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DANB RHS Exam (new) > Chapters 3-4: Radiation Biology & Radiation Protection > Flashcards

Chapters 3-4: Radiation Biology & Radiation Protection Flashcards

1
Q

Define the term: radiation biology

A

the study of the effects of ionizing radiation on living tissues

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2
Q

Define the term: absorption

A

the total transfer of energy from the x-ray photon to the atoms of matter through which the x-ray beam passes

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3
Q

Define the term: ionizing radiation

A

radiation capable of producing ions

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4
Q

Define the term: ionization

A

the process of converting an atom into an ion, resulting in the formation of a positive atom and a dislodged negative electron

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5
Q

Define the term: exposure

A

a measure of ionization produced in the air by x-radiation or gamma radiation

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6
Q

Define the term: collimation

A

the restriction of the size and shape of the x-ray beam in order to reduce patient exposure

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7
Q

Define the term: image receptor

A

a recording medium (ex: PSP plates or digital sensors)

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8
Q

Define the term: imaging technique

A

the style and process of exposing image receptors (ex: paralleling, bisecting, panoramic)

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9
Q

Define the term: primary beam

A

the penetrating x-ray beam produced at the target of the anode and exits the x-ray tubehead

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10
Q

Define the term: scatter radiation

A

a form of secondary radiation that results from an x-ray beam that has been deflected from its path by the interaction with matter

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11
Q

What are considered exposure factors?

A

factors that influence the diagnostic quality of an image (ex: kilovoltage, milliamperage, exposure time settings)

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12
Q

Define the term: diagnostic image

A

a dental image that allows for the identifying and monitoring of diseases or injuries

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13
Q

Define the term: non-diagnostic image

A

an image that has undergone exposure or technique errors that cannot be used in the proper diagnosis of disease or injuries, and must be retaken

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14
Q

List the two mechanisms of radiation injury.

A
  1. ionization
  2. free radical formation
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15
Q

Explain the ionization mechanism of radiation injury.

A
  1. x-rays are a form of ionizing radiation that interact with and are absorbed by tissues
  2. the kinetic energy caused during absorption can cause further ionization
  3. these chemical changes can result in biologic damage to cells
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16
Q

Define the term: free radical

A

an uncharged, neutral atom or molecule that exists with a dingle, unpaired electron in its outermost shell

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17
Q

What is the primary mechanism of radiation injury in dental imaging?

A

free radical formation

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18
Q

List the two theories of radiation injury.

A
  1. direct theory
  2. indirect theory
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19
Q

What is the direct theory of radiation injury?

A

cell damage results when ionizing radiation directly hits critical areas within th ecell

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20
Q

What is the indirect theory of radiation injury?

A

x-ray photons are absorbed within the cell and cause the formation of toxins, which in turn damage the cell

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21
Q

Which theory of radiation injury is the least likely to occur in dental imaging?

A

direct theory

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22
Q

Define the term: radiation injury

A

biologic effects on tissues as a result of the exposure to radiation

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23
Q

True or false: All ionizing radiations are harmful and produce biologic damage.

A

True

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24
Q

What is the purpose of a dose-response curve?

A

to correlate the response or damage of tissues with the dose or amount of radiation recieved

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25
Q

List the two types of radiation effects on human tissue.

A
  1. stochastic effects
  2. nonstochastic effects
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26
Q

What are stochastic effects of radiation?

A
  • biologic effects of radiation that occur as a direct function of dose
  • the probability of occurence increases with increasing absorbed dose; however, the severity of effects does not depend on the magnitude of absorbed dose
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27
Q

What are nonstochastic effects of radiation?

A

effects of radiation that have a threshold and increase in severity with increasing absorbed dose

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28
Q

Leukemia and other types of cancers are examples of which type of radiation effect?

A

stochastic effects

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29
Q

Cataract formation, decreased fertility and radiation sickness are all examples of whihc type of radiation effect?

A

nonstochastic effects

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30
Q

After exposure, what are the next steps in radiation injury?

A
  1. latent period
  2. period of injury
  3. recovery period
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31
Q

What is the latent period in radiation injury?

A

the time that elapses between exposure to ionizing radiation and the appearance of observable clinical signs

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32
Q

What determines the length of the latent period in radiation injury?

A

the total dose of radiation or the rate/total time of radiation

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33
Q

What is the period of injury in radiation injury?

A

the sequence of radiation injury that occurs after the latent period following exposure to radiation that can include a variety of cellular injuries

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34
Q

What is the recovery period of radiation injury?

A

the sequence of radiation injury during which cellular damage caused by radiation begins to repair

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35
Q

Define the term: cumulative effects of radiation

A

the additive effects of repeated radiation exposure

36
Q

List the five factors that can influence the effects of radiation injury.

A
  1. total dose
  2. dose rate
  3. amount of tissue irradiated
  4. cell sensitivity
  5. age
37
Q

Define the term: total dose

A

the quantity of radiation received, or the total amount of radiation energy absorbed

38
Q

Define the term: dose rate

A

the rate at which exposure to radiation occurs and absorption takes place (dose rate = dose/time)

39
Q

What are short-term effects of radiation?

A
  • effects that are seen within minutes, days or weeks
  • associated with larger amounts of radiation absorbed in a short period of time
40
Q

Exposure to a nucleur accident or atomic bomb would induce what type of radiation effects?

A

short-term effects

41
Q

What is acute radiation syndrome (ARS)?

A

a short term effect of radiation that includes nausea, vomiting, diarrhea, hair loss, and hemorrhage

42
Q

Which type of radiation effect is not applicable in dentistry?

A

short-term effects

42
Q

What are long-term effects of radiation?

A
  • effects that appear years, decades, or generations after exposure
  • associated with small amounts of radiation absorbed repeatedly over a long period of time
43
Q

Birth abnormalities and genetic defects are examples of which type of radiation effect?

A

long-term effects

44
Q

Define the term: somatic cells

A

all cells in the body, with the exception of reproductive cells

45
Q

Define the term: somatic effects

A

radiation injuries that produce changes in somatic cells and produce poor health in the irradiated individual

46
Q

Define the term: genetic cells

A

cells that contain genes; reproductive cells

47
Q

Define the term: genetic effects

A

effects of radiation that are not seen in the person irradiated but are passed on to future generations through genetic cells

48
Q

Define the term: cell

A

the basic structural unit of living organisms

49
Q

Define the term: radiosensitive cell

A

a cell that is sensitive to radiation

50
Q

Define the term: radioresistant cell

A

a cell that is resistant to radiation

51
Q

How is the response of a cell to radiation exposure determined?

A
  • mitotic activity
  • cell differentiation
  • cell metabolism
52
Q

Define the term: mitotic activity

A

the process of cell division that determines the response of a cell to radiation exposure

53
Q

Define the term: cell differentiation

A

the individual characteristics of a cell that determine the response of a cell to radiation exposure

54
Q

Define the term: cell metabolism

A

the physical and chemical processes of a cell that determine the response of the cell to radiation exposure

55
Q

What cells are considered radiosensitive?

A

blood cells, immature reproductive cells, young bone cells, and the small lymphoctye

56
Q

What cells are considered radioresistant?

A

bone, muscle, and nerve cells

57
Q

Define the term: critical organ

A

an organ that, if damaged, diminishes the quality of an individual’s life

58
Q

What are considered critical organs in dental imaging?

A
  • thyroid gland
  • bone marroe
  • skin
  • lens of the eye
59
Q

What are the three quantiites of measurement in radiation?

A
  1. exposure
  2. dose
  3. dose equivalent
60
Q

What is the name of the current system of radiation measurement?

A

International System of Units (SI System)

61
Q

Define the term: coulomb (C)

A
  • a unit of electrical charge
  • the quantity of electrical charge transferred by 1 ampere in 1 second
62
Q

Define the term: dose

A

the amount of energy absorbed by a tissue

63
Q

Define the term: gray (Gy)

A

a unit for measuring absorbed dose

64
Q

Define the term: dose equivalent

A

a measurement used to compare the biologic effects of different types of radiation

65
Q

What is quality factor (QF)?

A

a factor used for radiation protection purposes that accounts for the exposure effects of different types of radiation

66
Q

Define the term: sievert (Sv)

A

a unit of measurement for dose equivalent

67
Q

What is background radiation?

A

a form of ionizing radiation that is ubiquitous in the environment

68
Q

List examples of background radiation.

A
  • radon in the air
  • cosmic rays from outer space and the sun
  • radioactive potassium in food and water
  • radioactive material in the human body
69
Q

What is the greatest source of background radiation in the United States?

A

radon gas in the soil

70
Q

What is artificial/human-made radiation?

A

radiation caused by modern technology

71
Q

What is medical radiation?

A

radiation exposure for medical diagnosis and treament

72
Q

Define the term: risk

A

the likelihood of adverse effects or death resulting from exposure to a hazard

73
Q

How can your choice of image receptor affect the patient’s exposure and dose?

A

using digital sensors can reduce the exposure time by 50-90% compared to conventional radiography

74
Q

How can collimation affect the patient’s exposure and dose?

A

exposure can be reduced by 60-70% when using a rectangular collimator instead of a round collimator

75
Q

How can your imaging technique affect the patient’s exposure and dose?

A

using the paralleling technique and increasing the target-receptor distance reduces the dose

76
Q

If leaving the room during exposure is not possible, how must the dental radiographer stand in relation to the primary beam?

A

at least 6 feet away from the x-ray tubehead, at a perpendicular angle to the primary beam

77
Q

True or false: A dental radiographer can hold an image receptor in place for a patient during exposure, if absolutely necessary.

A

False

78
Q

True or false: A dental radiographer can hold and stabilize the x-ray tubehead in place during exposure, if absolutely necessary.

A

False

79
Q

What is the benefit of a protective barrier to the dental radiographer?

A

standing behind a protective barrier during exposure will protect them from the primary beam and scatter radiation, thus reducing their occupational exposure

80
Q

What is the most common example of a protective barrier in a dental office?

A

a wall

81
Q

Define the term: leakage radiation

A

any radiation, with the exception of the primary beam, that is emitted from the x-ray tubehead

82
Q

What device can be implemented into daily use for the dental radiographer to measure the amount of occupational dose.

A

a radiation monitoring badge

83
Q

Define the term: maximum permissible dose (MPD)

A

the maximum dose equivalent that a body is permitted to receive within a specific period of time

84
Q

Define the term: cumulative occupational dose

A

the accumulated occupational dose for occupationally-exposed workers

85
Q

What is the ALARA concept?

A

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

DANB RHS Exam (new) (16 decks)

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