Safety Kettering Audio Flashcards
Definition of Thermionic Emission:
Boiling off of electrons, liberation of electrons
Responsible for sending the current for thermionic emission to take place:
Filament Transformer or Step down transformer
Electric potential/potential difference/source of EMF represents the unit of the:
Volt
The unit of electric potential:
Volt
What charge does the anode carry? positive or negative?
positive electrode
What material makes up target surface?
Tungsten Target with Rhenium
Or
Tungsten
The two components that make up the cathode:
filament wires and focusing cup
What charge does the cathode carry? positive or negative?
negatively charged
What material makes up the filament wires?
Thoriated Tungsten
What material makes up the focusing cup?
molybdenum or nickle
99% of the interaction process gets converted to:
Heat (Thermal Energy)
Up to 1% gets converted to:
electromagnetic energy (x-ray photons)
Electrons get converted to: (when they interact with the target surface):
x-ray photons
When electrons interact with the target surface it is called the:
side of conversion
Where do electrons get converted to x-ray photons?
the target surface
Smallest subdivision of an element that maintains all the physical and chemical properties of the element:
Atom
We know that protons are (+) positively charged, nuetrons are no charge or neutral and electrons are negatively charged within the nucleus we call them:
nucleons (properties of the nucleus)
Upside down T is a symbol for:
Perpendicular Central Ray
CR:
Central Ray
IR:
Image Receptor
z
Atomic number
Atomic mass number (A) definition:
number of nucleons or number of protons + neutrons
Atomic number (z) definition:
the number of protons in the nucleus
the electrons and the protons are highley attracted to each other, how come the protons don’t fly out to see the electrons, how come the electrons do not fly inward:
Because you have two counteractive forces competing with each other, syntripical vs syntripical force.
The binding energy of the K-shell of Tungsten?
69.53 kEV or 70 kEV
What is the atomic number of Tungsten?
z=74 (74 protons 74 electrons)
The number of electrons in the last or outermost shell:
valence number
What is the maximum number of electrons you can have in the 3rd shell (M)?
2 (3)^2 2x9= 18 electrons
What is the maximum number of electrons in any one shell?
2n^2
What is the maximum number of electrons in the valance shell?
maximum of 8
The definition of Isotropic Emission:
X-rays are emitted by the focal spot in all directions
The definition of Attenuation:
The reduction of the intensity of the beam as it passes through matter
The definition of Ionization:
The removal of an orbital shell electron
An atom of tungsten, if ionization takes place and drop the electron. The previously uncharged atom will have an electrical charge. After ionization takes place what charge will the atom carry?
positively charged (74 protons 73 electrons)
In x-ray production when x-rays get produced/when x-rays get produced in the tube:
Bremsstrahlung
Characteristic
When x-rays interact with matter:
Compton
Coherent
Photoelectric
Projectile (high speed) electron interacts with the electrostatic field of the (tungsten) nucleus:
Bremsstrahlung
The projectile electron undergoes three processes:
Slows Down
Changes Direction
Loses some of its energy
When the electron becomes under the influence of the nucleus, what continues on:
the momentum effect of the production of an unknown ray (x-ray)
Bremsstrahlung x-ray emission*
Average x-ray energy beam about:
30% of peak
In order to produce characteristic radiation:
70 kV and above
If the technologist does a hand x-ray at 60 kVp:
the electron can not ionize an remove it
4 requirements of production x-rays:
Source of free electrons
Accelerate electrons across the tube
Focus the electrons
Deceleration
Send a current to the wire, the wire gets hot and electrons get boiled off through in the process of:
Thermionic Emission
The _____ determines the amount of current that will be sent to the filament (step down transformer)
MA
As the number of secondary turns decreases voltage:
Decreases
Current increases proportionally
Rhenium:
Bigger stronger faster to stand up to the high speed electrons bombarding it constantly
Atoms exist with a net nuetrality of:
0
We produce two types of radiation in the diagnostic imaging world;
Bremsstrahlung
Characteristic
When there is an interaction with the k-she’ll, ionization takes place and the L shell fills the void:
Characteristic Interaction
All photons always maintain four properties:
Frequency
Wavelength
Velocity
Amplitude
An x-ray is considered to be:
Photon
A light photon is considered an
X-ray
X-radiation is:
Electromagnetic Energy
Which of the following are examples of particulate radiation?
Alpha
Beta
The rate of the rise and fall or how often:
Frequency
The distance between two coressponding points:
Wavelength
At 60 kv; ______ wavelength, _____ frequency
Longer, lower
At 90 kV, ______ wavelength; ______ frequency
Shorter, higher
Is there a difference in velocity in a 60 kEV photon and a 90 kEV photon?
No difference
Velocity is a constant factor
X-ray photons move:
At the speed of light or not at all
What is the speed of light?
186,000 miles/second
3 x 10^8 meters per second
What is the relationship between wavelength and frequency?
Inversely proportional
As wavelength increases frequency decreases
What is the relationship between wavelength and energy?
Inversely proportional
As wavelength increase energy decrease
What is the relationship between frequency and energy?
Directly proportional
Increase frequency increase energy
Which controls the quality kvp or mAs?
kVp
Which controls the energy? kVp or mAs
kVp
Which controls the penetrability?
kVp
mAs
kVp
Which controls the quantity?
mAs
The rate of exposure:
mAs
The intensity of exposure?
mAs
Patient dose is: mAs or kVp
mAs
What controls the wavelength?
kVp
A Radiographic examination is performed with 70 kV, 10 mAs and a patient receives a dose of 18 C/kG (mR) a new exposure is made with 25 mAs to increase receptor exposure. What new intensity is to be delivered?
I1= 18 C/kg
I2= x
mAs1= 10 mAs
mAs2= 25 mAs
I1/I2= mAs1/mAs2
With the use of filters:
Increase quality and decrease quantity
Half-Value Layer definition:
Thickness of an absorbing material required to reduce x-ray intensity by one-half its original value
The amount of material necessary to reduce the intensity by 1/2 of its original value:
HVL
Half Value Layer
List the technical factors that affect HVL:
kVp
Filtration
The intensity is inversely proportional to the square of the distance
Inverse Square Law
If distance ever gets doubled or cut in half the intensity always gets changed:
By a factor of 4
4xs more
4xs less
If the patient is lying down on the table and they are your source of scatter if you are standing 40 inches away from the patient (100cm) your dose is 20 C/kg. 100 cm to 200 cm?
50 c/kg
A Radiographic examination is performed 80 kV, 20 mAs, 100 cm SID and the patient receives a dose of 15 C/kg. A new exposure is made with a 200 cm SID to reduce magnification. What is my new exposure/intensity/dose?
I1/I2 (D2/D1)^2
A Radiographic examination is performed with 80 kV 20 mAs with 100 cm SID. A new exposure is made with a 200 cm SID. What new technique can be used to maintain receptor exposure?
mAs1/mAs2 = (SID1/SID2)^2
Exposure Maintenance Formula
Direct Square Law
As useful radiation and consists of the x-ray photons directed through the x-ray tube’s window port in a direction toward the patient.
Pre-interaction (Primary Radiation)
The x-ray beam prior to the interaction with the patient:
Primary Radiation
Radiation that is emitted from atoms of matter after an x-ray photon from the primary beam interacts with matter (characteristic radiation)
Secondary Radiation
Also known as exit radiation
Remnant radiation
Image forming radiation
Remnant Radiation
Remnant radiation is also known as:
Exit radiation
A reduction in x-ray intensity as it passes through matter:
Attenuation
Fundamental properties of x-ray:
Power packed bundles of energy
Highly penetrating invisible rays that are a form of electromagnetic radiation
Herterogenous or polyenergetic (0 to peak 60)
X-rays travel in straight lines
Can ionize matter and release small amounts of energy upon passing through matter
Can produce chemical and biological changes
Produce secondary and scattered radiation
Travel at the speed of light 3 x 10^8 meters/second
No mass or electrical charge-not affected by electric or magnetic fields
A tech is exposed to 15 mGy/min for 7 minute flouro exam at 3 feet from the patient. What would the techs exposure be if he/she was 5 feet from the patient?
15 x 7 = 105 total exposure
105/x = 5^2/3^2
X= 37.8 Mgy
What would the exposure rate be at 5 feet?
15/x = 5^2/3^2
5.4 mGy/min
Where does the Compton interaction take place?
Outer shell electron
Partial absorption of the incident x-ray photon?
Compton
Who or what is your biggest source of scatter?
The patient
At what angle as your standing in the room at a flouroscopic situation, what angle would you receive the least amount of radiation as a technologist?
90 degree angle
Right angle
Perpendicular to the source
What is the maximum number of times an x-ray photon can be scattered before it loses all of its energy?
Twice (tube ounce theory)
Everytime an x-ray photon gets scattered it will leave with how much of its original intensity?
1/1000
.001
.1 %
One incoming, two leaving:
Compton
What photon will always have a longer wavelength in the Compton interaction?
Scattered photon because it is leaving with less energy that’s why it got deflected laterally
Which interaction is more prevelant? Compton or photoelectric?
Compton
The electron that you knock out on the edge of the Compton interaction is called:
Recoil or secondary electron
Incident photon interacts with an innermost shell electron of a target atom and removes an electron
Photoelectric
All of the remaining energy of an incident photon is transferred to the the ejected electron this is called:
Photoelectron
Which of the following is responsible of the patient dose effect?
Photoelectric effect
An incident photon interacts with an orbital shell electron, no ionization take place and no energy has been given up:
Coherent effect (classical)
An incident photon interacts with an orbital shell electron, no ionization take place and no energy has been given up:
Coherent effect (classical)
An incident photon interacts with an orbital shell electron, no ionization take place and no energy has been given up:
Coherent effect (classical)
Happens at very low x-rays less than 10 kEV:
Coherent (classical)
1% of x-rats incident on the patient reach the IR:
Differential Absorption
Difference is x-ray interaction by various body tissue:
Differential Absorption
X-ray image is formed by those x-rays that undergo photoelectric absorption and those that are transmitted to the image receptor:
Differential Absorption
As thickness increases (mass density):
Attenuation increases
The probability of photoelectric and Compton interactions increases, decreased x-ray transmission
How tightly compacted at the atomic level
Atomic number
Do you have different amounts of scatter with 10 cm of air vs 10 cm of bone?
No effect
Same amount of scatter
An atomical part that measured 10 cm and 20 cm which one has more scatter?
20 cm
100 Rads = _____ Gy
1 Gy
100/100= 1 Gy
Traditional number and multiply by .01
The unit of absorbed dose?
Gray
The unit of absorbed dose equivalent?
Sievert
Sv
Measurement of the biological effectiveness of radiation?
SV
Dose equivalent
Used in radiation protection only- measurement of occupational exposure
SV
If the radiation monitor of a radiation worker records that the worker received 2 mGy of x-rays, 1 mGy of fast neutrons, and 1 mGy of alpha particles, what is the absorbed dose equivalent for this worker?
2(1) + 1 (10) + 1 (20) = 32 mSv*
The unit of exposure in air:
C/kg (mc/kg) (uc/kg) or AIR KERMA
1st, 2nd, 3rd trimester, what is the most sensitive?
1st
1st, 2nd, 3rd trimester, what is the least resistant?
1st
X-ray QF:
1
Gamma ray QF:
1
Beta Particles QF
1
Protons QF:
2
Fast neutrons QF:
10
Alpha particle QF:
20
There is no safe dose:
Non-threshold
Used to compare the risk of cancer based on different types of radiation and different types of tissues:
Effective dose (SV)
KERMA stands for:
Kinetic energy released per unit mass
1 gy=
1 J/kg
Measures the ENERGY of ionizations in air:
AIR KERMA
Is the study of methods of interaction and the effects of ionizing radiation on living systems
Radiobiology
Some amount of radiaiton is required before a measurable effect can be detected
Threshold
Any given dose of radiation will yield some measurable effect
Non-threshold
Which number defines itself to be non-linear threshold? On the graph
3
Which number on the graph defines x-ray?
1 linear non-threshold
Cell division
Mitotic Activity
The more immature cell=
The more sensitive
Nerve and muscle cells:
Less sensitive
More radio resistant
What is the single most radio sensitive cell of the body?
Lymphocyte
Stem
Cell
Lymphocyte
Muscle
Nerve
List in order from least sensitive to greatest
Nerve
Muscle
Stem cells (intestinal crypt)
Lymphocyte
Stem
Cell
Lymphocyte
Muscle
Nerve
List in order from most sensitive to least sensitive
Lympcyte
Stem Cell (intestinal crypt)
Muscle
Nerve
Rate of energy deposited per unit track length through an absorber:
Linear energy transfer
Amount of radiation that is transferred to the body as the X-ray beam travels through the body
Linear Energy Transfer (LET)
What is the relationship between LET and RBE?
Directly proportional
Ability to produce biological damage
RBE
Diagnostic x-rays are considered: _____ LET radiaiton and _____ RBE
LOW, LOW
Defines the ability of aerobic conditions to enhance the effectiveness of radiation
Oxygen Effect
Which is more lethal
LD 50/30
LD 50/60
LD50/30
LD50/
Lethal dose of 50% of the population over a ____ number of days.
Equal doses of radiation that are delivered with time interval separations (time between exposures)
Fractionation
Radiation dose that is delivered continuously but at a loaner dose rate:
Protraction
Offers a cell the greatest ability to survive and recover from radiation exposure
Fractionation
Radiation interaction with water
Radiolysis
Radiation is:
Indirect interaction of biological damage
Free radicals can combine to form toxic substances such as:
Hydrogen peroxide
-OH* + OH = H2O2
Positive water molecule can split into a:
Free radical highly reactive and unstable substance
If what phases is the cell considered to be the most radiosensitive?
Metaphase
M-phase
During the cell division process
Cell division
Mitosis
Germ cell division
Miosis or meosis
What is a germ cell?
Sex cell
Reproductive cell
Mitotic activity resumes after a
Short delay
1 rad
1 Gy
.01 mGy
Is Mitotic delay considered to be a threshold or non threshold dose response?
Can occur at :01 gy or 10 mGy
Threshold!
Mitotic delay can occur at:
.01 Gy or 10 mGy
Reproductive failure can occur as little as:
1-10 Gy
Cell goes through one or more Mitotic phases and then dies
Mitotic (genetic) death
Phases of cell division in order
Prophase
Metaphase
Anaphase
Telophase
Master molecule or target molecule
Target
Somatic effect (changes)
Effect individual cell of the body
Cancer
A high radiation dose delivered to the long bones of the lower extremities that results in a suppression of the of the hemopoietic system and causes loss in the volume of circulating red blood cells in the body
General somatic effects