Ch. 1 Concepts of radiologic science Flashcards Preview

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Flashcards in Ch. 1 Concepts of radiologic science Deck (131):
1

All things can be classified as...

matter or energy

2

Define matter

anything that occupies space and has mass

3


All physical objects are composed of...

matter

4

All matter is composed of foundational building blocks called

atoms

5

Define mass.

A primary, distinguishing characteristic of matter that is the quantity of matter contained in any physical object

6

Define weight

the force exerted on a body under the influence of gravity

7

Mass is measured in..

kg

8

What are the fundamental, complex building blocks of matter?

atoms and molecules

9

1 kg is equal to...

1000 grams

10

What is the unit of energy in radiology?

eV (electron volt)

11

Define energy

the ability to do work

12

Define chemical energy

energy released by a chemical reaction

13

Name an example of chemical energy

biochemistry..the type of energy is provided to our bodies through chemical reactions involving the foods we eat.

14

Define electrical energy

the work that can be done when an electron moves through an electric potential difference (voltage)

15

What is electric potential difference?

voltage

16

Define thermal energy

the energy of motion at the molecular level. It is the kinetic energy of molecules and is closely related to temperature.

17

What is nuclear energy?

the energy that is contained within the nucleus of an atom

18

What is an example of the uncontrolled release of nuclear energy?

the atomic bomb

19

Define electromagnetic energy

Oscillating electric and magnetic fields that travel in a vacuum with the velocity of light. Includes x-rays, gamma rays, and some nonionizing radiation (such as ultraviolet, visible, infrared, and radio waves.)

20

What is the least familiar form of energy?

electromagnetic energy

21

What kind of energy is used in x-rays?

electromagnetic energy

22

What are types of electromagnetic energy?

x-rays, radio waves, microwaves, ultraviolet light, infrared light, and visible light

23

Can energy be transformed from one type to another?

yes

24

Explain how energy can be transformed in the production of an x-ray.

electrical energy produces electromagnetic energy in the machine which is converted to chemical energy in the film or electrical signal in a digital image receptor.

25

What is the mass-energy equivalence equation?

E=mc2

26

Energy emitted and transferred through space is called...

radiation

27

Visible light, a form of electromagnetic energy, is radiated by the sun and is called...

electromagnetic radiation

28

Matter that intercepts radiation and absorbs part or all of it is called....

exposed or irradiated

29

When a patient is exposed to radiation, they are said to be...

irradiated

30

Define ionizing radiation

any type of radiation that is capable of removing an orbital electron from the atom with which it interacts.

31

Interaction between radiation and matter is called...

ionization

32

Ionization occurs when...

an x-ray passes close to an orbital electron of an atom and transfers sufficient energy to the electron to remove it from the atom

33

What is an ion pair?

the orbital electron and the atom from which it was separated. The electron is a negative ion, and the remaining atom is a positive ion.

34

What is the transfer of energy?

radiation

35

What is the removal of an electron from an atom called?

ionization

36

What are the only forms of electromagnetic radiation with sufficient energy to ionize?

x-rays, gamma rays, and ultraviolet light

37

Other than electromagnetic radiation, what can also ionize?

Some fast moving particles (particles with kinetic energy)

38

What are examples of particle type ionizing radiation?

alpha and beta particles

39

What are the 2 categories of ionizing radiation?

natural environmental radiation and man made radiation

40

What is the annual dose of natural environmental radiation?

3 mSv

41

What is the annual dose of man made radiation?

3.2 mSv

42

What is the unit of effective dose?

mSv

43

What does the unit dose mSv express?

it is used to express radiation exposure of populations and radiation risk in those populations.

44

What are the 4 components of natural environmental radiation?

cosmic rays, terrestrial radiation, internally deposited radionuclides, and radon

45

What are cosmic rays?

particulate and electromagnetic radiation emitted by the sun and stars

46

On Earth, how do cosmic rays intensify?

with altitude and latitude

47

Where does terrestrial radiation result?

deposits of uranium, thorium, and other radionuclides in the Earth.

48

What does the intensity of terrestrial radiation rely on?

the geology of the local area

49

What is the largest source of natural environmental radiation?

radon

50

What is radon?

a radioactive gas that is produced by the natural radioactive decay of uranium that is present in trace quantities in the Earth.

51

All Earth based materials contain...

Radon

52

What does radon emit?

alpha particles

53

Alpha particles are penetrating..T or F?

F, they are not penetrating so they only contribute dose to the lung

54

Natural environment radiation results in how much microgray/hr?

0.02 to 0.1 microgray/hr at waist level which equals 0.2 milligray/yr at the gulf elevations and 1 mGy/yr in the Rocky Mountains.

55

What makes up the largest man made source of ionizing radiation?

diagnostic x-rays at 3.2 mSv/yr

56

Why was there such an increase in man made ionizing radiation between the years 1990-2006?

It was caused because of CT and high level fluoro

57

What is the currently accepted approximate annual dose that results from medical applications of ionizing radiation?

3.2 mSv

58

What % of our annual average radiation dose is attributable to medical imaging?

51%

59

cathode rays are also called...

electrons

60

When did Roentgen discover x-rays?

November 8, 1895

61

What was the plate coated with when Roentgen discovered the rays?

barium platinocyanide

62

What type of material is barium platinocyanide?

fluorescent

63

Who received the first Nobel Prize in physics?

Roentgen in 1901

64

In 1896 Roentgen published the 1st medical x-ray. What was it?

His wife's hand

65

What are the 3 types of x-ray examination?

radiography, fluoroscopy, and CT

66

To provide an x-ray beam that is satisfactory for imaging, you must supply the x-ray tube with a high what?

voltage and electric current

67

How are x-ray voltages measured?

in kVp

68

How are x-ray currents measured?

mA

69

Who invented the fluoroscope?

Thomas Edison in 1898

70

Radiology emerged as a medical specialty because of...

the Snook transformer and the Coolidge x-ray tube

71

What were the early reports of radiation injury?

skin damage, hair loss, and anemia

72

What does ALARA stand for?

As Low As Reasonably Achievable

73

What are metal filters usually made of?

aluminum or copper

74

The use of intensifying screens reduce patient exposure by how much vs. non use?

95%

75

What are the 3 base quantities of measure in physics?

Mass, length, and time

76

Secondary quantities of measure are also called

derived quantities

77

Why is the term derived quantities used?

Because they are derived from the 3 base quantities

78

In radiologic science, special quantities are considered...

exposure, dose, effective dose and radioactivity

79

The second (s) is based on...

the vibration of atoms of cesium

80

When working on problems or reporting answers, what should always be used?

the same system of units

81

Volume=?

V=lwh

82

The dimensions of a box are 30cm x 86cm x 4.2m. Find the volume

V = (0.3m)(0.86m)(4.2m) = 1.1m^3

83

Find the mass density of a solid box 10cm on each side with a mass of 0.4kg.

D = m/v
change 10cm to 0.1m
= 0.4 kg/(0.1m x 0.1m x 0.1m)
= 0.4 kg/0.001m^3
= 400kg/m^3

84

A 9" thick patient has a coin placed on the skin. The SID is 100cm. What will be the magnification of the coin?

M = SID/SOD
M = 100cm/100cm-9"
M = 100cm/100cm - (9" x 2.54 cm/in)
M = 100cm/100cm - (23cm)
M = 100cm/77cm
M = 1.3
The image of the coin will be 1.3 times the size of the coin

85

Define velocity

the measure of how fast something is moving or , the rate of change of its position with time

86

Velocity = ? (formula)

V = d/t

87

What is the velocity of a ball that travels 60m in 4s?

v = 60m/4s
v = 15m/s

88

Light is capable of traveling 669 million miles in 1 hour. What is its velocity in SI units?

v = 6.69x10^8 mi/hr x 1609 m/mi/3600 s/hr
v = 2.99 x 10^8 m/s

89

The velocity of light is constant and is symbolized by...

c

90

Average velocity = ?

Average velocity = initial velocity + final velocity/2

91

Define acceleration

The rate of change of velocity with time

92

acceleration = ? (formula)

a = final velocity - initial velocity/ time

93

What is Newton's first law?

Inertia-a body will remain at rest or will continue to move with constant velocity in a straight line unless acted on by an external force

94

inertia is..

the property of matter that acts to resist a change in its state of motion

95

What is Newton's second law?

Force-the force (F) that acts on an object is equal to the mass (m) of the object multiplied by the acceleration (a) produced.

96

Force = ? (formula)

F = ma

97

Find the force on a 55kg mass accelerated at 14 m/s^2.

(55kg)(14 m/s^2)
F = 770N

98

For a 3600 lb (1636kg) Mustang to accelerate at 15 m/s^2, what force is required?

F = ma
F = (1636 kg)(15 m/s^2)
F = 24,540 N

99

What is Newton's 3rd law?

Action/reaction-for every action, there is an equal and opposite reaction

100

Weight is the product of...

mass and the acceleration of gravity on Earty

101

Weight = ? (formula)

mg

102

What is the unit for weight

N or lb

103

A student has a mass of 75 kg. What is her weight on the Earth? On the moon?

Earth = 9.8 m/s^2
Wt = mg
Wt = 75kg (9.8 m/s^2)
Wt = 735 N

Moon = 1.6 m/s^2
Wt = mg
Wt = 75 kg (1.6 m/s^2)
Wt = 120 N

104

Define momentum

The product of the mass of an object and its velocity

105

Formula for momentum?

p=mv

106

Work= ? (formula)

W = fd

107

What is the unit for work?

Joule (J)

108

Find the work done in lifting an infant patient weighing 90 N (20 lb) to a height of 1.5m.

W = fd
W = (90 N)(1.5m)
W = 135 J

109

Define power

The rate of doing work

110

Power = (formula)

P = work/t = Fd/t

111

What is the unit for power?

J/s which is also a watt (W)

112

A radiographer lifts a 0.8kg cassette from the floor to the top of a 1.5m table with an acceleration of 3 m/s^2. What is the power exerted if it takes 1.0 s?

Multistep problem:
P=work/t
W=Fd
F=ma

F=ma
=(0.8 kg)(3 m/s^2)
= 2.4 N

W=Fd
=(2.4 N)(1.5m)
= 3.6 J

P=work/t
= 3.6 J/1.0s
= 3.6 W

113

What is the formula for kinetic energy?

KE=1/2 mv^2

114

What is the formula for potential energy?

PE=mgh

115

Define heat

the kinetic energy of the random motion of molecules

116

What is the unit of heat?

calorie

117

Define calorie

the heat necessary to raise the temperature of 1g of water by 1 degree C

118

How is heat transferred?

By conduction, convection, and radiation

119

Define conduction

the transfer of heat through a material or by touching

120

Define convection

the mechanical transfer of hot molecules in a gas or liquid from one place to another

121

Define thermal radiation

the transfer of heat by the emission of infrared radiation

122

An x-ray tube cools primarily by...

radiation

123

Convert 77 degree F to Celsius

C = 5/9 (F-32)
= 5/9 (77-32)
=5/9(45)
= 25 degrees Celsius

124

Method to go from F to C and vise versa.

From F to C - subtract 30 and divide by 2
From C to F - double and then add 30

125

What is Air Kerma?

Kinetic energy transferred from photons to electrons during ionization and excitation

126

What is the unit of measure for Air Kerma?

Gy

127

1 J/kg is how many Gy?

1

128

What is absorbed dose?

radiation energy absorbed per unit mass and has units of J/kg or Gy

129

For a given air kerma, the absorbed dose depends on...

the type of tissue being irradiated.

130

Occupational radiation monitoring devices are analyzed in terms of....

Sv

131

Sv is used to express..

the quantity of radiation received by radiation workers and populations