Final Exam Flashcards
What is the standard unit for radiation intensity?
Roentgen (R)
What are the cardinal rules?
- Time
- Distance
- Shielding
What is the purpose of tube house?
To…
- shield and cool x-ray tube
- to prevent excessive radiation exposure
What determines the mAs of an atom?
The combination of protons and neutrons (Atomic mass #)
All group atoms have the same # of ____?
Same # of electrons on the outermost shell
Define ionic bonding
When one atom either gives up or gain an electron causing the attraction of opposing charges
What are the 3 components of an atom?
- protons
- neutrons
- electrons
When were x-rays discovered?
November 8th, 1895
What is the purpose of permanent equipment?
To provide stability and reliability for routine imaging
What is the SI unit for mass?
Kilogram
What is the relationship between frequency and wavelength?
Indirectly proportional
Why study the atom?
Because interactions in the x-ray tube, and interactions with a human body all happen at an atomic level
Upright exams are done where in the examination room?
On the wall Bucky
What is the outermost shell letter?
Shell letter Q
Define fundamental quantities?
They are independent physical quantities that serve as the foundation for measuring other quantities such as … length, mass, time
What is the relationship between frequency and wavelength?
Indirectly proportional
Inverse square law question
Define isobars
Different # of protons but same # of protons and neutrons
What is the relationship between frequency and wavelength?
Indirectly proportional
Inverse square law question
What is the unit for occupational dose?
Rad - Gray
What is the unit for occupational dose?
Rad - Gray
Define wave particle duality
Exhibits properties of both particle and a wave depending on its energy and environment
Define inverse square law
What is not considered part of the electromagnetic spectrum?
Not considered is …
- sound waves
What is the SI unit for patient dose?
Gray
What is the function of the collimator?
To restrict and shape a beam to a specific area to minimize unnecessary exposure
What did Roentgen contribute to the medical field?
He discovered x-rays
Define radioactive element?
Is a radioactive material that gives off a form of energy that travels in waves or particles called radiation
What is the purpose of mAs and kVp?
mA controls the quantity if x-rays produced while kVp controls the quality of the x-ray beam
What is the advantage of mobile equipment?
It can be used in many rooms like ER’s, surgical rooms, ICU’s etc.
What is the closet shell in the nucleus?
K shell
Define molecule
Made up of two or more atoms
Define inverse square law
Define ionization
The process in which an atom gaining or losing electrons
What is the SI unit of different types of radiation?
Sievert
The nucleus contains what?
Protons and neutrons
Radio waves are used in..?
MRI
Who established the code of ethics?
American Society of Radiology Technologists (ASRT)
How are x-rays and gamma rays different?
They ionize
Define inertia
the property of an object with mass that resists a change in its state of motion.
Helium contains what particles?
2 protons
2 neutrons
2 orbiting electrons
Lead shutters are part of?
Collimator
Define potential energy
is energy in a stored state
Which type has the longest wavelength?
Radio waves
What are the cardinal rules?
- Time
- Distance
- Shielding
Define ALARA
As Low As Reasonably Achievable
Define wavelength
is the distance from one peak to another
Define AC
Alternating Current
What is the anode heel affect?
the “heel” of the target is partially placed in the path of the x-ray beam produced, causing absorption and reduced intensity of the beam on the anode side
Define line focus principle
a large actual focal spot is maintained to spread heat load and create a small effective focal spot to improve image detail
Define tube current
the amount of electric current flowing through the X-ray tube
What are the functions of a step down transformer?
- reduce kilivoltage to voltage
What is needed for the flow of electrons on a conductor?
Voltage and an unbroken circuit
Define line focus principle
a large actual focal spot is maintained to spread heat load and create a small effective focal spot to improve image detail
Pathways needs to be ____ for flow of electricity
Closed
What is the advantage of small focal spot?
Improve sharpness of the image
What are the different parts of the circuit?
- primary circuit
- secondary circuit
- filament circuit
Volts measures what?
Electric potential difference
Like poles ____, opposites ____
- repel
- attract
Define motor
Important part to facilitate efficient heat dissapation
What material lines the tube housing?
Lead
Selecting focal spot means?
Selecting which filament heats up
Define resistor
Controls the flow of electrons
Define autotransformer
It’s device that controls voltage adjustment
Define semi conductor
Material with electrical conductivity between that of a conductor and an insulator
What is the last step of x-ray production?
- Filaments heat up forming electron cloud
- electrons are sent towards anode target
- once target is hit, energy is released in the form of x-ray photons
- then x-rays are produced
Define molybdenum
used as the disc base and core because it has a low thermal conductivity and it is a light but strong alloy
What percentage of energy is x-rays?
1% x-rays, 99% heat
Define ripple
the variation in the voltage output of an X-ray generator
Purpose of the tube housing?
To…
- shield and cool x-ray tube
- to prevent excessive radiation exposure
Define rectification
The process of converting alternating current to direct current
Put x-ray production events in order…
Filaments heat up forming electron cloud
- electrons are sent towards anode target
- once target is hit, energy is released in the form of x-ray photons
- then x-rays are produced
Define auto transformer
It’s device that controls voltage adjustment
Define anode heel affect
the “heel” of the target is partially placed in the path of the x-ray beam produced, causing absorption and reduced intensity of the beam on the anode side
What is the location of filaments
Filament circuit
Advantage of rotating anode
Spreads heat
Location of timer switch?
Primary circuit
Parts of the anode includes …?
- copper shaft
- Molybdenum disc base and core
- Tungsten used due to very high melting point
Define ohm’s law
The potential difference (voltage) across the total circuit or any part of that circuit is equal to the current
Define ferromagnetic
are strongly attracted to magnetic materials
Location of the stator?
In a rotating anode
Define magnetism
The ability of a material to attract iron, cobalt, or nickel
Define ripple
the variation in the voltage output of an X-ray generator
Define line compensator
a device usually wired to the autotransformer that automatically adjusts the power supplied to the x-ray machine to 220 volts
Why is tungsten used?
- Tungsten used due to very high melting point
What is used to cool x-ray tube?
Oil baths and cooling fans
Anode is made up of ?
A rotating tungsten-coated molybdenum disc mounted on a copper shaft with a molybdenum core
What is the Purpose of the focusing cup?
Focus target to anode
Define AC
Alternating current
What is used to cool x-ray tube?
Oil baths and cooling fans
Pic of photoelectric interaction
How to minimize occupational exposure?
Apply cardinal rules
Which interaction is the source of occupational exposure?
Compton scattering
Relationship between filtration and quantity?
Inversely proportional
When is a characteristic photon produced?
When an outer shell fills in vacancy places
If kVp is 75 … what is the energy range?
0-75 KeV range
Compton results in …?
results in the loss of an electron and ionization of the absorbing atom
Relationship between distance and quantity?
Inversely proportional
When do you get a characteristic photon?
When an outer shell electron fills an inner shell vacancy
Define x-ray quantity
of x-ray photons
Pic of Brems
What happens to the emissions spectrum when we go from high frequency to single phase generator?
The emission spectrum shifts
Secondary photon is produced by … ?
Compton effect
Define cascade effect
where an initial action or event triggers a series of ripples
Relationship between quantity and mAs is …?
Directly proportional
Change in the x - axis is change in the …?
Increase in kVp
Define hard beam?
more penetrating and less likely to be absorbed by tissues, resulting in a higher-quality image
Picture … graph of increase in mA
What is needed to produce x-ray image?
What is the primary source of occupational exposure?
Compton scattering
Define x-ray quantity
of x-ray photons
Define cascade
where an initial action or event triggers a series of ripples
Emission spectrum graphs what?
the pattern of lines seen when light from a substance is separated out into its different wavelengths
Define classical scattering photons
incident x-ray photon interacts with an orbital electron of a tissue atom and changes direction
Photoelectric interactions occur on ___?
The bone
What happen during photoelectric interactions?
The photo is completely absorbed and its energy is transferred to an electron that is removed from the electron cloud
Transmitted x-rays appear ….?
Light shade of gray
Define Compton scattering
An incident x-ray photon enters a tissue atom, interacts with an orbital electron and removes it from its shell. The incident photon loses up to one third of its energy and is usually deflected in a new direction.
Which factors change appearance of x-ray image?
Focal spot
Relationship is between mA and quantity
Directly proportional
Define transmitted radiation
the passage of electromagnetic radiation through a medium without significant absorption or reflection.
How is quality measured?
HVL ( Half Value Layer)
Air is considered radiolucent or radioapauge?
Radiolucent
Picture of Compton interaction
Graph of increase in kVp
Inverse square law question
Define transmitted radiation
the passage of electromagnetic radiation through a medium without significant absorption or reflection.
Relationship between quality and kVp
Directly proportional
Does Pair production happen in x-ray diagnostic range?
No
How to minimize radiation exposure?
Apply cardinal rules
Inverse square law question
What percentage is x-rays?
1% x-rays, 99% heat
Inverse square law question
Inverse square law question
Energy range of Compton is?
20-40 keV
Radiation interaction with bone appears as?
Light gray
Energy range of Compton is?
Energy range of Compton is?
20-40 keV
