Safety Flashcards
(108 cards)
1
Q
required amps for thermionic emission
A
4-6 amps of current
2
Q
required voltage for thermionic emission
A
8-12 volts
3
Q
what is focusing cup made of
A
Molybdenum or nickel
4
Q
what percentage of electrons becomes heat / x-rays during exposure
A
99% heat, 1% x-rays
5
Q
where does the current come from to produce thermionic emission
A
step down transformer
6
Q
what charge does the anode carry
A
positive
7
Q
atomic number of tungsten
A
74
8
Q
what charge does the cathode carry
A
negative
9
Q
material that makes up filament wire
A
thoriated tungsten
10
Q
K shell election binding energy
A
69.53 kev
11
Q
L shell electron binding energy
A
12 kev
12
Q
M shell electron binding energy
A
3 kev
13
Q
maximum number of electrons in shell formula
A
2n^2 where n is the shell number
14
Q
maximum number of electrons in valence shell
A
8
15
Q
90% of all x-ray production is from which interaction
A
Bremsstrahlung
16
Q
the average energy of the central ray is about ___% of the peak energy (kVp)
A
30%
17
Q
interactions that occur at the target / tube
A
Brehmsstralung, characteristic, heat
18
Q
interactions that occur at the tissue
A
photoelectric absorption, compton scatter, coherent
19
Q
which x-rays and interaction are considered diagnostically useful?
A
K-shell characteristic x-rays
20
Q
at 85 kVp, __% of the beam is characteristic
A
15%
21
Q
N shell electron binding energy
A
1 kev
22
Q
forms of radiation that travel as particulate radiation
A
beta and alpha radiation
23
Q
speed of light
A
3 x 10^8 meters/sec
24
Q
what is the difference between x-ray and gamma rays?
A
source of origin
25
what is the relationship between wavelength and frequency?
inversely proportional
26
what is the relationship between wavelength and beam energy?
inversely proportional
27
what is the velocity of all electromagnetic radiation?
speed of light
28
what measures filtration
half value layer
29
which factors effect the half value layer
kVp and filtration
30
image forming radiation is also known as
remnant radiation / exit radiation
31
the absorption of the x-ray beam as it passes through matter
attenuation
32
greatest source of scatter in radiography
the patient
33
during fluoro, greatest source of occupational exposure
compton effect
34
at what angle from the patient will you receive the least amount of radiation
90 degree angle, right angle, perpendicular to
35
every time an x-ray photon gets scattered, it will leave with how much of its original intensity
1/1000th, .001, .1%
36
primary source of patient radiation exposure
photoelectric interaction
37
interaction that is the source of biological damage for the patient
photoelectric absorption
38
at 70 kVp __% of x-rays undergo coherent scattering
3%
39
approximately __% of x-rays incident on the patient reach the IR
1%
40
t/f atomic number of tissue increases the amount of scatter
false
41
what is the unit of absorbed dose
gray
42
what is the unit of absorbed dose equivalent
sievert
43
rad to gray conversion
x .01
44
rad to mGy conversion
x10
45
quality factor for gamma rays
1
46
quality factor for beta particles
1
47
quality factor for protons
5
48
quality factor for fast neutrons
10
49
quality factor for alpha particles
20
50
meaning of KERMA
kinetic energy released per unit mass
51
measures the number of ionizations in air
exposure (C/kg)
52
measures the energy of ionizations in the air
air kerma (Gy)
53
used to compare risk of cancer based on different types of radiation and different types of tissue
effective dose
54
which dose response relationship is radiation protection standards based on
linear non-threshold
55
which dose response relationship is diagnostic x-ray
linear non-threshold
56
what is the single most radiosensitive cell in the body
lymphocyte
57
ability to produce biological damage
relative biologic effectiveness (RBE)
58
what is the relationship between RBE and LET
directly proportional
59
radiation interaction with water is called
radiolysis
60
percentage of the body that is water
80 ish %
61
cell dies without attempting to divide (2 names)
interphase death or apoptosis
62
cell division is known as
mitosis
63
germ cell division is known as
meiosis
64
dose required for mitotic delay
.01 Gy or 10 mGy
65
dose required for reproductive failure
1-10 Gy
66
which part of the eye is most radiosensitive
lens
67
what dose to the eye will cause partial or complete vision loss
2 Gy
68
what dose will cause skin erythema
2 Gy
69
what dose will cause epilation (hair loss)
3 Gy
70
dose for female sterility temporary and permanent
2 Gy temp, 5 Gy permanent
71
dose for male sterility
.1 Gy depressed sperm count, 5-6 Gy permanent
72
what dose can result in genetic mutations
100 mGy or .1 Gy
73
cancer causing agents are called
carcinogens
74
dose required for hemopoietic syndrome
1-10 Gy to whole body
75
when does death occur for hemopoietic syndrome
3-6 weeks after exposure
76
dose required for gastrointesinal syndrome
10-50 Gy
77
when does death occur for gastrointestinal syndrome
1 week following exposure
78
dose required for CNS death or cerebrovascular syndrome
50 Gy
79
when does death occur for CNS syndrome
death within hours or days
80
as the complexity of the system increases, what happens to threshold dose and survival time
complexity increases, threshold increases, survival time decreases
81
minimum filtration for 70 kVp and above
2.5 mm Al equivalent
82
how do you reduce ESE to vitally sensitive organs
turn back to the beam (skin exposure)
83
minimum filtration for below kVp
.5mm Al eq
84
minimum filtration 50-70 kVp
1.5 mm Al eq
85
digital imaging eliminates retakes due to overexposure of up to ___% and underexposure up to ___%
500% over, 80% under
86
ALARA meaning
as low as reasonably achievable
87
body part thickness to use a grid
10 cm thick
88
good middle ground pulse per second for fluoro
7.5 pps
89
minimum lead equivalent required for lead aprons
.25 mm Pb
90
recommended and most widely used lead thickness for shielding
.5mm Pb
91
what percentage of radiation is blocked at .5mm Pb at 75 kVp
88%
92
largest source of natural radiation
radon gas
93
largest source of artificial exposure
medical imaging
94
fluoro curtain is what lead thickness
.25 mm Pb
95
minimum lead equivalent required for lead aprons for use in fluoro
.5mm Pb
96
primary protective barrier lead equivalent required
1/16 inch, .16 cm, 1.6 mm
97
primary protective barrier must be how high
7 feet
98
secondary protective barrier lead equivalent required
.08 cm or .8 mm Pb
99
fluoro exposure switch must be what type
dead man switch
100
functional component of TLD
lithium fluoride
101
how to get readings from TLD
heating up lithium fluoride chip
102
functional component of OSL
aluminum oxide
103
how to get readings from OSL
laser light reading luminescence
104
dose limit for embryo
5 mSv for entire period, .5 mSv for each month
105
annual whole body exposure limit occupational
50 mSv
106
annual lens of the eye exposure limit occupational
150 mSv
107
annual extremity, breast, lung, gonad etc exposure limit occupational
500 mSv
108
cumulative effective limit occupational
10 mSv x age in years
