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Dental Hygiene: Radiology > Radiation Physics > Flashcards

Radiation Physics Flashcards

1
Q

Define…
matter
atom
energy

A

matter: anything that occupies space and has mass
atom: fundamental unit of matter
energy: occurs when matter is altered

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2
Q

a nucleus is composed of…

A

protons (positive)
neutrons (no charge)
electrons (negative)

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3
Q

Mass number/atomic weight Vs Atomic number

A

mass number: protons + neutrons
atomic number: number of protons equals number of electrons, is this number

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4
Q

List the letters for the electron orbits/shells

A

K (closest to nucleus and highest energy)
L
M
N
O
P
Q

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5
Q

What are the two ways molecules can be formed?

A

transfer of electrons
sharing electrons between outer shells

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6
Q

Ionizing radiation

A

energy is transmitted through space or matter (able to ionize)
ex// x-rays, gamma rays, alpha and beta particles

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7
Q

Nonionizing radiation

A

may excite stable atoms by raising an orbital electron to higher energy state
ex// visible light, infrared rays

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8
Q

Do we use x-radiation or radioactivity in dentistry?

A

x-radiation

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9
Q

Ion

A

an atom that gains or loses an electron and becomes electrically unbalanced

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10
Q

Negatively charged atom

A

gains an electron from an adjacent atom, more electrons than protons and neutrons

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11
Q

Positively charged atom

A

loses an electron and has more protons and neutrons

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12
Q

Ion pair

A

formed when an electron is removed from an atom

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13
Q

Particulate radiation

A

-tiny particles of matter that possess mass and travel in straight lines at high speeds
-transmit kinetic energy

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14
Q

Electromagnetic radiation

A

-propagation of wavelike energy (without mass) through space or matter
-man made or occur naturally
-magnetic fields at 90 degree angles and oscillating electrons

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15
Q

Beta particles

A

fast moving electrons emitted from nucleus of radioactive atoms

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16
Q

Alpha particles

A

emitted from the nuclei of heavy metals, exist as two protons and neutrons w/out electrons

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17
Q

Cathode rays

A

streams of high speed electrons that originate in the x-ray tube (electrons emitted)

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18
Q

Protons vs neutrons

A

protons: accelerated hydrogen nuclei
mass 1 charge +1
neutrons: accelerated particle
mass 1 no charge

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19
Q

List the properties of electromagnetic radiation

A

-no mass or weight
-no electrical charge
-travels at speed of light
-travels as both particle and a wave***
-propagate an electrical field at rights angles to path of travel
-propagate a magnetic field at right angles to the electrical field
-have different measuring energies

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20
Q

Particle concept of electromagnetic radiation

A

discrete bundles of energy called photons or quanta
-no mass
-no weight
-waves at speed of light
-travels in straight line

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21
Q

Which concept characterizes electromagnetic radiation

A

wave concept

22
Q

Frequency

A

number of wavelengths that pass a given point in a certain amount of time

23
Q

wavelength and frequency are _______ related.

A

inversely (if one is high other is low)

24
Q

long wavelengths=
short wavelengths=

A

lazy
strong
use those first letters to remember😗

25
Q

List the electromagnetic spectrum is order of lowest energy to highest

A

radio
microwave
infrared
visible light
ultraviolet
x-rays
gamma rays

26
Q

Do x-rays have any mass or charge?

A

NO

27
Q

Describe the speed and wavelength of x-rays

A

travels at speed of light
short wavelengths w/ high frequency

28
Q

Describe the path of travel and focus capabilities of x-rays

A

travels path in straight line and can be deflected or scattered
cannot be focused to a point and will always diverge

29
Q

Describe the penetrating power and absorption of x-rays

A

is able to penetrate liquids solids and gases, composition of the substance will effect whether it penetrates or is absorbed
x-rays are absorbed by matter; absorption depends on composition of the matter and the wavelength of the x-ray

30
Q

Describe the ionizing capabilities of x-rays

A

high energy ionizing radiation
interacts with materials they penetrate and cause ionization
*can cause some structures to fluorescence

31
Q

CATNAP

A

CAThode
Negative
Anode
Positive

32
Q

List the components of the x-ray tubehead and their function

A

-metal housing (surrounds xray tube filled with oil)
-insulating oil (prevent overheating through absorption of heat)
-tubehead seal (aluminum or glass covering of tubehead, prevent exit of xray)
-xray tube (generates xray)
-transformer (alters voltage)
-aluminum disks (filters longer wavelengths)

33
Q

Describe the x-ray tube

A

glass vacuum tube with all air removed from it

34
Q

DC vs AC

A

DC: direct current- electrons flow in one direction
AC: alternating current- electrons flow in two opposite directions

35
Q

Rectification

A

conversion of alternation currents (AC) to direct currents (DC)

36
Q

Dental x-ray tubes act as ________.

A

self rectifiers; alternates AC into DC while producing x-rays
*ensures current is always flowing from cathode to anode

37
Q

Amperage

A

measurement of the number of electrons moving through a conductor

38
Q

Voltage

A

measurement of the electrical force that carries electrons from negative to positive poles

39
Q

Low voltage circuits

A

-3 to 5 volts to heat filament
-regulates flow of electrical current to filament
-controlled by mA

40
Q

High voltage circuits

A

-65k to 100k volts
-accelerates electrons from cathode to anode to produce the x-radiation
-controlled by kV

41
Q

Transformer

A

-electromagnetic devices that allows a voltage of alternating current to be changed
-voltage may be increased or decreased
-supplies voltage to filament and anode
-step up, step down, or autotransformer
*routes current to x-ray tube**

42
Q

Thermionic emission

A

occurs when the tungsten filament is heated by a current and electrons are released by the filament

43
Q

List how x-rays are produced

A
  1. current enters control panel when unit turned on
  2. current goes from control panel to the tubehead through extension arm
  3. filament circuit uses 3-5 volts to heat tungsten filament
  4. heating of filament results in thermionic emission
  5. high voltage circuit activated when exposure button pushed
  6. electrons in the cloud accelerated across x-ray tube to anode
  7. cathode directs electrons to tungsten target
  8. electrons travel from cathode to anode
  9. when electrons strike tungsten target the kinetic energy is converted to x-rays and heat
  10. less than 1% is x-rays
  11. heat absorbed by insulating oil
  12. x-rays travel through unleaded glass window, tubehead seal, and aluminum filter
44
Q

General (Braking) Radiation

A

attractive force between the bombarding electron and the nucleus of tungsten atom
consist of x-rays of many different energies and wavelengths

45
Q

Characteristic Radiation

A

high speed electron dislodges an inner shell electron from the tungsten atom and causes ionization of that atom
account for a very small portion of x-rays produced

46
Q

Define primary, secondary, and scatter radiation

A

primary: penetrating xray beam
secondary: x-rays produced when primary beam interacts with matter (less penetrating)
scatter: a form of secondary that is result of xray being deflected

47
Q

No interaction

A

xray photon passes through the atom unchanged
*responsible for making densities on images and allow dental radiology to be possible:)

48
Q

Photoelectric effect

A

xray photon collides with tightly bound inner shell electron, gives up all its energy to eject the electron from its orbit
*responsible for image contrast

49
Q

Compton Scatter

A

*account for most of the scatter radiation
xray photon collides with loosely bound outer shell electron, photon loses some energy and continues in different direction at a lower energy

50
Q

Coherent scatter

A

*aka unmodified scatter
low energy xray photon collides with an outer shell electron, photon has no change in energy only changes direction
*little effect on diagnostic imaging

Dental Hygiene: Radiology (17 decks)

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