Vocabulary Flashcards
(146 cards)
0
Q
accuracy
A
closeness of a measurement
1
Q
Ipsilateral
A
Same side
2
Q
precision
A
how reproducible or consistent a measurement is
3
Q
electrostatic force or Coulomb F
A
force b/n charged particles like e- & nucleus
4
Q
strong nuclear force
A
force b/n p+ & n in nucleus
6
Q
intensity
A
of photons per unit area
6
Q
divergence
A
widening of the beam, but travel in straight line
7
Q
attenuation
A
- intensity of the beam decr as beam is attenuated
- combo of absorption & scatter
9
Q
absorption means
A
all E given up
10
Q
transmission is
A
passing thru matter w/o being affected
10
Q
mass E absorption coef
A
probability of E absorption thru photon interaction
11
Q
scatter is
A
change in direction
12
Q
saturation
A
add of more voltage does not result in more ionization
13
Q
recombination
A
rejoining of + & - ions which then fails to be counted
15
Q
commissioning
A
calib & gathering of beam data for linac prior to pt tx
16
Q
acceptance testing
A
testing of linac to verify it meets performance stds & safety req prior to pt use
17
Q
threshold dose
A
dose of rad @ which biological response is noted
18
Q
therapeutic ratio
A
- ratio of dose response b/n norm cells & tumor cells
- norm tissue tol dose/tumor lethal dose
19
Q
tort law
A
law governs rights b/n indiv in noncriminal actions
20
Q
integral dose meaning
A
total dose imparted to tissue/med during irrad
22
Q
systemic errors are within
A
measuring device
23
Q
random errors results to
A
chance that are unavoidable
24
Q
blunders
A
- human error
- in calc or improper use of measuring device
25
Q
linac temp
A
- 40 dec C
- 104 deg F
25
cerrobend melting point
74 deg C
26
sentinel node is
primary drainage lymph node
27
chemo drug associated with cardiotoxicity w/radiation
doxorubicin (adriamycin)
28
positive contrast shows as
white; high Z
29
tonsils produce
lymphocytes
30
thymus location
along trachea sup to heart & post to sternum
31
thoracic duct location
L side of body
32
MRI uses ? in body
p+
33
NM Tc 99m emits
gamma rays
34
binding E of nucleus represents
mass defect in the nucleus
35
outer shell e- based on
chemical properties
36
ionization is
addition or removal of an e- from orbit
37
excitation is
incr in E raises an e- to higher orbital shell
38
betas result from
radioactive decay
39
alphas result from
radioactive decay
40
gamma originates from
nucleus
41
isotope has same
Z
42
isotone has same
n
43
isobar has same
A
44
isomer has same
same A & Z
45
LET definition
deposition of E measured per unit path length
46
n LET #
23kev/micrometer
47
monoenergetic (homogeneous) HVL thickness
every HVL is same thickness b/c E of beam always same
48
x-ray & gamma LET #
< 3.5 kev/micrometer
49
what does the 1st HVL do
"hardens" the beam by absorbing low E photons
49
2nd HVL
"hardened" from 1st
51
does the 2nd HVL harden the beam?
yes- "hardened" from 1st
52
does the 3rd HVL harden the beam?
yes-"hardened" from 2nd BUT ***HVL beyond this point does NOT increase
53
E measured in:
J or e- volt
54
HVL definition
absorbed thickness that attenuates orig intensity to 50%
55
mean free path definition
absorbed thickness that attenuates beam intensity to 1/e= 36.8%
56
EPID metal plate converts incident x-rays into
e-
57
homogeneity index is
degree of dose uniformity in target volume
57
brachy task group
TG43
58
QA task group
TG40
59
clinical ref dosimetry output task group
TG51 (new) or TG21 (old)
61
file transfer protocol (FTP) transfers
large files over internet
62
dicom rt contains
images, structure, dose, iso..
63
dicom transfers
digital images
64
PACS stands for
picture archiving communication system
65
photon dmax is depth where what 2 things are =?
dose & kerma
66
pinning is the use of
reference points on skin for s/u
67
triangulation means using
3 points of reference
68
physical penumbra is defined as the
- lat distance b/n 2 specific isodose curves at dmax
| - often 90% & 20%
69
backscatter is the radiation
scattered back toward surface of pt
70
collimator setting is the field size
- set @ collimator when fs at 100 cm
| - so 10x10 coll=10x10 fs on skin at 100 SSD
71
backscatter depends on (3)
-beam E, beam geometry, scatter
72
verification ensures
- volume is correct
| - aka port films
72
bolus
- replaces missing tissue
- reduction of e- beam penetration
- incr skin dose
- compensates for lack of scatter
- unnecessary for superficial beams
74
integral dose is the product of
mass x dose
75
peta
- P
| - 10^15
76
tera
- T
| - 10^12
77
giga
- G
| - 10^9
78
mega
- M
| - 10^6
79
kilo
- k
| - 10^3
80
hecto
- h
| - 10^2
81
deka
- da
| - 10^1
82
deci
- d
| - 10^-1
83
centi
- c
| - 10^-2
84
milli
- m
| - 10^-3
85
micro
- u
| - 10^-6
86
nano
- n
| - 10^-9
87
pico
- p
| - 10^-12
88
femto
- f
| - 10^-15
89
buildup region is where
b/n surface & dmax
90
isodose curve definition
one passing thru points of equal dose & representing % of dose @ ref point
91
geometric field size is defined by
intersection of 50% isodose line & surface
92
beam flatness is produced by a ?
flattening filter that reduces dose along cax @ specific depth, usu 10 cm
93
integral dose unit
J/kg or Gy-kg
94
random errors examples
- accidental movement of pt during setup
| - electronic noise
95
sarcoma is what tissue
connective
96
carcinoma is what tissue
epithelium
97
thoracic duct size relating to R duct
larger
98
betas are emitted from
nucleus
99
betas are
e- that are positively or negatively charged
100
EMR speed
speed of light = 3 x 10^8 m/s or 3 x 10^10 cm/s
101
isotope has different #
n
102
isotone has different #
p+
103
isobar has different #
p+
104
e- resting E
0.511 MeV
105
n resting E
939.5 MeV
106
n mass
1.68 x 10^-26 kg
107
p+ resting E
938.2 MeV
108
p+ mass
1.67 x 10^-27 kg
109
LET unit
kev/micrometer
110
p+ LET #
23 kev/micrometer
111
alpha LET #
53 kev/micrometer
112
polyenergetic (heterogeneous) HVL thickness
thickness increases from 1st HVL to 3rd HVL
113
dicom stands for
digital imaging & communication in medicine
114
PACS stores info for different
modalities
115
photon dmax is max range of what
secondary e-
116
photon dmax is depth where what occurs
e- equilibrium
117
geometric field is same shape as
collimator but not same size
118
cerrobend consists of
- 50% Bi
- 26.7% Pb
- 13.3% Sn
- 10% Cd
119
cerrobend has ? Z
high
120
cerrobend has ? density
high
121
cerrobend cools at what temperature
room
122
cerrobend weight compared to Pb
lighter
123
cerrobend melts at what temp
70deg C or 158 deg F
124
how much dose cerrobend block weigh
5-25lbs
125
what is thickness of cerrobend block
6-8 cm
126
thickness of cerrobend compared to Pb
20% greater
127
cerrobend attenuation
attenuates less than 5% of unblocked beam intensity
128
PTV req'd for
conformal tx plan
129
integral dose unit
gram-rad, kg-Gy, J
130
integral dose compares
dose distrib for different quality beams
131
increase E, ? integral dose
decrease
132
HVT is equivalent to
- penetration
- quality
- hardness
133
HVT is the thickness of material that
decreases intensity of beam to half original value
134
does penumbra depends on distance?
yes
135
1 joule = ? erg
10^7
136
1 Ci = ? Bq
```
3.7 x 10^10
37 MBq (1 mCi)
```
137
1 eV = ? J
1.6 x 10^-19
138
1 R = ? C/kg
2.58 x 10^-4
139
1 rad = ? Gy & ? cGy
10^-2 Gy
| 1 cGy
140
1 rem = ? Sv & ? cSv
10^-2 Sv
| 1 cSv
141
Velocity of light
3 x 10^8 m/s
142
Base of natural logarithms
e = 2.7183
143
Electronic charge q =
1.602 x 10^-19 C
144
Electron mass
9.11 x 10^-31 kg
145
Fluence
Number of photons passing through a unit cross sectional area
146
Fluence rate (flux)
Number of photons passing through a unit cross sectional area per unit time
