Lecture 9- Radiation Safety Flashcards
1
Q
what is the biggest source of radiation to the US momulation
A
radon or medical imaging
2
Q
what is the biggest source of radiation to the US momulation
A
radon or medical imaging
3
Q
what is the difference between Denver and New ORleans
A
Denver has more radiation
4
Q
what is the typical annual radiation to a human
A
.2mSV
5
Q
what is cosmic radiation
A
cosmic ray particles originate from outside the solar system and from solar flares. When striking the earths upper atmosphere, particles are defected by van Allen belts. Radiation at Earths surface includes primary ET radiation secondary radiation showers which are particles from the upper atmosphere having collisions
6
Q
does radiation decrease with elevation
A
no it doubles every 5000 feet
7
Q
is exposure higher with air travel
A
yes, and frequent fliers
8
Q
how much extra radiation do airline crews and frequent fliers recieve
A
1mSv annullay
9
Q
is radiation higher at equator or poles
A
it is higher at the poles
10
Q
what is the dose percent decrease between indoor and outdoor
A
indoor is 20% less than outside
11
Q
what is terrestrial radiation
A
radioactive things in the soli and primordial radionucelotides. Radioactive atoms with half-lives comparable to the age of the earth.
12
Q
what primordial radio nucleotides are most radioactive
A
K-40 and uranium 238 and thorium 232
13
Q
what is beta radiation
A
it is electrons like aluminum foil
14
Q
what is beta radiation
A
it is electrons like aluminum foil
15
Q
what is the difference between Denver and New ORleans
A
Denver has more radiation
16
Q
what is the typical annual radiation to a human
A
.2mSV
17
Q
what is cosmic radiation
A
cosmic ray particles originate from outside the solar system and from solar flares. When striking the earths upper atmosphere, particles are defected by van Allen belts. Radiation at Earths surface includes primary ET radiation secondary radiation showers which are particles from the upper atmosphere having collisions
18
Q
does radiation decrease with elevation
A
no it doubles every 5000 feet
19
Q
is exposure higher with air travel
A
yes, and frequent fliers
20
Q
how much extra radiation do airline crews and frequent fliers recieve
A
1mSv annullay
21
Q
is radiation higher at equator or poles
A
it is higher at the poles
22
Q
what is the dose percent decrease between indoor and outdoor
A
indoor is 20% less than outside
23
Q
what is terrestrial radiation
A
radioactive things in the soli and primordial radionucelotides. Radioactive atoms with half-lives comparable to the age of the earth.
24
Q
what primordial radio nucleotides are most radioactive
A
K-40 and uranium 238 and thorium 232
25
what is alpha radiation
helium nun which is lungs
26
what is beta radiation
it is electrons like aluminum foil
27
hw does the radiation from the terrrestrial sources get into the body
into the lungs because partcles are inhaled from the soil
28
how does radon usually get into the body and what kind of radiation is it
alpha radiatin and it is breathed in
29
what is the largest background source of radiation
radon
30
what is radon from and the half life
it is from uranium 238 and it is from alpha decay with a half life of 3.8 days
31
what building feature is important for radon exposure
ventilation is important
32
what unit are radon levels measured
it is measured through picoCuries per Liter
33
what is the disadvantages to film badge
requires processing and no direct readout, and excessive moisture and heat may damage the film
34
what is the primary internal radiation and where is it found
muscle and pottasium-40
35
what are the highest source of artificial radiation
medical exposures and mostly diagnostic xrays
36
what causes cigarettes to be radioactive
they have polonium
37
what is the dose from cigarettes
it is usually 16- mSV to bronchial epithelium and 13 mSV effective dose. More than a CT
38
what occupation has the highest occupational exposure and how does that compare to people working in radiology
uranium miners have 12 mSV as dose and radiologists and radiology techs are 1-.7
39
what is the typical dose for a an interventional radiologist and cardiac cath lab staff
it is 18 and 5
40
where do you wear a personal dosimeter
front torso when no apron or collar with apron
41
what are the three main types of peronnel dosimeters
film badges, storage phosphor dosimeters, pocket dosimeters
42
how does a film badge work
radiation darkens the film proportional to the dose. Energy of radiation is determined by including metal filters in front of part of the film.
43
what does the report include for film badges
a shallow does (skin dose) and beta radiation. It has a deep dose which is penetrating radiation and includes X-ray
44
what are the advantages of a film badge
wide recorded exposure range, durable and rugged, permanent record, and economical
45
what is the range for x-rays and beta radiation of a film badge
xray is 100uSV-15SV
| beta radiation- 500uSV-10SV
46
what is the disadvantages to film badge
requires processing and no direct readout, and excessive moisture and heat may damage the film
47
what are storage phosphor dosimeteres
includse a material that traps radiation even in excited energy state. Some storage process with trap plus record event and event changing electronstrugcture energy is given off proportional todos record
48
what materials are used
TLD- lithium fluoride, and OSL which is aluminum oxide activated with carbon. Both types are configured with filters for radiation energy determination
49
what is the advantage to storage phosphor dosimeters
wide recorded energy range and can be reused. It is 10uSV to 10SV
50
what is the disadvantage to storage phosphor dosimeters
requires processing-no direct readout, destructive readout for TLD and OSL can be verified by repeating a few times. higher cost than film
51
what is a pocket dosimeter
used for high exposure situations.
52
what are the types of pocket dosimeters
G-M tubes, radiation, ion chamber, sensitive diodes
53
what is the main region for the gas filled detector
it is the geiger muller region draw it and it is the cascade of events happen
54
what are the disadvantages
initial cost
55
make a summary chart for these
see slide on the 11 page
56
how does gas-filled detector work
gas is ionized by radiation ions are collected and converted to signal. Incoming radiation ionizes the gas and converted to electrical signal
57
how does a scintillator work
there is emission of light from radiation interactions
58
how does a semi-conductor reactor work
they are semi-conductor crystals of Silcon or geranium with impurities so they act as a diode and allows current flow after a radiation interaction
59
what are the types of detector in terms of usage
counters, spectrometers, dosimeters
60
what is a counter detector
determines the number of radiation interactions
61
what are spectrometers
they determine the energy distribution or spectra of radiation
62
what are dosimeters in terms of use
determine total energy deposited by many interactions
63
how does a gas filled detector work
two electrons with voltage applied and radiation forms ion pairs with gas and this charge is collected by electrodes and is calibrated by meter
64
what is an example of ionization chamber
nuclear medicine survey meter, and x-ray exposure meter
65
what are the issues with the amount of electrical charge felt by gas-filled detectors
gas filled are different based on electrical charge carried. IF there is not enough voltage then there is too little. Want to hit the proportional region where single is determinedly voltage but area lower were radiation is only factor.
66
what is the main region for the gas filled detector
it is the geiger muller region draw it and it is the cascade of events happen
67
what does the detector absorption of radiation depend on
photon energy
detector atomic number
detector density
detector thickness
68
describe a scintillation detector
it emits UV or visible light after interaction. Interaction raises electrons to excited energy level, light emitted when electrons fall back to lower energy level.
69
what is the difference between phosphorescence and flourescence
fluoro is prompt emission
| phosphorescence- delayed emission
70
what are trapped electron scintillarotsi
after interaction, electrons remain trapped in excited state until heated or scanned with laser. Thermoluminescent dosimeters- used for personnel Photostimulabel phosphorus used as imaging plates for computed radiography
71
what are modes of detector operation
current mode which individual interactions are averaged together. Pulse mode each interaction is processed individually. Dead time can be problematic. 2 interactions must be separated by a finite time interval to produce distinct signals. iF a second interaction occurs during the dead time interval following another interaction, it is not counted and may disrupt the operation of the detector
72
what is dead time for non-paralyzable
it is high interaction rates and detector resprtss an underestimated signal
73
what is dead time for paralyzable
it is a high interaction rates, detector reports that no radiation is present
74
detection efficiency is measured by
number detected/number emitted or efficiency= geometric efficiency times intrinstic efficiency
75
what is geometric efficiency
fraction of photons emitted that reach the detector
76
what is intrinsic efficiency
fraction of photons reaching the detector that are absorbed
77
what is geometric efficiency dependent on
it is dependent on size of detector, shape and proximity to the source of radiation
78
what is the best for increasing geometric efficiency
it is best if it is in a well, so if it is put in a box it is best
79
what is intrinsic efficiency
it depends on how well the detector absorbs radiation, which is a factor of photon energy, detector atomic number, detector density and detector thickness
80
what does radiation protection and control depend on
time, distance, shielding
81
how do you minimize time
minimize the fluoroscopy on time and image acquisition. Exposure should not be activated if unprotected individuals are in the procedure room. Leave the procure room during exposure when possible, particularly image acquisition
82
how do you control for distance
radiation source is like a point at the center of a sphere. Exposure is determined by the inverse square law
83
what is the formula for the inverse square law
it is E2=E1(D1/D2)squared
84
what can you do to help with shielding
material absorebs radiation abd best protection is by distance and shielding.
85
what are the two types of shields
structural and personnel protection devic
86
what do we do for CT rooms for structural shields
consider scatter and leakage only, primary beam is always intercepted
87
what must the exposure no exceed for adjacent to x-ray rooms
50mSV for occupational workings, 1mSVper year for pibic or 20mSV in any hour for for other personnel or public
88
what is the primary radiation
it is the useful beam
89
what is the scatter radiation
it is the exposure rate for generally .1% and primary form patient to a 20x20 field size increases with field size
90
what is the leakage radiation
xray is not in primary beam
91
what are the design parameters
workload, use factor, occupancy factor, distance,
92
what is the workload for shield
amount of X-rays produced
93
what is the use factor for shield
fraction of time the radiation source is directed at specific surface
94
what is the occupancy factor for shield
fraction of time someone occupies an adjacent area
95
what is the distance for shield
from source to a specific surgace
96
what do we do for radiography and fluoroscopy rooms for structural shields
if walls are gypsum, generally added lead is required but concrete or brick may be used
97
what do we do for mammography rooms for structural shields
generally no lead is needed due to low X-ray energy an minimal scatter
98
what do we do for CT rooms for structural shields
consider scatter and leakage only, primary beam is always intercepted
99
what are lead gloves used for
they are used if the hangs are directly in the beam
100
what is used to protect the thyroid
it is thyroid held and it is used if there is high exposure
101
what is the mammography program under
MQSA
102
what is the lead with lead glasses
it is optional use in high exposure situations, and side shields are important, but they can be heavy
103
what can happen if the intervention radiologist doesn't protect themselves with eye wear
it can lead to cataracts
104
what are portable barriers and what are the specifications for it
it is transparent lead-acrylic plates which have .5-1mm lead equivalent. It is flor mounted or ceiling mountd or it can be on wheels. There can be lower body shelved for blocks and back scatter and tube leakage
105
what can increasing tube filtration do to help
increasing tube filtration minimum HVL of 2.3 mm AL at 80 KVP required added filtration decreases the skin dose
106
what does colimating to the body part do
it can reduce dose to areas outside the primary beam reduces scatter to improve image contrast
107
do you shield the patient or use shields only for personell
it can be used for the rest of the patient too
108
what should you do with source to patient distance
it should be increased to a certain dose so that patient is towards detector
109
what is the recommended screen film speed
fast speed image receptor screen-film: 400 speed recommended and CR is 200 speed
110
what should be implemented at the institution to prevent accidents
it is quality control to reduce errors
111
what does NRC stand for and what does it do
it is the US nuclear regulatory commission- rgulates the nuclear materials, and agreement states can carry out NRC regulation enforcement. Rules include persona exposure monitoring, and radioisotope control and disposal, and personnel training, reporting misadministration
112
what does the FDA do with this
it regulates radoopharmaceuticals and X-ray equipment maufacturers.
113
what is the mammography program under
MQSA
114
what is the dose limit to the whole body
50 mSV
115
what is the dose limit to the individual organ
500 mSV
116
what is the dose limit to the eye
150 mSV
117
what is the dose limit to the skin
500 mSV
118
what is an effective dose
it is a calculated quantity that reflects the radiation detriment of a non-uniform exposure in terms of a whole body exposure that would yield the same biological. Radiology takes in the radiation sensitivity
119
what is the dose limit to embyro
5 mSV
120
what is the dose limit to members of the public
1 mSV
121
what is ALARA
it is dose limites that are not meant to be indications of what is considered safe. Radiation protection doctrine is ALARA. Radiation exposure is to be kept as low as reasonably achievable
122
what does ALARA stand for
as low as reasonable achievable
123
what are patients where patient dose is nescessary
after exposure, a patient discovered that they are pregnant, and research protocols to include the exposure to ionizing radiation, and regulatory requirements for mammography, and estimated skin dose to avoid radiation burns, and general patient requests
124
what are the organ doses important
it is the dose absorbed by an organ, and energy imparted to organ/mass of organ, and it is used full for organ specific risk estimates/epidemiology, and unites are gray. typical are tends of grets
125
what is the effective dose used for
it is only for reference phantom. It is organ estimated to these reference phantoms however, the tissue weighting factors are for a reference population of both genders and all ages. It is tissue weighting is not specific to gender but is an average. It has organ doses for these two phantoms are combined to calculate E. While organ dose estimates can be calculated for any phantom model or vowel data set, E is defined only for a singular reference person. E is not defined for any other phantom or person
126
what is the equivalent dose
absorbed dose time radiation weighting factor
127
what are the units for equivalent dose
it is from gray to sievert
128
what is a radiation weighting factor
it is that there are different paths for each
129
what is the difference between effective dose and equivalent dose
absorbed dose is in the diagnostic and effective dose is different
130
what does the radiation weighting factor do
it rakes into account the type of radiation
131
what does into calculating the effective dose
organ estimates, tissue weighting factors, and this means that it is not a physical quantity
132
how are tissue weighting factors determined
it is for different tissues, the gonards, retinas and breast are more sensitive
133
what is the MIRD
it is the medical internal radiation dosimetry
134
what does MIRD do
it is the way that there is a 3D phantom and there is a weight of 70kg. It is good for standard anatomy and development
135
what is an IRCP
it is a 3D model of things, and it is Ct image that adjusts for form as reference size and mass. It is for male and female. It is CT adjustments for organs. It helps calculate dose limits. Reference for genderless than gonads added
136
what is the effective dose used for
it is only for reference phantom. It is organ estimated to these reference phantoms however, the tissue weighting factors are for a reference population of both genders and all ages. It is tissue weighting is not specific to gender but is an average. It has organ doses for these two phantoms are combined to calculate E. While organ dose estimates can be calculated for any phantom model or vowel data set, E is defined only for a singular reference person. E is not defined for any other phantom or person
137
what is E used for
E is for occupational and public protection, but E has changed over time, and the definitions of weighting factors and calculation methodology have changed significantly twice since it was first introduced. E is not a physical parameters than can be measured of validated. E describes the radiation source, not the radiation recipient
E folds together cancer incidence and mortality
138
what is E not for
it is NOT for estimating cancer risk, rather it is assesses detriment which includes much more than cancer risk. It is NOT for individuals, and not a patient dose, E is not sued for estimating potential numbers of cancers from small doses in a large population
139
what is the process that this deposits energy in the issue during rad/fluoro
the uncharged particles like photons are transformed into kinetic energy of charged particles. Charged particles directly deposit their energy via excitation ionization or radiation. Energy deposition may be some distance from original interaction- two step reaction
140
what is air kerma
kinetic energy released in air- one step reaction
141
what is X-ray tube output
it is karma/mAs it is in units of mGY/mAs.
142
what is the entrance skin dose
entrance skin dose- entrance skin karma times ratio ( tissue to air) of mass energy absorption coefficients
143
what is the diagnostic reference levels
DRLs are a form of investigation level used as a simple test to identify situations where patient dose is unusally high. Employ an easily measured and standardized quantity. If consistntly exceeded, a local review of procedures and equipment should be performed. IF possible, dose reduction measures should be taken
144
what is the entrance dose and effective dose for abdomen AP
entrance 2.6
| effective .5
145
what is the entrance dose and effective dose for extremity
entrance .1
| effective
146
what is the entrance dose and effective dose for skull (lateral)
entrance .7
| effective .1
147
what is the entrance dose and effective dose for bone survey
entrance 17
| effective 2.8
148
what is the entrance dose and effective dose for EXU (KUB+tomo)
entrance 38
| effective 3.5
149
what happens to the dose area product and effective dose for angiography exams
the increase the dose greatly
150
what is the highest angiography exam
TIPS procedure
151
does CT have a entrance skin dose
no. it just has an effective dose
152
what is the compassion of patient specific risk
it is highly realistic virtual models of patients or the specific patients own CT or MRI data to define the tissues in the relevant organs. Performs a Monte Carlo simulation and calculate the organ doses. Refer to reference data on risk per unit absorbed dose to calculate risk on an organ by organ basis
153
what does BEIR stand for
biological effects of ionizing radiation
