Radiology Ii

Front 1

what is the difference btw radiation and radioactivity

Back 1

radiation: is the emission and propagation of energy through space or a substance in the form of waves or particles
Radioactivity: the process by which certain unstable atoms or elements undergo spontaneous disintegration or decay, in an effort to attain a more balanced nuclear state

Front 2

ionizing radiation is radiation that is capable of producing ions by removing or adding an electron to an atom. what are the 2 ways that ionizing radiation is classified

Back 2

1. particulate radiation: tiny particles of matter that possess mass and travel in straight lines at high speeds. transmit kinetic E
2. electromagnetic radiation: propagation of wave like energy (without mass)

Front 3

A grouping/ classification of electromagnetic radiation’s according to their physical properties:
Wavelength
Energy
Frequency

Back 3

electromagnetic spectrum
remember that electromagnetic radiation's are PURE energy w/o mass/weight

Front 4

in this particle concept electromagnetic radiations are discrete bundles of energy that travel with a wave like motion called what

Back 4

photons or quanta of radiation

Front 5

energy an electron develops when it is attracted by a potential diff. of 1 volt

Back 5

Energy measured in electron volts (eV) = physical prop. of electromagnetic radiation

Front 6

I am a physical property of electromagnetic radiation that is measured in Hertz or cycles per second

Back 6

Frequency = # of wave crests passing a viewing pt. in one sec

Front 7

what wavelengths have high energy, and high freq = high penetrating ability

Back 7

short wavelengths (electomagnetic radiation)

Front 8

what wavelengths have Low energy and low freq = poor penetrating ability

Back 8

long wavelengths (electomagnetic radiation)

Front 9

What are forms of electromag. radiation that have the ability to remove electrons from the orbits of atoms creating an ion pair referred to

Back 9

ionizing radiation

Front 10

what properties do all energies of electromagnetic spectrum share?

Back 10

1. have no mass or weight
2. have no electrical charge
3. travel at the speed of light
4. travel as both a particle and a wave
5. propagate a magnetic field at right angles to the electric field
6. have diff. measurable energies (freq. and wavelengths)

Front 11

In the electromagnetic spectrum ONLY high energy radiations are capable of ionization. name these ionizing types of electromagnetic radiations

Back 11

cosmic rays, gamma rays and xrays

Front 12

Matter is anything that occupies space and has mass. when matter is altered what results

Back 12

ENERGY!
remember that the fundamental unit of matter is the atom

Front 13

what electron shell is located closest to the nucleus and has the highest energy level

Back 13

K shell

Front 14

how is the binding energy (attraction btw. the pos. nucleus and the neg. electrons) of an electron determined

Back 14

by the distance between the nucleus and the orbiting electron
remember the strongest binding energy is found closest to the nucleus in the K shell

Front 15

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

Back 15

ionizing radiation classified into particulate radiation and electromagnetic radiation

Front 16

particulate radiation, a form of ionizing radiation, are tiny particles of matter that possess mass and travel in straight lines and at high speeds, transmitting kinetic energy. Name the types of particulate radiation

Back 16

1. electrons: beta particles (from nucleus from the nucleus of radioactive atoms) or cathode rays (streams of high-speed electrons that originate in an x-ray tube )
2. alpha particles
3. protons
4. neutrons

Front 17

name the types of electrom magnetic radiations

Back 17

- cosmic rays
-gamma rays
- xrays
-UV rays
-visible light
-infrared
-radar waves
- microwaves
- radiowaves

Front 18

this measurment determines the energy and penetrating power of radiation

Back 18

wavelength: the shorter teh distance btw the crests the sorter the wavelength and the highter the energy and ability to penetrate matter

Front 19

true or false frequency and wavelength are directly related

Back 19

False! they are inversely related. if the freq. of the wave is high the wavelength will also be short

Front 20

I am the heart of the xray generating system. I am a glass vacuum and am made up of a leaded glass housing, neg. cathode and pos. anode

Back 20

xray tube

Front 21

what parts of the xray tube are found of the neg. cathode

Back 21

consists of:
tungsten filament: coiled wire made of tungsten which produces electrons when heated
- molybdenum cup: focuses the electrons into a narrow beam and directs the beam across the tube toward the tungsten target of the anode

Front 22

what is the purpose of the cathode

Back 22

supply the electrons necessary to generate xrays. in the tube the electrons produced are accelerated toward the pos. anode.

Front 23

what components of the xray tube will you find at the anode, positive electrode

Back 23

consists of:
- a wafer thin tungsten target: which serves as a focal spot and converts electrons into xray photons
-copper stem: functions to dissipate the heat away from the tungsten target

Front 24

what is the purpose of the pos. anode

Back 24

to convert electrons (received from the cathode) into x ray photons

Front 25

what energy is used to make xrays.

Back 25

electricity. consisting of a flow of electrons through a conductor

Front 26

electrical current is termed direct current or alternating current how do these differ and which does the xray tube utilize

Back 26

direct current is when electrons flow in one direction through the conductor. alternating is an electrical current in which electrons flow in 2 opp. directions
the x-ray tube performs its own RECTIFICATION: coversion of alternating current to direct ensuring that the current is always flowing in the same direction from cathode to anode

Front 27

true or false? voltage is the measurement of the # of electrons moving through a conductor. this is how current is measured

Back 27

False
this is the def. of amperage

Front 28

t/f voltage is the measurement of electrical force that causes electrons to move from a neg. pole to a pos. one

Back 28

true

Front 29

where will you find the step down transformer

Back 29

at the cathode: used to dec. the voltage from the incoming 110-220 line voltage to 3-5 volts used by the filament

Front 30

what is the thermionic emission

Back 30

release of electrons from the tungsten filament when the electrical current passes through and heats the filament. the outer shell electrons of the tungsten atom acquire enough energy to move away from the filament and form an electron cloud

Front 31

In the photoelectric effect there is collision of an x-ray photon with an inner shell electron. Ionization takes place but there is NO scatter produced. How is this possible

Back 31

In the photoelectric effect Absorption is occuring = total transfer of energy from the xray photon to the atoms of matter through which xray beam passes!
*** there is no scatter b/c the xray photon has given up all its KE to orbital energy which is absorbed and ceases to exist

Front 32

there are 2 types of scatter compton scatter and coherent scatter. which one accounts for 62% of the scatter that occurs

Back 32

compton scatter

Front 33

what type of scatter has interaction w/ an outer shell electron, but there is NO change in atoms, No loss of energy and NO IONIZATION occurs

Back 33

coherent scatter
the xray photon was low energy its interaction with the outer electron resulted in an unmodified atom. The xray photon simply undergoes a change in direction w/o a change in energy

Front 34

In this type of scatter there is interaction with an outer electron. the xray photon is of high energy, its collision results in loss of energy and ejects the electron from its orbit (this electron is scattered) producing neg. charged scattered electron and a pos. charged atom

Back 34

compton scatter: this scatter the xray photon lost energy and an electron was scattered resulting in ionization!

Front 35

what is ionization

Back 35

atom that loses an electron

Front 36

which term describes the process by which unstable atoms undergo a spontaneous disintegration in an effeot to attain a more balanced nuclear state

Back 36

radioactivity

Front 37

what term describes two or more atoms that are joined by chem. bonds

Back 37

molecule

Front 38

Name the types of particulate radiation (tiny particles of matter that possess mass and travel in straight lines and at high speeds)

Back 38

1. electrons:beta particles and cathode rays
2. alpha particles
3. protons
4. neutrons

Front 39

speed of a wave

Back 39

velocity

Front 40

number of wavelenghts that pass a given pt. in a certain amt of time

Back 40

frequency

Front 41

T/F x rays are invisible and cannot be detected by any of teh senses

Back 41

true

Front 42

what is the mass of an xray

Back 42

they have no mass or weight

Front 43

t/f xrays have a neg. charge

Back 43

false they have no charge

Front 44

t/f xrays travel at the speed of light

Back 44

true

Front 45

t/f x ray can be focused to a point and never diverge from a point

Back 45

false
cannot be focused and always diverge

Front 46

what determines whether xrays penetrate or pass through or are absorbed

Back 46

the composition! xrays can penetrate liquids solids and gases

Front 47

T/F xrays travel in a straight line and can be deflected or scattered

Back 47

true

Front 48

T/F Xrays are a form of electromagnetic radiation visible light is not

Back 48

false! they are both forms of electromagnetic radiation

Front 49

T/F xrays have more energy than visible light

Back 49

true

Front 50

T/F xrays have a longer wavelength than visible light

Back 50

false shorter

Front 51

T/F xrays travel more slowly than visible light

Back 51

false

Front 52

what regulates the flow of electrical current to the filament of the xray tube

Back 52

low voltage transformer

Front 53

what is used to inc. the voltage in the high voltage circuit

Back 53

step up transformer

Front 54

which of the following does NOT occur when the high voltage circuit is activated
a. the unit produces an audible and visible signal
b. electrons produced at the cathode are accelerated across the tube to the anode
c. xrays travel from the filament to the target
d. heat is produced

Back 54

C: the xrays are no longer at the filament they electrons are actually a cloud that are surrounding the filament and are directed toward the target

Front 55

where are xrays produced

Back 55

positive anode

Front 56

where does thermionic emission occur

Back 56

negative cathode

Front 57

what accounts for 70% of all the xray energy prod at the anode

Back 57

general radiation: sudden stopping of the high speed electrons when they hit the tungsten target in the anode

Front 58

this type of radiation occurs only at 70 kvp or higher and accounts for a very small part of the xrays produced in the dental xray machine

Back 58

characteristic radiation

Front 59

what do you call radiation that exits the tube head

Back 59

primary radiation

Front 60

what is x-radiation that is created when the primary beam interacts with matter. This radiation is less penetrating

Back 60

secondary radiation

Front 61

what do you call radiation that has been deflected from its path by interaction with matter

Back 61

scatter

Front 62

the interaction of xradiation that results in No scatter but ionization

Back 62

photoelectric effect

Front 63

the interaction of xradiation that results in scatter and ionization

Back 63

compton scatter

Front 64

the interaction of xradiation that results in scatter but no ionization

Back 64

coherent scatter

Front 65

the interaction of xradiation that results in no scatter and no ionization

Back 65

no interaction

Front 66

what term is used to describe the mean energy or penetrating ability of the xray beam

Back 66

quality

Front 67

what controls the quality or wavelength and energy of the xray beam

Back 67

kilovoltage

Front 68

I am a measurement of force that refers to the potential difference between 2 electrical charges

Back 68

Voltage measurement of electrical force that causes electrons to move from the neg. cathode to the pos. anode. Voltage determines the speed of e- that travel from cathode to anode. when increase the speed of e- increases. inc. speed = e- hit target with greater force and E = short wavelength

Front 69

how many KV does a dental radiography require

Back 69

65-100 kV
-less than 65 does not allow adequate penetration whereas more than 100 = overpenetration

Front 70

what is defined as the max. or peak voltage

Back 70

kilovoltage peak

Front 71

I am the overall darkness or blackness of a film. I increase when Kilovoltage peak is inc. and other factors remain constant

Back 71

Density

Front 72

what is contrast

Back 72

how sharply dark and light areas are differentiated or separated on a film

Front 73

what type of contrast will you see when a low kilovoltage peak is used

Back 73

high contrast film = many black areas and many white areas and few shades of gray

Front 74

what type of film contrast do you want for the detection and progression of caries

Back 74

high contrast film

Front 75

what type of contrast will you see when a high kilovoltage peak is used

Back 75

low contrast film = has may shades of gray instead of black and white
- useful for the detection of periodontal or periapical dz

Front 76

what type of film contrast do you want for a the detection of periodontal or periapical dz

Back 76

low contrast film with many shades of gray

Front 77

how is exposure time measured

Back 77

in impulses b/c xrays are created in a series of bursts or pulses. one impulse every 1/60th of a sec.

Front 78

I am the number of xrays produced in the dental xray unit

Back 78

quantity

Front 79

how do you inc. the quantity of xrays produced

Back 79

increase the amperage: determines the amt of e- passing through the cathode filament. An inc. in the # of e- available to travel from the cathode to the anode result in prod. of an inc. # of xrays

Front 80

I am the unit measure of the # of e- , or current flowing through the cathode filament

Back 80

ampere

Front 81

In dental radiography the use of how may mA is required

Back 81

7-15 mA

Front 82

what does milliamperage regulate

Back 82

the temp of the cathode filament.

Front 83

t/f milliamperes and exposre time have an indirect influence on the # of e- prod. by the cathode filament

Back 83

FALSE
Direct influence
mA X exposure time = Milliampere- sec.

Front 84

how would an increase in mA affect density

Back 84

Increase density = darker

Front 85

how would a dec. in mA affect density

Back 85

decrease density = lighter

Front 86

if you inc. the kVp by 15 what do you have to do to the exposure time to maintain diagnostic density of film

Back 86

dec. exposure time by 1/2

Front 87

what is the relationship of exposure time and milliamperage to maintain the diagnostic density of a film

Back 87

they are inversely related to maintain density = when mA is inc. the exposure time must be dec.

Front 88

what is intensity

Back 88

the product of the quantity (# of xray photons and quality (energy of ea. photon) per unit area per unit of time of exposure
intensity = (# photons X E of ea. photon)/ areaX exposure rate

Front 89

what is the unit of measurement used to describe the amt of electric current flowing through the xray tube

Back 89

ampere

Front 90

what would would increase as a result from an increase in milliamperage

Back 90

inc. in temp of the filament and the # of xrays prod

Front 91

increase in milliamperage alone results in a film with

Back 91

inc. density

Front 92

total energy contained in the xray beam in a sp. area at a given time is termed what

Back 92

intensity

Front 93

increasing which factors will increase the intensity of the xray beam

Back 93

- kV
- mA
- exposure time (impulses/sec)

Front 94

what is the half value layer

Back 94

the amount of aluminum needed to reduce xray beam intensity by half
< 70 kVp = 1.5 mm aluminum
70-90 kVp = 2.5 mm of aluminum

Front 95

to reduce the intensity of the xray beam aluminum filter are placed. they filter out the low energy less penetrating longer wave length xrays. what amt of thickness of aluminum is necessary for < 70 kVp

Back 95

1.5 mm of aluminum

Front 96

to reduce the intensity of the xray beam aluminum filter are placed. they filter out the low energy less penetrating longer wave length xrays. what amt of thickness of aluminum is necessary for 70-90 kVp

Back 96

2.5 mm of aluminum