits the PID:

Answer 22

Primary radiation is defined as the x-ray beam that exits the PID. The beam created when x-rays contact matter is termed secondary radiation. The beam that is deflected from its path by interaction with matter is termed scatter radiation. Direct radiation is not a term used in dental imaging.

Question 23

Identify the radiation produced when the primary beam interacts with matter:

Answer 23

Secondary radiation is produced when the primary beam interacts with matter. Leakage radiation is any radiation, except for the primary beam, that is emitted from the dental tubehead. Primary radiation is the beam that exits the tubehead. Diverging radiation is another term to describe radiation that is scattered.

Question 24

Identify the characteristics of x-rays produced with a high kilovoltage: 1. more penetrating 2. less penetrating 3. of longer wavelength 4. of shorter wavelength

Answer 24

1 and 4.When kilovoltage settings are increased, a higher energy x-ray beam is produced with a more penetrating beam; more penetrating x-rays with greater energy also demonstrate shorter wavelengths.

Question 25

Identify the function of the kilovoltage setting on the x-ray machine:

Answer 25

controls the penetrating power of the x-ray beam. The kilovoltage setting controls the penetrating power of the beam. The milliamperage and time settings control the quantity of x-rays produced. The number of photons available is controlled by the milliamperage and time settings.

Question 26

Which of the following is the term used to describe the overall blackness or darkness of a dental image?

Answer 26

Density is the overall blackness or darkness of an image. Contrast is defined as how sharply the dark and light area are differentiated or separated on an image. Overexposure refers to a darkened image resulting from incorrect time settings. Intensity refers to the total energy of the x-ray beam.

Question 27

Which of the following exposure factor(s) is used to modify contrast in dental imaging?

Answer 27

An adjustment in kilovoltage results in a change in the contrast of a dental image. When low kilovoltage settings are used, a high-contrast image will result. With high kilovoltage settings, low contrast results. Changes in milliamperage, exposure time, and processing time affect density but do not affect contrast.

Question 28

Which of the following choices correctly identifies the density and contrast of a dental image produced using a high kilovoltage setting?

Answer 28

increased density; low contrast. A high kilovoltage setting will produce an image of increased density (which can be described as a darker image), and “low” contrast (which can be described as many shades of gray).

Question 29

Identify the kilovoltage (kV) setting that produces the greatest contrast among images on a radiograph

Answer 29

"Greatest" contrast refers to an image that has high contrast, or many black and white areas; this type of image is produced with lower kilovoltage settings (65-70kV). Low contrast results with high kilovoltage settings (90 kV). An image with low contrast is useful for the detection of periodontal or periapical disease.

Question 30

Identify the unit of time used to measure x-ray exposure:

Answer 30

impulses. Exposure time is measured in impulses because x-rays are created in a series of bursts or pulses rather than a continuous stream. Ampere is the unit used to measure the number of electrons in an electrical current. Milliampere regulates the temperature which determines the number of electrons in the electrical current. Voltage is the unit used to measure the force needed to drive an electric current through a circuit.

Question 31

Identify the function(s) of the milliamperage setting on the x-ray machine:

Answer 31

The milliamperage controls both the quantity of x-rays produced and the temperature of the tungsten filament. The quality of the x-rays produced is controlled by the kilovoltage.

Question 32

Identify which of the following is determined by the milliamperage and exposure time settings:

Answer 32

Both milliamperage and exposure time settings determine the number of x-rays produced. Energy of the radiation produced is determined by the kilovoltage peak. Amount of film fog is not determined by exposure settings. The penetrating ability of the x-ray beam is determined by the kilovoltage peak.

Question 33

Identify which of the following results when a receptor is exposed with a high milliamperage setting:

Answer 33

A high milliamperage setting produces an image of increased overall density, or a darker image because more photons are being produced at the target.The contrast of the image is determined by the kilovoltage.

Question 34

Identify the intensity of the x-ray beam if the PID is increased from 8 inches to 16 inches:

Answer 34

Utilizing the inverse square law, the beam will be one quarter as intense.

Question 35

X-radiation causes cell damage primarily through formation of:

Answer 35

Free radical formation occurs when an x-ray photon ionizes water, the primary component of living cells. Ionization of water results in the production of hydrogen and hydroxyl free radicals. X-radiation can directly strike the DNA of a cell and cause injury to the irradiated organism. Direct injuries from exposure to ionizing radiation occur infrequently; most x-ray photons pass through the cell and cause little or no damage.

Question 36

Identify the portion of the cell that is damaged when a genetic mutation results:

Answer 36

DNA

Question 37

Which of the following is true of nonstochastic effects of radiation?

Answer 37

Effects have a threshold. Nonstochastic effects are somatic effects that have a threshold and increase in severity with increasing absorbed dose. Compared with stochastic effects, nonstochastic effects require larger radiation doses to cause serious impairment of health. Stochastic effects occur as a direct function of dose. The severity of stochastic effects does not depend on the magnitude of the absorbed dose. The probability of occurrence increases with increasing absorbed dose for stochastic effects of radiation.

Question 38

Identify which of the following is true concerning radiation injury:

Answer 38

Cumulative effects of repeated radiation exposure can lead to health problems such as cancers, cataracts, or birth defects. Some radiation injuries are evident immediately; others may take years to become apparent. X-radiation can injure somatic and genetic cells. Acute injury caused by x-radiation is uncommon.

Question 39

Which of the following types of cells are most sensitive to radiation? 1. Rapidly dividing cells. 2. Slowly dividing cells. 3. Cells of children rather than adults. 4. Cells of adults rather than children.

Answer 39

1 and 3

Question 40

Identify the radiation effects that occur in the exposed person, not in the reproductive cells:

Answer 40

Somatic effects are seen in the person irradiated. Genetic effects are not seen in the person irradiated but are passed on to future generations. Short-term effects are seen within minutes, days, or weeks of exposure.

Question 41

Identify the most dangerous time for a fetus to be exposed to ionizing radiation:

Answer 41

The most dangerous time for a fetus to be exposed to ionizing radiation is during the first trimester because the fetal cells have high mitotic activity and cell differentiation, making them highly sensitive to radiation.

Question 42

Identify why a child's cells are more susceptible to damage from x-radiation than adult cells:

Answer 42

Because a child is younger than an adult, their more rapid cell reproduction renders their cells more susceptible to radiation damage.

Question 43

Which of the following is the most radiosensitive tissue or organ?

Answer 43

Radiosensitive organs are composed of radiosensitive cells and include lymphoid tissues, bone marrow, testes, and intestines. The salivary glands, kidneys, and the liver are an example of radioresistant organs.

Question 44

Identify the cells that are most sensitive to x-radiation:

Answer 44

Of the choices listed, small lymphocytes are the most sensitive to x-radiation. Nerve cells and, muscle cells are radioresistant.

Question 45

Which of the following is the SI system equivalent of the radiation absorbed dose (rad)?

Answer 45

The gray (Gy) is the SI system equivalent of the radiation absorbed dose (rad). The conversions for rad and Gy can be expressed as: 1 rad = 0.01 Gy or 1 Gy = 100 rads. The sievert (Sv) is the SI unit equivalent of the rem. Exposure in the SI system is measured in coulombs per kilogram (C/kg). The unit C/kg measures the number of electrical charges, or the number of ion pairs, in 1 kg of air. There is not SI unit for exposure that is the equivalent of the roentgen. The SI unit equivalent of the rem is the sievert (Sv). Conversions for the rem and sievert can be expressed as: 1 rem = 0.01 Sv or 1 Sv = 100 rems.

Question 46

The potential risk of dental imaging inducing a fatal cancer in an individual has been estimated to be approximately ___ in 1 million.

Answer 46

3. The risk of a person developing cancer spontaneously is much higher, or 3300 in 1 million. Risk estimates suggest that death is more likely to occur from common activities than from dental radiographic procedures and that cancer is much more likely to be unrelated to radiation exposure

Question 47

Identify the x-rays that are most likely absorbed by the skin, thus causing x-ray injury:

Answer 47

Long-wavelength x-rays are lower in energy, are more likely to be absorbed by the skin, and are harmful to the patient. They are not useful in diagnostic dental imaging. Deep, penetrating x-rays, x-rays that are filtered by aluminum, and short-wavelength x-rays are not likely to be absorbed in the skin.

Question 48

Identify an early clinical sign of excessive exposure to radiation:

Answer 48

erythema

Question 49

Identify the reduction in absorbed dose when changing from D-speed film to F-speed film:

Answer 49

60 percent

Question 50

Which of the following combinations of film speed and collimation for dental imaging will result in the lowest dose to the patient?

Answer 50

F-speed film with rectangular collimation

Question 51

Identify which of the following is most effective in reducing x-radiation exposure:

Answer 51

The 16-inch PID is more effective in reducing radiation exposure than an 8-inch PID because of less divergence of the x-ray beam. Rectangular collimation reduces x-radiation exposure more effectively than circular collimation.

Question 52

Which of the following statements is/are true concerning prescribing dental radiographs?

Answer 52

Every patient’s dental condition is different. The dentist uses professional judgment to make decisions about the number, type, and frequency of dental radiographs. A radiographic examination should never include a predetermined number of radiographs, nor should radiographs be taken at predetermined time intervals.

Question 53

Identify which of the following is not a component of inherent filtration:

Answer 53

The lead-lined cone is not a component of inherent filtration. Inherent filtration takes place when the primary beam passes through the insulating oil, the unleaded glass window, and the tubehead seal.

Question 54

Identify which of the following is used to make a filter:

Answer 54

Aluminum is used to make the filter. Copper is used on the anode. Lead is used to make the collimator. Tungsten is used in the anode and cathode.

Question 55

The purpose of the aluminum disks is to filter out:

Answer 55

The aluminum disks will filter out longer wavelength, low-energy x-rays that are not useful in diagnostic dental imaging. These x-rays do not have enough energy to reach the image receptor.

Question 56

Identify the function of filtration:

Answer 56

The function of the filter is to remove the long wavelengths, which are also lower-energy x-rays, from the beam. The collimator is used to restrict the size and shape of the x-ray beam.

Question 57

Which of the following statements is true regarding the types of filtration used in the dental x-ray tubehead?

Answer 57

Machines operating above 70 kV require a minimum total of 2.5 mm aluminum filtration.

Question 58

Identify the function of the collimator:

Answer 58

The function of the collimator is to restrict the size and shape of the x-ray beam. The function of the filter is to remove the long wavelengths from the x-ray beam and remove the low-energy x-rays from the beam. The collimator does not increase scatter radiation.

Question 59

Identify which of the following is used to make a collimator:

Answer 59

The collimator is made of lead. The filter is made of aluminum is used to make the filter. Copper is used on the anode. Tungsten is used in the anode and the cathode.

Question 60

A rectangular collimator:

Answer 60

A rectangular collimator restricts the size of the x-ray beam to an area slightly larger than a size 2 intraoral receptor. A circular collimator produces a cone-shaped beam that is 2.75 inches in diameter, which is considerably larger than a size 2 intraoral receptor and exposes the patient to more radiation than a rectangular collimator. Filtration filters out the longer wavelength, low-energy x-rays from the x-ray beam.

Question 61

Identify the maximum diameter of the collimated x-ray beam as it exits the PID:

Answer 61

Federal regulations require that the x-ray beam be collimated to a diameter of no more than 2.75 inches as it reaches the skin of the patient.

Question 62

Identify the potential sources of occupational exposure to x-radiation:

Answer 62

Primary, leakage, and scattered radiations are all potential sources of occupational exposure to x-radiation.

Question 63

Identify the recommended distance from the radiographer to the tubehead during x-ray exposure:

Answer 63

to maintain adequate distance during exposure, the dental radiographer must stand at least 6 feet away from the x-ray tubehead.

Question 64

Identify the recommended positioning of the dental radiographer to the primary beam:

Answer 64

The recommended operator position for avoiding the primary beam is to stand at a 90- to 135-degree angle to the beam; the operator avoids the primary beam, which travels in a straight line, by standing perpendicular to the beam, or at 90 degrees.

Question 65

Where should a film badge be worn?

Answer 65

At waist level

Question 66

Identify the maximum permissible dose (MPD) of an occupationally exposed person:

Answer 66

0.05 Sv/year (5.0 rem/year)

Question 67

Identify the maximum permissible dose (MPD) of a nonoccupationally exposed person:

Answer 67

0.005 Sv/year (0.5 rem/year)

Question 68

The “R” of ALARA stands for:

Answer 68

reasonably. The ALARA concept states that all exposure to radiation must be kept to a minimum, or “as low as reasonably achievable.”

Question 69

The exposure light turns ________ and the beep ______ when the x-ray exposure is completed.

Answer 69

off; stops. As a visible sign that x-rays are being produced, an exposure light on the control panel is illuminated during x-ray exposure. In addition, a beep sounds during x-ray exposure as an audible signal that x-rays are being produced. The exposure light turns off and the beep stops when the x-ray exposure is completed.

Question 70

Beam alignment devices and collimating devices are used to indicate the position of the _______ in relation to the tooth and the receptor?

Answer 70

position-indicating device (PID)

Question 71

Which of the following is true regarding intraoral periapical dental images?

Answer 71

It is used to examine the entire tooth and supporting bone. The term periapical is derived from the Greek word peri, meaning “around”, and the Latin word apex, referring to the terminal end of a tooth root. This type of dental image shows the tip of the tooth root and surrounding structures as well as the crown. The bite-wing image is used to examine the crowns of both maxillary and mandibular teeth on one dental image. The patient “occludes”, or bites on the entire receptor for an occlusal image. The occlusal receptor is larger than periapical or bite-wing receptors.

Question 72

Identify the periapical receptor size used for a maxillary premolar exposure in an adult patient:

Answer 72

Size 2 images examine the anterior and posterior teeth in adults. Size 1 images are used for bite-wings for children and anterior teeth in adults. Size 3 images are used only for bite-wing examination. Size 4 images are used for occlusal projections.

Question 73

Identify the characteristic(s) of a dental x-ray image that (is/are) associated with the term radiolucent?

Answer 73

Radiolucent refers to that portion of a processed dental image that is dark or black. Radiopaque refers to that portion of a processed radiograph that appears light or white. Radiopaque structures are dense and absorb or resist the passage of the x-ray beam.

Question 74

All of the following would appear radiolucent on a radiograph except:

Answer 74

Bone is radiopaque on a radiograph; bone is dense and absorbs the radiation, producing a white or radiopaque area on the resultant image. Dental pulp, air space, and dental caries are radiolucent on a radiograph.

Question 75

All of the following would appear radiopaque on a radiograph except:

Answer 75

Periodontal ligament space is radiolucent on a radiograph; the PDL lacks density and permits the passage of the x-ray beam with little or no resistance. Amalgam, enamel, and dentin are radiopaque on a radiograph.

Question 76

Which of the following areas would appear gray on a radiographic image of correct density?

Answer 76

Soft tissue will appear gray on an image of correct density. Dentin will appear white on an image of correct density. Air spaces will appear black on an image of correct density. Bone will appear white on an image of correct density.

Question 77

Which of the following choices will create an image of decreased density?

Answer 77

An increase in the amount of soft tissue or thick, dense bone will result in an image that has less density and appears lighter. Adjustments in operating kilovoltage, milliamperage, or exposure time can be made to compensate for variations in the size of patients and subject thickness. An increase in milliamperage (mA) produces more x-rays that expose the receptor and increases density. An increase in operating kilovoltage (kV) increases density by increasing the mean or average energy of the x-rays and by producing x-rays of higher energy. An increase in exposure time increases density by increasing the total number of x-rays that reach the receptor surface.

Question 78

Identify the exposure factor adjustment used to produce a beam with greater penetrating power:

Answer 78

Increasing the kilovoltage creates a more penetrating beam with higher quality. The milliamperage affects the amount of x-rays produced. The time setting affects the amount of x-rays produced. Increasing the target-receptor distance produces a beam with lower penetrating power.

Question 79

The primary benefit of dental imaging is:

Answer 79

Although dental images have many uses, the primary use is detection of diseases, lesions, and conditions of the teeth and bones. Dental images can also be used to examine the status of the teeth and bone during growth and development. Dental images are obtained to benefit the patient. Dental imaging is useful in assisting in the localization of lesions and foreign objects, but it is not considered to be the primary benefit.

Question 80

Because media reports often cause the patient to fear the use of x-radiation and to avoid all radiation exposure, the dental radiographer must be prepared to explain why dental imaging is important, how dental images are used, and how:

Answer 80

they benefit the patient. The dental radiographer must be prepared to explain how dental imaging benefits the patient. In addition, the dental professional must be able to discuss common conditions and lesions that can be detected only through the use of dental radiographs. No amount of radiation is considered safe. All x-rays are harmful to living tissue. The level of care received by the patient should not be dictated by the level of insurance benefit. No set time interval exists between x-ray examinations. Decisions about the number, type, and frequency of dental x-rays are determined by the dentist based on individual needs.

Question 81

Which of the following is a semicritical instrument that may be utilized during dental imaging procedures?

Answer 81

Instruments that contact but do not penetrate soft tissue or bone are classified as semicritical. Beam alignment devices are an example of a semicritical instrument. b. The position-indicating device of the dental x-ray tubehead, c. the x-ray control panel, and d. the lead apron are examples of noncritical instruments.

Question 82

After each patient has been treated, _________________ (is/are) recommended for all surfaces that have been contaminated.

Answer 82

intermediate-level disinfectants

Question 83

______________ should be used to prevent cross-contamination when using digital sensors.

Answer 83

Sensors used in indirect digital imaging must be wrapped in plastic barrier envelopes and direct digital imaging sensors require plastic disposable sleeves to prevent cross-contamination. Also, the CDC recommends cleaning and disinfecting the sensor with an EPA-registered intermediate level disinfectant after removing the barrier and before use on another patient.

Question 84

Which of the following is true regarding infection control procedures for the dental radiographer and patient prior to the dental imaging procedure?

Answer 84

The use of a surgical mask and protective eyewear by the dental radiographer is optional.

Question 85

The bite-wing imaging receptor is used in the ____________ examination.

Answer 85

interproximal. The bite-wing receptor is used in the interproximal examination. The interproximal examination is used to examine the crowns of both the maxillary and mandibular teeth on a single image. The periapical examination is used to examine the entire tooth and supporting bone. The periapical receptor is used in the periapical examination. The occlusal examination is used to examine large areas of the maxilla or the mandible on one image. The occlusal receptor is used in the occlusal examination.

Question 86

How many periapical images are usually sufficient to cover the edentulous arches in the patient without teeth?

Answer 86

In the patient without teeth, fourteen periapical images are usually sufficient to cover the edentulous arches. Four bitewing images are usually exposed for a dentulous patient. To include every tooth and tooth-bearing areas on a dentulous patient, a range of 14-20 images may be included in the CMRS.

Question 87

Identify the positioning of the image receptor in relation to the tooth when using the paralleling technique:

Answer 87

To utilize the paralleling technique correctly, place the image receptor parallel to the long axis of the tooth and direct the x-ray beam perpendicular to the tooth and the image receptor. This will minimize dimentional distortion. Placing the image receptor in direct contact with the tooth is characteristic of the bisecting technique. Placing the image receptor on the occlusal surface of the tooth is characteristic of the occlusal techniqu

Question 88

Identify the benefit of using a long-cone (16") position-indicating device (PID) versus a short-cone (8") PID:

Answer 88

When a longer PID is used, more parallel rays strike the object, which results in less image magnification. The length of the PID does not affect the distortion, definition, or the resolution of the image.