Safety Flashcards
(228 cards)
1
Q
X-ray production requires 4 things
A
- Thermoinc emission
- Acceleration of electrons
- Focusing of electrons
- Deceleration of electrons
2
Q
Heating of the filament to the point that electrons boil off its surface
4-6 amps of current
Ma settings determine the amount of current that will be sent to the filament
A
Thermionic emission
3
Q
Cathode filament wire is made of?
A
Thoriated tungesten
4
Q
Target is made of
A
Tungsten with rhenium alloy
5
Q
High electrical potential applied to the cathode end of the x-ray tube
X-Radiation if produced as a result of high speed electrons bombarding the target area of anode
A
Acceleration of electrons
6
Q
Unit of electric potential is?
A
Volt or voltage
7
Q
Surrounds the filament and maintains a concentrated stream of electrons from the filament to the target area on the anode
Made of molybdenum nickel OR millennium alloy nickel
A
Focusing cup
8
Q
What two components make up the cathode
A
Filament wire and focusing cup
9
Q
*High speed electrons strike the tungsten target on the anode
This interaction results in primarily the process production of heat (99% is heat/thermal energy) *
A
Deceleration of electrons
10
Q
Current for thermoinc emission is a
A
Step down transformer
11
Q
Smallest subdivision of an element that maintains all the physical and chemical properties of the element
A
Atom
12
Q
Theory that is described as a tiny solar system costing of:
- nucleus (central core) containing positively charged protons and electrically natural neutrons
A
Niels bohr theory
13
Q
Protons and neutrons have an atomic mass equal to?
A
1
14
Q
Equals the number or protons in the nucleus
A
Atomic number (z#)
15
Q
Equals the sum of the protons and neutrons in the nucleus
A
Atomic mass (a#)
16
Q
Protons and neutrons equal the number of?
A
Nucleons
17
Q
Atom with the same atomic number as the element but with different atomic mass
A
Isotope
18
Q
negatively charged particles located in discretely organized orbital shells outside the nucleus and contain virtually no mass
1st orbital shell is known as the k.shell, 2nd is L shell, 3rd is M and so on..
A
Electrons
19
Q
Electrons are held in their orbital shell by there?
A
Binding energy
20
Q
Binding energy depends on
A
Location of the election (closer is stronger)
Complexity of the atom (higher atomic number = stronger)
21
Q
The number of electrons in the last orbital shell
A
Valance number
22
Q
Valance number formula
A
2n^2
K-8
L-8
M-18
N-32
O-50
P-8
23
Q
Occurs when an energy source contains sufficient energy to remove an electron from one of the orbital shells
Previously uncharged atom will now have an electron charge
A
Ionization
24
Q
Projectile (high speed) electron intervals with the electrostatic charge of the target (tungsten) nucleus
Projectile electron under 3 processes
1. Slows down
2. Changes direction
3. Loses some of its energy
A
Bremsstrahlung radiation (breaking radiation)
25
90% of all x-ray production
-100 % below 70 kvp
Bremsstrahlung radiation
26
The more extreme the direction change = stronger photon
Bremsstrahlung radiation
27
Projectile (high speed) electron interacts with a tungsten target atom by ejecting a inner shell electron and ionizeing the atom
- k shell vacant is filled by an outer shell electron
- the electron may be from L,M,N,O,P orbital shells of tungsten atom
- results in emission of chacterietic x-ray photon
Characteristic radiation
28
***Energy of the x-ray photon is equal to the difference between the electron binding energies of the orbital shell that contained the vacancy (k shell) and orbital shells that filed the vacancy
Chacterietic radiation
29
Only k shell x-rays (those chacterietic x-rays that are produced as a result of a k shell vacancy) are _______
Diagnostically useful
30
Kvp needs to be ____ or higher to eject a j shell electron
70
31
When producing k chacterietic radiation must have a tube potential of at least
70
32
X-Radiation is one form of _________ _________of the electromagnetic spectrum
Electromagnetic energy
33
The smallest bit of electromagnetic energy is called a
Photon or quantum
34
Other forms of radiation such as best and alpha radiation, travel in particles is called
Particulate radiation
35
Is the rate of rise and fall (oscillation) of electromagnetic photon and is measured in the unit hertz (hz)
Frequency
36
Is the distance between two successive peaks of an electromagnetic photon
Wavelength
37
Frequency and wave length are _______ related
Inversely
X-Radiation has high frequency and short wavelength
38
As the frequency of electromagnetic radiation increases, __________ decrease
Wavelength
39
Moves at
186,000 miles/sec
40
The energy level of the x-ray beam
Increase in KVP results in a increase in x-ray _____
Quality and beam penetrability
Kvp is filtration
41
Express the intently or amount of X-rays in the beam
Influenced by mas
Quantity
42
Is inversely proportional to the square or the distance from the radiation source
- the inverse square law is used to calculate a change in beam intensity with change in sid
Distance
43
I1 sid2 ^ 2
=
I2. Sid1 ^2
When intensity is used in, use this formula
Inverse square law
44
Used to maintain the radiographic density (receptor exposure) with change in sid
MAINTAIN
Direct square law
45
46
***
Mas1. Sid1 ^2
=
Mas2. Sid2 ^2
Direct square law formula
47
Also known as useful radiation
Consists of the x-ray photon directed through the x-ray tubes window port in direction towards the pt
Primary radiation
48
49
The beams primary interaction with the patient is
Primary radiation
50
X-ray phtons in the primary beam are known as
Incident photons
51
Radiation that is emitted from atoms of matter after an X-ray photon is the primary beam interacts with matter (characteristic radiation)
Secondary radiation
52
Known as exit radiation
The portion of the attenuated x-ray beam that emerges from the patient and interacts with the image receptor
- known as the image forming beam
Remnant radiation
53
Defined as progressive absorption of the x-ray beam as it passes through matter
Attenuation
54
Attention is the sum of what
Absorption and scatter
55
X-rays are packets of energy that travel in
Wave form
56
X-rays are Highly penetrating, invisible tags that are a form of
Electromagnetic radiation
57
X-rays are heterogenous and poly energetic, meaning:
Have a wide variety of wavelength and energies
58
X-rays travel in
Straight lines
59
X-rays travel at the speed of?
Light , 3.0 x 10^8 m/sec
60
X-rays Can ionize matter and release
Small amounts of energy upon passing through matter
61
Through ionization and excitation of atoms and molecules, x-rays can produce
Chemical and biological changes in matter
62
X-rays have very high _____ and very short ______ and interact with matter on a atomic and molecular level
High frequency
Short wave length
63
64
Partial absorption of the incident x-ray photon
The incident x-ray photon (primary beam photon) INTERACTS WITH A OUTER SHELL electron of a target atom and REMOVES AN ELECTRON
Compton
65
What is the most common interaction
Compton
66
Source of most exposure and dog in ir
Compton
67
Attenuation is effected by
Thickness and atomic number
68
Results in degradation of image contrast, side scatter, resulting in OCCUPATIONAL EXPOSURE or back scatter, resulting in patient exposure
Compton
69
Compton interaction is influenced by the
Energy of the x-ray beam and thickness of tissue irradiated
70
Total absorption of the x-ray photon
Incident x-ray photon INTERACTS with inner (k) shell electron of a target atom and REMOVES electron
Photoelectric
71
All of the remaining energy of the incident photons is transferred to the electron is called
Photoelectron
72
Is the PRIMARY source of PATIENT radiation exposure
Photoelectric
73
What is responsible for biologic effect pt dose or rate/intensity
Photoelectric absorption
74
Ei= eke + eb
Photoelectric effect equation
75
Releases the secondary radiation with outer shell move into stabilize electron
Increase pt dose
Photoelectric
76
Also known as classical, coherent, or Thompson
- Incident x-ray photon interacts with a target atom and excites the atom
-No orbital electrons are rejected, no ionization takes place
- No energy is exchanged between the incident photons and then target atom
- indicent x-ray photon undergoes change in direction with NO ENERGY LOSS
Coherent (classical) - unmodified scatter
77
Unit of absorbed dose
Determines the amount of energy from the x-ray beam that is transferred to the absorbing object
Standards until of equivalent
Gray
78
1 gy = ___ rads
100
79
Unit of absorbed dose equivalent
Standard international unit equivalent is the sievert
Dose equivalent
80
1 sv = ____ rems
100
81
Defines the unit of radiation exposure that will yield 2.58 x 10^-4 columbs per kilogram of air
Exposure c/kg
82
Unit of measurement of radioactivity
Curie (ci)
83
International standard equivalent is the
Becaurel (bq)
84
Equivalent dose x wr x wt
Expressed in sv or msv
Efd formula
85
Any given dose of radiation will yield some measurable effect
Probability increases as dose increases
Non threshold dose effect relationship
86
Same amount of radiation is required before an immeasurable effect can be detected
Ex: leukemia
Threshold dose affect relationships
87
Skin erythema occurs at a skin dose of
2 gray
88
Constant slope
- an observed response IS DIRECTLY PROPORTIONAL TO DOSE
Linear
89
At some point the slope of the dose response curve varies
NOT DIRECTLY PROPORTIONAL TO THE DOSE
curvilinear
90
Constant varying slope of the dose response
S shaped
Sigmoidal
91
Cell radiosentivety is affected by
Mitotic activity
Maturity
Degree of specificity
92
Radiosentivety is increases with increased mitotic activity
Direct
Mitotic activity
93
Radiosentivety decreases with increased maturity
Stem cells (less mature) and more radiosentive than nerve cells (very mature)
Maturity
94
Radiosentivety decreases with increased specificity (specialization)
Stem cells (less specific) are more radiosentive then nerve cells (more specific)
Degree of specificity
95
Defines the rate of energy deposited per unit track length through an absorber
Amount of radiation that is transferred to the body as the x-ray beam travels though the body
Let
96
Let us GREATEST FOR _____ and LOWEST for _&&_
Alpha particles
X-ray and gamma radiation
97
Lymphocyte
Stem cell
Muscle
Nerve
Most to least sensitive
98
Increasing oxygenation to the cell increases CELL SENSITIVITY to radiation
Oer for human tissue has a maximum of approximately 3.0
Tissue is more sensitive in oxygen sate
Oxygen effect (oxygen enhancement ratio)
99
Defines the ability to produce biological damage
Diagnostic X-rays are considered low let traditional
Rbe
100
**Increasing the let of radiation will result in an increase in biologic damage
- let and rbe are DIRECTLY related
Rbe
101
102
As let increases cell survival and recovery _____
Decreases
103
Equal doses that are delivered continuously but at a lower dose rate
Fractionation
104
Radiation dose that is filtered continuously but at a lower dose rate
Protraction
105
As a cells oxygen level increases the cells sensitivity to radiation ____, and survival _____
Increases
Decreases
106
*Radiation interaction with water
Radiolysis
107
Photon water interaction results in ionization of water
Hoh+ and e-
108
Positive water molecules can split into a ____- highly reactive and unstable substance
Free radial
109
*free radicals can combine to form toxic substances such as
Hydrogen peroxide
110
OH* + OH* = H2O2
hydrogen peroxide
111
Radiation is INDIRECTLY the cause of
Biological damage
112
Radiation damage to the body is
s caused by the indirect action of
Radiation interacting with water
113
Also known as apoptosis
Interphase death
114
Metaphase is the most
Sensitive
115
Cell dies without attempting to divide
Amount of radiation to chase interphase death depends on the radiosensitivity of the cell
During interphase death
116
Chromosomes line up
Prophase
117
Chromosomes line up at the equator
Metaphase
118
Sister chromatids pull apart
Anaphase
119
Cell pinches in the middle
Telophase and cytokinesis
120
Cell goes through one or more mitotic phases and then dies
Mitotic, genetic death
121
Can be caused by as little as 1 rad (absorbed dose) (.01 gy or 10 mgy)
Mitotic delay
122
Cell does not die as a result of radiation exposure but LOSES THE ABILITY TO PROCREATE
100 to 1000 rads (1-10 gy)
Reproductive failure
123
Temporary or permanent interruption of cellular function
If repair enzymes fix the damage, the cell can recover and resume normal function
Interference of function
124
Effects are those that are limited to the exposed population
Somatic effects
125
Those that occur relatively soon after exposure, seconds, minutes, hours, days, weeks (within first 6 months)
Short term somatic effects
126
Epilation, nausea, vomiting, erythema, fatigue, epistaxis
Short stern somatic effects
127
Effects are those that occur years after exposure (6 months after exposure)
Long term somatic effects
128
Cancer (leukemia) cataractogenisis, and life span shorting
Long term somatic effects
129
Large doses delivered over a short period of time
- results in a greater life span shortening than chronic radiation exposure
More harmful then chronic
Acute (short term exposure)
130
Radiation delivered in small increments over a long period of time
*1 rad (.01 gy or 10 mgy)= 10 days of life span shortening
Chronic long term exposure
131
What part of the eye is the most radiosensitive
Lens
132
Cataractogenisis
Occurs on posterior pols of the lense
Eye
133
Follows a nonlinear, threshold dose (stochastic) response relationship
Cataractogenisis
134
Follows a linear, non threshold dose (stochastic) response relationship
Thyroid
135
Follows a linear, non threshold dose (stochastic) response relationship
Breast
136
Destruction of bone marrow, reduction in RBC, WBC, and platelets
Bone marrow
137
Follows a linear threshold dose
Bone marrow
138
Reddening of skin
Erythema
139
Sloughing off of skin cells
Desquamation
140
Hair loss
Epilation or alopecia
141
Follows a threshold non stochastic dose response relationship
Skin
142
Immature ova are very radiosensitivity
Temporal sterility - 2 gym
Permeant- 5gy
Female gonads
143
Will depressed the sperm population
Permeant-5-6 gy (5000-6000 mgy)
Doses of 10 rada (.1 mgy) can result in genetic mutation
Male sperm count
144
First trimester is the most
Radiosentive (bc more stem cells)
145
The trimester of exposure plays a key role in determining the
Risks
146
very sensitive
Neuroblast formation
Doses ranging 20-40 rads (.2-.4 gy) (200-400mgy) can cause microencephlay
Cns
147
Long term somatic effects
Limited to the exposed individual and area of exposure only
Local somatic effects
148
Effects that are limited to the exposed individual but the response to the radiation effects the entire body
General somatic effects
149
These are all or nothing effects- non threshold
RANDOM
Stochastic (probalistic) effects
150
Exhibit the existence of a threshold (effect not observed with low doses)
Typically occur at higher radiation doses
Biologic effects increase in frequency and magnitude with increased in radiation dose
Cataracts, erythema, fibrosis, hematopoiesis damage
Non stochastic (determitic) effects
Tissue reactions
151
Cns is sensitive in first trimester
0.2-0.4 gym can cause?
Microcephaly
152
Radiation exposure to female pts within child bearing age should be limited to a period of time within 10 days following the onset of menstruation
Ten day rule
153
The fixed number of reproductive egg cells available to exposure at birth
Biological effects
154
Spermatogonus cells are constant reproduction throughout a males life time
Special concerns for the male pt
155
Pedis are ___ more sensitive
5 x
156
Pediatric cells reproduce frequently making them for radiosentive
Pedis have longer life expectancy which gives them long term somatic effects
Have a larger percentage of their body exposure to radiation
Pedis
157
Exams that require a considerate amount of radiation (long exposure time) are high risk exams for Pedi pts
High risk exams
158
Acute radiation syndrome is known as
Hemopoietic syndrome
159
Also known as bone marrow syndrome
Exposure doses ranging between 100-1000 rads (1-10 gy) to whole body
May result in depressing the body's immune system and blood clotting ability
Death occurs between 3-6 weeks
Hemopoietic system is the most radiosensitive
Hemopoietic syndrome
160
Requires dose between 1000-5000 (10-50 gy)
Symptoms are nausea, vomiting fatigue
Death occurs approx one week following exposure
Gi syndrome
161
Can be called cardiovascular syndrome
Occurs with exposure over 5,000 rads (50 gy)
Death occurs within hours or days
Cns
162
As complexity increases, threshold increases, and survival decreases
Acute radiation syndrome
163
Effective on skin and organ exposure
Removed low energy, non diagnostic x-ray photons
Increases effective energy and quality
Filtration increases exposure decreased
Filtration
164
Total filtration is made up as
Inherent and added
165
Minimum requirement of of 70 kvp or more for filtration
Ncrp report 102
166
Below 50 KVP requires
0.5 mm aluminum
167
50-70 kvp
1.5 mm aluminum
168
70 kvp or above
2.5 mm aluminum
169
Inhernt filtration ranges between
0.5 and 1.0 mm
170
Helps reuse the need for repeat radiographs due to pt motion or lack of pt cooperation/anxiety
Pt communication
171
Has a larger exposure latitude compared to film screen
Elimates retakes due to overexposure up to 500% and underexposure up to 80%
Digital imaging
172
Collimation
Reduce mag
Due to the small size pedis have more of their body in the path of the central ray
Pedi dose reduction
173
As low as responsibly achievable
Alara
174
Use requires more exposure then images without
Will significantly improve radiographic contrast
The general rule is 10-13 cm
Grids
175
Alternative to grid use
Requires use of a long SID combo with a increased OID
Does not result in a decrease in production of secondary or scattered radiation
Results in a reduction in their effect due to a high percentage of secondary and scattered radiation diverting away from the ir
Air gap technique
176
Digital form of fluro
Decreases pt exposure, x-ray beam is turned off while the image is being scanned
Last image hold
Pulsed fluro
177
Stores the image from the last time the fluro switch was depressed
Last image hold
178
Increased KVP and lower ma
Reduces pt dose
179
Entrance exposure is greater then exit exposure
Positioning
180
Length of fluro exam must be modified by a 5 MIN CUMULATIVE TIMER
300 sec
Fluro
181
Sometimes is necessary on Pedi or Geri pts
Helps decrease fluro time and the need for repeat radiographs due to pt motion
Immobilization
182
Photoelectrons are accelerated to the output phosphur from the entire input phosphor
25 cm mode
183
Voltage increases on the electrostatic lense causing the electron focal point to move further away from the output phosphor
17 cm mode
184
Minimum source to distance for fluro units
15 inches (38 cm)
185
Mobile units source to skin distance
12 inches (30 cm)
186
Minimum distance for mobile xray
6 foot exposure cord (72 Inches 180 cm)
187
Any radiation dose carries with it some biological risk
Medical imaging principal of radiation protection is based on the non threshold linear dose response relationship
Ethical responsibility to minimize pt. dose
188
Radon
Cosmic
Terrestrial
82% of avg. Annual exposure to ionizing radiation
Natural sources
189
Medical imaging procedures are the greatest source
Artificial sources
190
Time, distance, shielding
Which Is most effective
Which is most common
Distance
Shielding
191
192
Lead aprons mm pb?
0.5 required
193
Gloves
0.25 mm pb
194
Thyroid shield
0.5 mm pb required
195
Glasses
0.35 mm pb
196
Buckley slot and protective curtain
0.25 mm pb
197
Clear lead plastic over head protective barrier
0.5 mm pb
198
For mobile shielding mm pb requiring
0.25 mm pb
199
Located perpendicular to the primary beam
Require 1/16th (.16 cm or 1.6 mm) of pb equivlent
If the primary barrier is a wall, the lead needs to be extended 7 feet up from the floor
Primary barriers
200
Surfaces struck with stray radiation (leakage and scatter)
Parallel to the primary beam
1/32 inches of pb equivlent
1/2 inch of the second barrier must overlap the primary barrier
Secondary protective barrier
201
0.25 mm or 0.5 mm pb is preferred
Protective straps and protective bucky slot covers
202
How much time the barrier is exposed to radiation
Use factor
203
Must yield an audible signal and interrupt the floyroscopuc beam after a period of 5 minutes of fluro
Cumulative timer
204
Typical conventional (non dig) fluro units operate within a range of
2-5 ma
205
Fluoroscopic exposure switch should be
Dead man type
206
___________ if the worker can potentially be exposed to 25% of the annual total effective dose equivalent limit
Determines occupational exposure
207
Occupation exposure records must be kept as long as the
Worker is employed in medical imaging
208
Reveals whole body exposure, deep and shallow dose equivalent, and lens of dose equivalent
Records monthly, quarterly, yearly, and lifetime exposure
Letter m indicated motions device recorded and equivalent dose below the minimum measurable radiation quality
Content
209
*Utilizes an aluminum oxide detector
Laser light reads the sensing material (emit light in proportion to exposure )
Filters made of aluminum, time, and copper allow for determination of the energy levels sticking the badge
Osl
210
Pocket
Osl
Tld
Film badge
Most to least sensitive
211
Immediate reading
The ability of ionizing radiation to ionize gas within a sealed chamber resulting in a change of charged electrode- discharging the electrode
Pocket dosimeter
212
* Functional component is lithium fluoride.
Made by heating the lithium fluoride chip to the point of combustion.
The light spectrum of the chip will change with changing levels of energy absorbed by the chip (thermoluminescence).
Good for monitoring over a long period of time.
No archival record other than a written record.
Tld
213
Contains a small piece of radiographic film
Relies on the ability of ionizing radiation to effect the density change on the film emulsion.
Amount of dose received by the badge is a function of the degree of film blacking that takes place on film emulsion
Are effective for radiation monitoring over an extended period of time
Provides a permeant record
Film badge
214
215
Monitoring devices should be worn
Outside lead aprons
216
One for the collar, and one for measuring radiation delivered to the abdomen
Pregnant tech
217
For a present tech, the abdomen badge is worn
Under the lead apron
218
Embryo dose limits
Entire period:
Month:
0.5 rem (5msv)
0.05 rem (.5 msv)
219
Used to monitor installation of diagnostic radiographic machines
Measures fluroscooic scatter rates
Exposure rates of pts contain therapeutic doses of radiation material
Exposure rates for radioisotope storage facilities
Cumulative exposure outside protective barrier
Gas ionization chamber instrument
220
Ncrp #116
Annual whole body exposure
50 msv
5 rem or 0.05 sv
221
Ncrp #116
Lense of eye
150 msv
15 rem
0.15 sv
222
223
Ncrp #116
Skin extremity, all other areas
500 msv
50 rem
0.5 sv
224
Ncrp #116
General population
5 msv
225
Control badge reading should be
0 (if higher it means it's exposured in transit)
226
Ncrp #116
Annual effective dose equivalent limit
5 msv
0.5 tem
227
228
Ncrp #116
Dose equivalent limits for lens of eye, skin, extremities
50 msv
5 rem
