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Radiology > Lecture 2 > Flashcards

Lecture 2 Flashcards

1
Q

What is an X-ray?

A

A beam of energy that has the power to penetrate substances and record image shadows on receptors (photographic film or digital sensors).

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2
Q

What is radiation?

A

A form of energy carried by waves or a stream of particles.

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3
Q

What is radiology?

A

The study of images produced on a receptor by exposure to ionizing radiation.

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4
Q

What is a radiograph?

A

An image or picture produced on a receptor (radiation-sensitive film, phosphor plate, or digital sensor) by exposure to ionizing radiation; a two-dimensional representation of a three-dimensional object.

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5
Q

Who is a dental radiographer?

A

Any person who positions, exposes, and processes dental x-ray image receptors.

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6
Q

What is an image?

A

A picture or likeness of an object.

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7
Q

What is an image receptor?

A

A recording medium; examples include x-ray film, phosphor plate, or digital sensor.

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8
Q

Uses of dental radiograph

A

• To detect lesions, diseases, and conditions of the teeth and surrounding structures that cannot be identified clinically
• To confirm or classify suspected disease
• To localize lesions or foreign objects
• To provide information during dental procedures (e.g., root canal therapy, placement of dental implants)
• To evaluate growth and development
• To illustrate changes secondary to caries, periodontal disease, and trauma
• To document the condition of a patient at a specific point in time
• To aid in development of a clinical treatment plan

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9
Q

Who discovered x-rays?

A

Roentgen discovered x-rays in 1895.

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10
Q

Who made the first dental radiograph?

A

Otto Walkhoff made the first dental radiograph.

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11
Q

Who was the first to practically use radiographs?

A

C. Edmund Kells was the first to practically use radiographs in 1896.

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12
Q

What health issues did C. Edmund Kells face due to x-ray exposure?

A

C. Edmund Kells exposed his hands to numerous x-rays every day for years, developing numerous cancers in his hands and ultimately losing his fingers, hands, and then his arms.

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13
Q

What is the charge of most atoms?

A

Most atoms are neutral.

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14
Q

What does a neutral atom contain?

A

A neutral atom contains an equal number of protons and electrons.

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15
Q

What are the charges of protons and electrons?

A

Protons have positive charges and electrons have negative charges.

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16
Q

What is an ion?

A

An atom that gains or loses an electron and becomes electrically unbalanced is known as an ion.

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17
Q

What is ionization?

A

Ionization is the production of ions, or the process of converting an atom into ions.

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18
Q

The loss and gain of which molecule in an atom leads to ionization?

A

Ionization deals only with electrons and requires sufficient energy to overcome the electrostatic force that binds the electron to the nucleus.

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19
Q

What happens when an electron is removed from an atom during ionization?

A

When an electron is removed from an atom in the ionization process, an ion pair results.

The atom becomes the positive ion, and the ejected electron becomes the negative ion.

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20
Q

What occurs after an ion pair is formed?

A

This ion pair reacts with other ions until electrically stable, neutral atoms are formed.

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21
Q

Ionizing radiation can be defined as

A

radiation that is capable of producing ions by removing or adding an electron to an atom.

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22
Q

Long wavelength=

A

Low frequency

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23
Q

Short wavelength=

A

High frequency

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24
Q

What is the appearance of X-rays?

A

X-rays are invisible.

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25
Q

Do X-rays have mass?

A

X-rays have no mass or weight.

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26
Q

What is the charge of X-rays?

A

X-rays have no charge.

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27
Q

At what speed do X-rays travel?

A

X-rays travel at the speed of light.

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28
Q

What is the wavelength of X-rays?

A

X-rays travel in waves and have short wavelengths with a high frequency.

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29
Q

How do X-rays travel?

A

X-rays travel in straight lines and can be deflected, or scattered.

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30
Q

Can X-rays be focused?

A

X-rays cannot be focused to a point and always diverge from a point.

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31
Q

What is the penetrating power of X-rays?

A

X-rays can penetrate liquids, solids, and gases.

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32
Q

What determines the absorption of X-rays?

A

The absorption depends on the atomic structure of matter and the wavelength of the x-ray.

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33
Q

What is the ionization capability of X-rays?

A

X-rays interact with materials they penetrate and cause ionization.

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34
Q

Can X-rays cause fluorescence?

A

X-rays can cause certain substances to fluoresce or emit radiation in longer wavelengths.

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35
Q

What effect do X-rays have on receptors?

A

X-rays can produce an image on a receptor.

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36
Q

What effect do X-rays have on living tissues?

A

X-rays cause biologic changes in living cells.

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37
Q

What are the component parts of a dental X-ray machine?

A

• (1) control panel
• (2) extension arm
• (3) tubehead

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38
Q

List all parts

A

A. X-ray tube
B. Anode [+]
C. Unleaded glass window of X-ray tube
D. Insulating oil
E. Metal housing of X-ray tubehead
F. Position indicating device
G. Aluminum disks
H. Lead collimator
I. Cathode [-]
J. Filament circuit
K. Tubehead seal

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39
Q

What is this?

A

X-ray Tube

40
Q

What does the x-ray tube produce?

A

The x-ray tube produces x-rays.

41
Q

What is a x-ray tube?

A

The x-ray tube is a glass vacuum tube from which all the air has been removed.

42
Q

What is the purpose of the copper stem?

A

The purpose of the copper stem is to dissipate heat and conduct it away.

43
Q

A transformer is a device that is used to

A

either increase or decrease the voltage in an electrical circuit

44
Q
A
  1. Focal spot on tungsten target
  2. Glass envelope
  3. Vacuum
  4. Copper stem
  5. Anode (+)
  6. Useful X-ray beam
  7. Tube window
  8. Cathode (-)
  9. Electronic focusing cap
  10. Filament electron cloud
45
Q

What is shown in this picture?

A

The production of X-rays in the X-ray tube

46
Q

What is primary radiation?

A

Primary radiation refers to the penetrating x-ray beam that is produced at the target of the anode and that exits the tubehead.

47
Q

What is secondary radiation?

A

Secondary radiation refers to x-radiation that is created when the primary beam interacts with matter. Secondary radiation is less penetrating than primary radiation.

48
Q

What is scatter radiation?

A

Scatter radiation is a form of secondary radiation and is the result of an x-ray that has been deflected from its path by the interaction with matter.

49
Q

Scatter radiation is deflected_____

A

in all directions by the patient’s tissues and travels to all parts of the patient’s body and to all areas of the dental operatory.

50
Q

Scatter radiation is detrimental to____

A

both the patient and the radiographer.

51
Q

What are the different way an X-ray can interact after being exposed to the patient?

A

• X-rays can pass through the patient without any interaction.
• X-ray photons can be completely absorbed by the patient.
• X-ray photons can be scattered

52
Q

What is the effect of all ionizing radiation on living tissue?

A

All ionizing radiation is harmful and produces biologic changes in living tissue.

53
Q

What causes radiation injury?

A

Radiation injury results from ionization or free radical formation.

54
Q

What are the phases of radiation injury?

A

Radiation injury follows a sequence of events: latent period, period of injury, and period of recovery.

55
Q

What factors affect radiation injury?

A

Radiation injury is affected by total dose, dose rate, amount of tissue irradiated, cell sensitivity, and patient’s age.

56
Q

How may Xrays lead to biological changes?

A
57
Q

What is the mechanism of direct radiation injury?

A

X-ray photons directly strike the DNA of a cell.

58
Q

What is the mechanism of indirect radiation injury?

A

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

E.g. H2O2 formed from free radicals.

59
Q

What are the two mechanisms for radiation injury?

A

Direct and indirect

60
Q

A dose-response curve is

A

used to demonstrate the response (damage) of tissues to the dose (amount) of radiation received.

61
Q

A threshold dose for damage does not exist, and the response of tissues is_____ to the dose received.

A

directly proportional

62
Q

All the cells in the body can be classified as either

A

somatic or genetic.

63
Q

Somatic cells are

A

all the cells in the body except the reproductive cells.

64
Q

The reproductive cells are

A

termed genetic cells. (e.g., ova, sperm)

65
Q

What is this picture demonstrate?

A

That somatic mutation affects the body of the person exposed, but not future generations, while genetic mutation affects future generations, but not the body of the person exposed

66
Q

What is total dose in radiation injury?

A

Total dose refers to the quantity of radiation received, or the total amount of radiation energy absorbed. More damage occurs when tissues absorb large quantities of radiation.

67
Q

What is dose rate?

A

Dose rate is the rate at which exposure to radiation occurs and absorption takes place (dose rate = dose/time). More radiation damage takes place with high dose rates because a rapid delivery of radiation does not allow time for the cellular damage to be repaired.

68
Q

How does the amount of tissue irradiated affect radiation injury?

A

The amount of tissue irradiated refers to the areas of the body exposed to radiation. Total-body irradiation produces more adverse systemic effects than if small, localized areas of the body are exposed.

An example of total-body irradiation is the exposure of a person to a nuclear energy disaster.

69
Q

What is cell sensitivity in the context of radiation injury?

A

Cell sensitivity indicates that more damage occurs in cells that are most sensitive to radiation, such as rapidly dividing cells and young cells.

70
Q

How does age affect susceptibility to radiation damage?

A

Age plays a role in susceptibility to radiation damage, with children being more susceptible to radiation damage than adults.

71
Q

What units are used to define three quantities of radiation?

A

Unit for exposure: Si unit: C/kg and roentgen-traditional unit

Unit for Dose: Si unit: gray (Gy) or J/Kg
rad - traditional unit

Unit for dose equivalent: Si unit: Sievert (Sv) rem - traditional unit

72
Q

What are the three quantities of radiation defined by units?

A

Exposure, Dose, and Dose Equivalent.

73
Q

In the context of the three quantities of radiation, What does exposure refer to?

A

Exposure refers to the measurement of ionization in air produced by x-rays.
Measures the amount of energy that reaches the surface of an organism

74
Q

What is the SI unit for exposure?

A

C/kg.

75
Q

What is the traditional unit for exposure?

A

Roentgen.

76
Q

In the context of the three quantities of radiation, How is dose defined?

A

Dose can be defined as the amount of energy absorbed by a tissue.

77
Q

What is the SI unit for dose?

A

Gray (Gy) or J/Kg.

78
Q

What is the traditional unit for dose?

A

Rad.

79
Q

In the context of the three quantities of radiation, What is dose equivalent?

A

Dose equivalent is used to compare the biologic effects of different types of radiation.

80
Q

What is the SI unit for dose equivalent?

A

Sievert (Sv).

81
Q

What is the traditional unit for dose equivalent?

A

Rem.

82
Q

“The risks from dental imaging are not significantly greater than

A

the risks of other everyday activities in modern life.” pg 28

83
Q

The critical organs at risk from dental imaging include

A

the thyroid gland and active bone marrow. The skin and eyes may also be considered critical organs.

84
Q

What is the impact of using digital sensors on radiation exposure?

A

Using digital sensors reduces radiation exposure by decreasing exposure time by 50% to 90% compared with conventional radiography.

85
Q

How does the choice of film affect radiation exposure?

A

The use of F-speed film instead of D-speed reduces the absorbed dose by 60%.

86
Q

What is the effect of collimation on radiation exposure?

A

Radiation exposure can be limited by using rectangular collimation, which reduces the absorbed dose by 60% to 70% compared to round collimation.

87
Q

How can technique influence radiation exposure?

A

Increasing the target-receptor distance and using the paralleling technique can reduce the skin dose.

88
Q

What factors reducing exposure during dental imaging?

A

Receptor choice
Collimation
Technique

89
Q

The average annual radiation dose per person in the U.S.

A

6.2 millisieverts

90
Q

What is a dosimeter?

A

A dosimeter is a small device worn by dental professionals to monitor their exposure to radiation.

91
Q

Why is monitoring radiation exposure important for dental professionals?

A

Monitoring radiation exposure helps ensure that dental professionals stay within safe limits, which is crucial for long-term health.

92
Q

What are the risks of excessive radiation exposure?

A

Excessive exposure to radiation can increase the risk of cancer and other health issues.

93
Q

How do dosimeters contribute to safety in dental clinics?

A

By using dosimeters, we can make sure that everyone in the clinic is working safely.

94
Q

What should be done regarding dosimeter usage during pregnancy?

A

Change checks from Every 3 months to 1 month, inform the program director and main faculty.

95
Q

What information must dosimeters have?

A

Dosimeter badges must have each individual’s first and last name.

Radiology (12 decks)

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