radiation protection Flashcards
1
Q
what are the 3 basic principals to always keep in mind in order to protect yourself while working
A
time
distance
shielding
2
Q
who evaluates information on biologic effects and provides recommendations on dose limits introduced the concept of AlARA
A
ICRP
International Council on Radiation Protection
3
Q
Reviews ICRP regulations and chooses US radiation protection criteria
A
NCRP
National Council on Radiation Protection and Measurement
4
Q
Regulates the design and manufacture of diagnostic radiologic equipment as well as conducts onsite inspections of equipment
A
FDA
Food and Drug Admin
5
Q
functions as a monitoring agency in places of employment and regulates occupational exposure to radiation
A
OSHA
Occupational Safety and Health Administration
6
Q
Every x-ray tube must be contained w/in a protective housing that reduces radiation leakage to less than _ at a distance of _ from the housing
A
10 mr/hr
1 meter
7
Q
A room’s SID indicator must be accurate to w/in _ of the indicated SID
A
2%
8
Q
the x-ray beam and light beam must coincide to w/in _ of the SID
A
2%
9
Q
for any given technique radiation output should be constant from one exposure to another. Reproducibility of x-ray exposure should not exceed _ intensity change
A
5%
10
Q
when different mA stations are used and exposure time is adjusted for constant mAs, output radiation intensity should remain constant. The max. acceptable variation in linearity is _ change
A
10%
11
Q
kV must be accurate to w/in _ kv of that set on the control panel
A
4
5% varience
12
Q
a protective lead apron should be assigned to each portable machine. The exposure switch of a portable x-ray machine must allow the operator to remain at least _ meters from the tube during exposure
A
2 meters
13
Q
the purpose of adding filtration to an x-ray beam is to _ of the beam and to _ patient dose by filtering out low energy x-ray that have little chance of getting to the image receptor.
A
increase quality
patient dose
14
Q
what reduces both ESE and organ dose
A
filtration
15
Q
by eliminating the weaker photons in the beam, the average beam energy is actually
A
increased
16
Q
filtration of the ray beam has two components
A
inherent and added filtration
17
Q
the glass window of the tube and the insulating oil surroundng the x-ray tube create_
A
inherent filtration
18
Q
inherent filtration measures
A
0.5 mm/Al equivalent
19
Q
a 1.0 Al plate and the 1.0 mm/Al equivalent collimator mirror comprise the tubes
A
added filtration
20
Q
what is the total for added filtration
A
2.0
21
Q
total filtration =
A
inherent + Added filtration
22
Q
total filtration of general purpose x-ray tubes that operate at over _kV is
A
70
2.5 mm/Al equivalent
23
Q
is used to determine the tubes total filtration is the amount of filtration that redices the intensity of the x-ray beam to half of its original value
A
1/2 value layer
24
Q
HVL is measured
A
annually
25
there is an opening in the table at the gonadal level for the moving of the Bucky tray
buck slot cover
26
bucky slot cover needs to be covered with at least
.25 mm/Pb eq
27
protective curtain of at east
0.25 mm/Pb eq
28
protective curtain should be positioned between the
fluoroscopist and the patient
29
what is the main source of radiation during a fluoro exam
scatter from pt.'s body
30
since the pt is constantly being irradiated during fluoroscopy the mA range used is between
2 and 5, this helps lower pt dose
31
an audible signal will sound when fluoro time has exceeded 5 min during an exam
fluoro timer
32
the intensity of the beam should not exceed _ w/standard fluoro a _ with high level fluoro (angiography and c-arms)
10 R/min
| 20 R/min
33
the x-ray beam actually pulses on and off in quick succession in order to reduce pt dose.
pulse fluoro
34
this has the added effect of increasing tube life
pulse fluoro
35
when the fluoroscopist shuts off the x-ray beam, the last image on the monitor remains there. Again this reduces pt dose
last image hold
36
min. source to skin distance
fixed fluoro
mobile fluoro
15"
| 12"
37
fluoroscopy units must be operated with a
dead mans switch
38
one should be assigned to each portable machine in order to protect the radiographer
lead aprons
39
exposure switch cord should be at least
2 meters
| 6ft long
40
where to stand during the exposure
tech should stand at a 90 degree angle to the pt
41
this prevents the primary beam from escaping the room. Walls that are struck by the primary beam must have _ which extends from the floor up to
1.6 mm Pb/eq
7'
1/16"
42
prevents secondary radiation from escaping the room. Walls and doors that are to be struck by the secondary beam must have
.8 mm Pb/eq
| 1/32"
43
what is considered a secondary barrier
control booth barrier
44
the lead glass window must have
1.5 mm Pb/eq
45
lead aprons and gloves must be at least _ Pb/eq
| fluoro, the lead aprons must be _ Pb/eq
.25 mm Pb/eq
| .5 mm Pb/eq
46
protective glasses must be at least _ mm Pb/eq
.35 mm Pb/eq
47
thyroid shield must be at least _ mm Pb/eq
0.5
48
most commonly used to detect radioactive contamination
Geiger-Mueller counter
49
commonly used to measure primary beam for purposes of equipment evaluation
Ionization chamber (cutie Pie)
50
this is the basis for the gamma camera in nuclear medicine and is used in the detector arrays of ct imaging systems.
scintillation detectors
51
used to detect alpha and beta particles
proprtional counter
52
most commonly used & measures radiation that passes through a thin strip of aluminum oxide. When read, its struck by a laser light, then luminesces in proportion to the amount of radiation exposure received.
OSL
53
OSL is read
quarterly
54
OSL contains
aluminum, copper tin
55
contains tow pieces of film in a light tight envelope. Radiation exposure is measured by checking the optical density of the film
film badges
56
film badges are read
after 1 month use
57
contains a crystalline form of lithium fluoride which stores energy when exposed to radiation. When it is heated in order to read it, the heat causes crystals to emit light in proportion to the radiation that has struck the dosimeter. The crystals then return to their natural state and can be reused
TLD
58
TLD's are read
quarterly
59
THIS IS THE MOST RADIOSENSITIVE TYPE of personnel dosimeter. It contain an ionization chamber that measures radiation exposure. It's reusable and provides an immediate reading. It is often used by employees of nuclear power plants
Pocket Ionization Chamber PIC
60
PICs are read
daily
61
Occupational Exposure Effective dose
Annual
cumulative
5 rem
| 1 rem x age
62
equivalent annual dose for tissues and organs
Lens of eye
Thyroid, skin, hands, and feet
15 rem
| 50 rem
63
Public annual exposure
.5 rem
64
child under 18
.1 rem
65
fetus total dose
| monthly dose
.5 rem
| .05 rem
66
radiation that is capable of removing an electron from an atom. This creates both positively and negatively charged particles
Ionizing radiation
67
the study of the effects of radiation on living tissue
radiobiology
68
occurs when ionizing radiation directly strikes the DNA or RNA (target molecule) of a cell, disrupting cell function. The most common result of this is that it has no effect at all on the cell, however, sometimes it may cause mutations or even cell death
direct effect (action)
69
since cells are mostly made of water, the probability that it will be ionized by radiation is greater. This can cause the water molecule to form a hydrogen peroxide molecule which is toxic to the cells. Again, the most common result of radiolysis is that it has no effect but it can cause the creation of free radicals in the water molecules of the cell
indirect effect (action)
70
a molecule containing a single unpaired electron in its outermost shell. Free radicals are unstable, highly reactive and can do a great deal of damage to other molecules. This process can be reversible: ionized atoms can become neutral again by attracting a free electron and molecules can be mended by repair enzymes
free radicals
71
the average annual dose of radiation for Americans is _ and stems from 2 sources
360 mrems
| Natural and Manmade
72
Natural radiation accounts for
49%
73
manmade accounts for
51%
74
from radioactive materials in the crust of the earth
terrestrial radiation
75
examples for terrestrial radiation is
uranium, radium, thorium, radon
76
what is responsible for 49% of all US radiation exposure
Radon Gas
77
From the sun and solar system and the greatest intensity occurs at high altitudes
cosmic radiation
78
from radioactive atoms that make up a small % of the body's tissues
internal radiation
79
Manmade radiation consists of
medical and industrial
80
what are the largest sources of artificial radiation
x-rays and nuclear medicine
81
consumer products that contain radiation
airport survelliance systems
ionization smoke alarms
luminous timepiece dials
porcelain denture
82
biologic effects are related to the radiation absorbed dose,
Rad (Gray/Gy)
83
1 rad= _Gy
| 1Gy= _rad
0.01
| 100
84
what is used to express the quantity of radiation received by radiation workers and populations. some types of radiation produces more damage than x-rays
REM (Seivert/Sv)
85
_=quality factor x rad
Rem
86
1 rem= _ Sv
| 1 Sv= _Rem
.01
| 100
87
what applies to x-rays and gamma rays and their interactions with air. Radiation monitors and the output of x-ray imaging systems
Roentgen/coulumb/kg
88
a unit of the quantity of radioactive material and radioactive decay of that material
Curie/Ci (BQ)
89
states that the radiosensitivity of cells varies with the maturation, metabolism and differentiation of the cells
law of B & T
90
Law of B &T
stem cells are _, mature cells are _
cells with high metabolic activity and high growth rate are _
complex or highly specialized cells are
radiosensitive, radioresistant
radiosensitive
radioresistant
91
what is a measure of the rate at which energy is transferred from ionizing radiation to soft tissue. It is a method of expressing potential biologic damage from radiation
linear energy transfer
92
the LET of diagnostic x-rays is appx
3 keV/micrometer
93
the ability of radiation to produce a biologic response (damage_ increases as the LET of the radiation
increases
94
when LET is high, ionization are _, so damage is
high
| high
95
what is designed to compare the doses of different types of radiation needed to produce the same biologic effect
Relative Biologic Effectiveness
96
RBE =
reference radiation
-----------------------
test radiation
97
Diagnostic x-rays have an RBE of
1
98
Radiation with a lower LET than x-rays have an RBE of less than
1
99
those with a higher LET have an RBE of more than
1
100
tissue is more sensitive to radiation when irradiated in an oxygenated or aerobic state
oxygen effect
101
demonstrate graphically the relationship between the amount of radiation absorbed by a subject and the amount of damage observed
dose response relationships
102
the point at which biologic effects are observed when a radiation dose is administered
threshold
103
a relationship in which any radiation dose can produce a biologic effect
nonthreshold
104
when the radiation dose is doubled the response to radiation is doubled
linear
105
responses will increase rapidly or taper off as dose increases
non-linear
106
biologic effects that will be handed down to generations yet unborn
genetic effects of radiation
107
this is the average annual gonadal dose to members of a population who are of childbearing age.
GSD
108
In the US, the GSD is
20 mrem
109
when living organisms that have been exposed to radiation suffer biologic damage
somatic effects
110
what are divided into early and late, nonstochastic and stochastic effects
somatic effects
111
are observable within minutes to months of radiation exposure and are always nonstochastic
early effects
112
are observable 6 months or more after radiation exposure. Late effects can either be stochastic or non stochastic
late effects
113
are randomly occurring mutational changes that are not dependent on dose amount. the more times you receive radiation the better your chances of receiving an effect and are always late effects
stochastic effects
114
stochastic effects are always
late effects
115
nonstochastic and early effects
erythmia, ARS, Epilation, and desquamation,
116
linear, nonthreshold late effects
cancer,leukemia, cataracts
117
nonlinear, threshold late effects
cataracts, organ atrophy, sterility, 50/30, and 50/60
118
this system is the most radiosensitive in the body. It manufactures the elements of blood in the bone marrow and obtains the lymph nodes, spleen, and thymus.
Hemopoietic
119
what are a subcategory of white blood cells
lymphocytes
120
lymphocytes live for only _hrs and are the most radiosensitive cells in the body
24
121
the lining of the GI tract divides very rapidly and is thus considered very radiosensitive
gastrointestinal system
122
-% of the cells lining of the intestines are replaced every day
50
123
what is the most sensitive section of the GI tract
small bowel
124
reproductive cells are extremely _ radiation.
sensitive
125
what are second to lymphocytes in radiosensitivity
sperm cells
126
skin replaces itself only _%
2 % daily
127
eyes and thyroid are
radiosensitive
128
the fetus is the most sensitive during the
first trimester
129
what are possible biological effects of radiation during pregnancy
prenatal death, congenital abnormalities, malignancy induction, general growth impairment and mental retardation
130
the sequence of events after high radiation exposure, usually leading to death within weeks
Acute radiation syndrome
131
There are 3 different dose related conditions associated with ARS
Hemotologic syndrome
Gastrointestinal syndrome
central nervous system syndrome
132
syndrome is characterized by a reduction in the number of platelets and both red and white blood cells and loses its ability to defend against infection
hematologic syndrome
133
hematologic syndrome the minimum whole body dose is
200 rad
134
death usually occurs because of severe damage to the lining of the intestine
GI syndrome
135
Gi syndrome the min. whole body dose
5000 rad
136
what are the 3 periods related to ARS
prodromal
latent
manifest
137
consists of acute symptoms within an hour or two of exposure and can continue for a day or two
prodromal pd
138
subject is free of visible effects, last for a few hours to a couple of weeks
latent period
139
dose related period in which the subject displays the effects of the 3 ARS syndromes
manifest Illness
140
follows a nonlinear, threshold dose response relationship
ARS seath
141
the dose of radiation to the whole body that will result in death to 50% irradiated subjects within 60 days
50/60
142
the LD 50/60 in humans is
350 rad
143
Death
anatomic site
min. dose
whole body
| 100
144
Erythema
anatomic site
min. dose
small field
| 200
145
Epilation
anatomic site
min. dose
small field
| 300
146
gonadal dysfunction
anatomic site
min. dose
small field
| 10
