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Flashcards in Ch 2 & 8 Deck (89)
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1

Studies relationships between matter and energy

Physics

2

Has mass and occupies space

Matter

3

The quantity of matter contained in an object

Mass

4

Force used to do work

Energy

5

Smallest particle of an element that still possess the chemical properties of that element

Atom

6

Simple substances

Element

7

Complex substances

Compound

8

A material that has definite constant composition
Simple vs complex, elements vs compounds, atoms vs molecules

Substance

9

Two or more substances combined

Mixture

10

Smallest particle of a compound possessing characteristics of the compound

Molecule

11

3 states of matter (dependant upon varying degrees of molecular attraction largely due to temperature)

Solid
Liquid
Gas

12

E=mc^2

Law of conservation of energy (E = energy, m = mass, c = speed of light)

13

Unit of energy

Joule

14

Energy is emitted and transferred through matter; heat and light both come from the sun

Radiation

15

Mini solar system
Electrons don't orbit perfectly, more like beehive

Bohr (1913)

16

Small dense center of atom that contains nucleons, protons and neutrons

Nucleus

17

Electrons can't be divided
Protons and neutrons made up of quarks
M theory (string theory): links this and relativity

Quantum physics

18

Distinguishes elements by number of protons contained in nucleus

Atomic number (Z#)

19

Atoms that have the same number of protons in the nucleus but differ in the number of neutrons

Isotope

20

Adding or removing of electrons from an atom
X-ray photons can interact with atom, results in the ejection of electrons
Changes charges between atoms
Causes disruptions in body's metabolic relationships (can harm patient) so exposing patients to this radiation thus requires order from licensed practitioner

Ioniziation

21

An atom that has gained or lost an electron

Ion

22

How many protons and neutrons in atom, neglects mass of atom's electrons
Mass of proton 1836 times greater than electron, mass of neutron 1838 times greater than electron

Mass number (A#)

23

Defines location where electron might be at any given time

Orbital

24

Chemical combining characteristics that describe how an atom will bond with other atoms
+1 atoms gives up and electron, -1 atom gains an electron

Valence

25

Energy needed to eject an electron from an atom, how tightly bound electrons are bound to the nucleus of that particular atom
Related to how close electron is related to nucleus
Increases as atomic number increases
K shell energy greatest (electrons bound tighter than in other shells)
Depending on how many protons are in the nucleus, the binding power will be stronger the higher the proton number (ex: H vs lead)
Atoms have different number of protons in the nucleus which affect how tightly bound electrons will be
Unit: electron volts (eV); energy of one electron when accelerated by one volt = keV

Electron binding energy (Eb)

26

Atom never has more than eight electrons in its outer shell, for this reason atoms begin to fill in next shell before maximum is reached
Atom with eight electrons in outer shell chemically stable (inert)

Octet rule

27

Ability to do work, force acting upon object over distance expends this
Work = force x distance

Energy

28

Action of physical movement

Mechanical energy

29

2 types of mechanical energy

Potential
Kinetic

30

Energy released from a chemical reaction
Ex: body converts this energy from food into mechanical energy or mood; battery converts this energy into electrical energy

Chemical energy

31

Results from movement of molecules, temperature measures it
Ex: toaster converts electrical energy to this

Heat/thermal energy

32

Electricity, results from movement of electrons in conductor
Ex: light bulb converts electric energy to light

Electrical energy

33

Obtained by breaking bonds between particles within nucleus
Ex: nuclear power plants convert this energy to electricity

Nuclear energy

34

Combination of electric and magnetic fields travelling through space, results from acceleration of a charge
Can travel through medium or vacuum (x-ray tube = vacuum)
Wave/particle duality
Can cause excitation/ionization

Electromagnetic (EM) energy

35

EM travels in waves and there are little particles within each wave

Wave/particle duality

36

The distance between any two successive points on a wave; distance between two peaks

Wavelength

37

Number of waves that pass a particular point in a given time frame

Frequency (hertz, Hz)

38

Intensity of the wave defined by its maximum height

Amplitude

39

Waves are disturbances in a medium; ex: ocean, sound, etc.
Wavelength: angstrom
Frequency (v): cycles per second (Hz)

Wave theory

40

Frequency and wavelength are inversely related
Velocity = frequency x wavelength (V = v x wavelength)
Velocity of all EM radiation is c, c = 3 x 10^8 m/s
c = v x wavelength

Wave equation

41

High frequency, high energy EM radiation
Interacts like particle when contacting matter
Photon (bundle of energy) energy and frequency directly related
When bundle of energy interacts with something, it's able to break it apart; different bundles of energy in each x-ray
If frequency doubled, energy doubles; E=hv

Particle theory

42

Who discovered x-rays and when?

Wilhelm Conrad Rontgen in 1895

43

12 x-ray properties

Penetrating and invisible form of EM radiation (can't be seen, stopped by lead)
Electrically neutral (not affected by electric or magnetic field)
Polyenergetic or heterogeneous energies (various energies/wavelengths)
Release heat when passing through matter
Travel in straight lines
Travel at speed of light
Can ionize matter
Cause fluorescence in certain crystals
Cannot be focused by lens
Affect photographic film
Produce chemical and biological changes in matter (patients) through ionization and excitation
Produce secondary and scatter radiation

44

2 responsibilities of radiographers

Minimize dose
Protect patients and others from unnecessary exposure

45

2 sources of ionizing radiation

Natural
Man-made

46

2 groups of ionizing radiation

Particulate
Electromagnetic

47

High-energy electrons, neutrons and protons
From radioactive decay
Alpha and beta particles
Used in nuc med

Particulate radiations

48

High-energy helium nucleus (two protons and two neutrons)
Decaying radioactive material
Large amount of mass and charge
Can travel 5 centimeters (cm) in air, not very harmful external source but if injected in you it is one of the worst types of radiation
Weighting factor of 20

Alpha particles

49

2 types of particulate radiation

Alpha
Beta

50

Electrons from decaying radioactive material
Little mass and charge
Can travel 10-100 cm in air, not as dangerous as alpha

Beta particles

51

2 types of biologic damage

Direct interaction
Indirect interaction

52

X-rays interact with water molecules which produce free radicals that cause damage
More damage done in diagnostic field

Indirect interaction

53

2 classifications of biological effects of ionizing radiation

Somatic
Genetic

54

Evident in individual, w/in person who receives rad (patient or radiographer)
Ex: burns, erythema (redness), cataracts, cancer

Somatic

55

Evident in offspring of individual
Birth defects

Genetic

56

6 things influenced by biological effects of ionizing radiation

Total dose received
Rate of dose
Age at exposure
Type of radiation
Sensitivity of cells
Body part irradiated

57

2 sources of ionizing radiation exposure

Natural
Man-made

58

3 natural sources of ionizing radiation exposure

Cosmic radiation
Terrestrial radiation
Radionuclides naturally present (internal and external, injected in body for nuc med scans)

59

6 man-made sources of ionizing radiation exposure

X-rays
Radiopharmaceuticals
Consumer products (smoke detectors)
Air travel (closer to sun)
Nuclear fuel production
Fallout

60

5 major areas of radiation exposure in U.S.

Ubiquitous background, including Radon
Medical procedures
Consumer products
Industrial and security activities
Occupational exposure

61

Number of ionizations in given quantity of air
When you make an exposure, there are a bunch of photons that come out of the tube and through air and cause ionization
Exposure in air; quantity of x-rays

Exposure

62

“The quantity of x-rays or gamma rays required to produce a given amount of ionization charge in a unit of mass air”; used in inverse square law

Roentgen (R)

63

Units of exposure

1 R = 2.58 x 10-4 C/kg
Roentgen (R)

64

Measures amount of energy absorbed
Unit can be used to measure any material

Absorbed dose

65

Conventional unit of absorbed dose

1 rad = 100 ergs/gm

66

SI unit of absorbed dose

1 Gray (Gy) = 1 Joule/kg

67

Kinetic Energy Released in Matter
Radiation interacts with matter: energy carried by photon is transformed to kinetic energy to particles (electrons)
At diagnostic energies equivalent to dose (rads/gray)
Unit Gy

Kerma

68

Kinetic energy released per unit mass of air
Used to describe tube output ant input to image receptors
This of 1 cGy = 1 rad
Equivalent to 1 R of exposure

Air kerma

69

Total amount of energy deposited in matter
Ex: CT Abdomen
1 section delivers dose of 1 rad, 20 slices total
Tissue volume of each section 1 rad = 20 rad
No radiation in CT

Integral dose

70

Product of absorbed dose in tissue and radiation weighting

Equivalent dose (Ht)

71

Different types of ionizing radiation produce different biological responses
X-rays have weighting factor of 1

Radiation weighting

72

Conventional unit of equivalent dose

rem

73

SI unit of equivalent dose

Sievert (Sv)

74

Sum of equivalent doses of specific tissues
Not all tissues are equally sensitive to radiation

Effective dose (E)

75

Describes quantity of radioactive material
Expressed as number of radioactive atoms to decay per unit time
Nuc med

Activity (A)

76

Conventional unit of activity

Curie (Ci)
1 Ci = 3.7 x 1010 disintegrations per second (dps)

77

SI unit of activity

Becquerel (Bq)
1 Bq = 1 dps

78

Dose-measuring device

Dosimeter

79

2 classifications of dosimeters

Field survey instruments
Personnel monitoring devices

80

3 types of field survey instruments

Geiger-Mueller survey instruments
Scintillation detection devices
Ionization chamber instruments

81

Gas-filled detector (volume of gas between two electrodes)
Ionizing radiation creates ion pairs in gas
Used to demonstrate presence of radiation
Not for precise measurement
Most effective with particulate radiation
Common use in nuc med
Least effective in detecting x- or gamma radiation

Geiger-Mueller Survey Instruments (GM counters)

82

Emit light when stimulated by ionizing radiation
Light converted to electric signal
Commonly used in nuclear medicine and CT scan equipment

Scintillation detection devices

83

Diagnostic
Used to evaluate equipment performance, leakage radiation and patient exposure
Gas filled chamber, anode, cathode & automatic readout
Configuration
Mechanism of action

Ionization chamber instruments

84

Provided to workers who could accumulate 1/10 of recommended dose limit
Should be worn at level of collar

Personnel Monitoring Devices

85

4 personnel monitoring devices

Optically stimulated luminescence (OSL) dosimeter
Film badge dosimeter
Thermoluminescent dosimeter (TLD)
Pocket dosimeter

86

Most common type of personnel monitor
Detector: thin layer of aluminum dioxide
Laser light processing of aluminum dioxide causes luminescence (level of luminescence proportional to amount of exposure received)
Filters of copper and tin and an open window demonstrate energy of exposure and if exposure occurred while static or in motion
Issued on monthly or quarterly basis
Sensitive to 1 millirem (mrem): picks up on very small amount of radiation (better than others)
Environmentally stable and durable

Optically stimulated luminescence (OSL) dosimeter

87

Detector: two pieces of film in light tight packet
Packet placed in holder with filter elements (copper, cadmium, and aluminum; filters provide information on energy of radiation)
Film processed and optical density evaluated
Demonstrates amount of exposure
Sensitive to 10 mrem, readings under 10 mrem not detectable (reported as M)
Environmentally sensitive to heat, humidity, pressure, prolonged exposure to light

Film Badge Dosimeter

88

Detector: lithium fluoride crystals
Crystals store energy when exposed to ionizing radiation and release stored energy when heated as visible light
Amount of light released proportional to amount of exposure
Sensitivity similar to film badge: 10 mrem
Environmental sensitivities also similar to film badges
Heat, humidity, temperature, pressure, and prolonged exposure to light
Compact design
Desirable for extremity badges
Small & often made into rings

Thermoluminescent dosimeter (TLD)

89

Ionization of air in small chamber
Readout occurs digitally
Can be read from display on side of dosimeter
No permanent record

Pocket dosimeter
Electronic Personal Dosimeter