Introduction Flashcards

1
Q

What is a radiograph?

A
  • an image produced by X-rays passing through an object and interacting with the photographic emulsion on a film
  • if a digital image is being formed, the x-rays affect a sensor or a phosphor plate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Who discovered X-rays?

What was the first x-ray image and when?

When were radiographs first used in Dentistry?

A

Wilhelm Conrad Roentgen - November 1895

  • image sof his wifes hand - December 1895
  • first used in dentistry in 1896 and could detect caries and periapical pathology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an atom made up of?

Comment on the shells:

A

Nucleus:

  • protons (positive charge)
  • neutrons (no charge)

Electrons - negative charge: orbit around nucleus in different energy shells:

  • K, L, M outer shells
  • move in predetermined shells with different energy levels
  • can move from shell to shell but cannot exist between shells: forbidden zone
  • energy is required to remove electrons fron atom and must overcome binding energy which keeps it in its shell
  • greatest binding energy on outermost shells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are isotopes?

Radio-isotopes?

What are ions?

Anion?

Cation?

A

Isotopes: atoms with the same number of protons but different number of neutrons

Radio-isotope: isotopes with unstable nuclei which undergo radioactive disintegration

Ions: charged atom or molecule, number of electrons do not equal number of protons

Anion: negative charge if more electrons

Cation: positive charge if more protons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an alpha particle?

Beta particle?

Gamma radiation?

A

Alpha particles:

  • 2 protons, 2 neutrons (helium nucleus)
  • large, positive charge, slow, penetrate 1-2mm in tissue, cause extensive ionisation

Beta particles:

  • fast electrons, snall, negative charge, fast, 1-2cm penetration in tissue, ionisation damage

Gamma rays: electromagnetic radiation

  • very fast, can pass through tissue, also cause ionisation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When does ionisation become a problem?

A
  • when it occurs in living cells
  • can cause damage to tissues e.g. cataracts
  • can cause damage to DNA directly or produce chemicals that do damage e.g. tumours or cancer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give an overview of the electromagnetic spectrum:

A
  • stream of photons that have no mass
  • travel at speed of light 3.0x108
  • photons can have ddifferent amounts of energy –> affects properties
  • energy measured in eV
  • frequency - cycles per second or Hertz
  • wavelength measured in metres or nm
  • visible light 400-700nm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the domestic electricity supply?

A
  • 220-240V
  • 50 Hz
  • 13 amp

1V is the potential difference between 2 points on a conducting wire carrying a constant current of 1amp, when the power dissipated between the points is 1 watt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly