Test 1 Study Flashcards
1
Q
f(x) of lysosomes
A
digest cell fragments thru phagocytosis; suicide sacks
2
Q
What happens to the transmission of XRs as tissue Z increases?
A
reduces transmission
3
Q
this results in a change/loss of base; transfers incorrect genetic code to 1 of 2 daughter cells; creates abnormal gene (genetic mutation)
A
point mutation
4
Q
irradiation w/in the body
A
in vivo
5
Q
what cell type is most radiosensitive?
A
Spermatogonia, lymphocytes
6
Q
inner shell interaction that will cause ionization
A
photoelectric effect (total absorption)
7
Q
interactions that do not occur in diagnostic rad
A
pair production & photodisintegration
8
Q
responsible for protein synthesis in the cell?
A
ribosomes
9
Q
outer shell interaction that will cause ionization
A
compton effect aka wide angle scatter
10
Q
which model applies to biological targets (enzymes, viruses, bacteria, other cimple cells)?
A
single-target single-hit
11
Q
rad damage to DNA can result in? (3)
A
main-chain scission, cross-linking, point lesions
12
Q
what makes up the structural component of the cell membrane?
A
lipids
13
Q
what happens to the photon during the Compton effect?
A
it continues in a different direction w reduced energy
14
Q
what is the relationship of no response expected below a certain dose value?
A
threshold
15
Q
dose is delivered continuously but at a lower rate is called?
A
protraction
16
Q
how does cross-linking affect the viscosity of the molecular solution?
A
(spurs that stick/attach to other mol.’s) –> increases viscosity
17
Q
rad damage that you can determine that rad exposure is the source of damage (aka effects from a nuclear blast)
A
non-stochastic/deterministic
18
Q
LET of diagnostic XR?
A
3 keV/µm
19
Q
what are the oxygen conditions in invitro rad?
A
hypoxic
20
Q
which model applies to more complex bio systems (i.e. human cells)?
A
multi-target single-hit
21
Q
reduction of nutrient mol.’s for energy
A
catabolism
22
Q
irradiation of mammalian cells w high LET rad follows the ___________ model
A
single-target single-hit
23
Q
define recoil e-
A
In photoelectric effect, it is the ejected e-
24
Q
f(x) of mitochondria?
A
produce energy
25
what % of the body is composed of oxygen?
25.7%
26
subject contrast depends on what?
differential absorption
27
which interaction produces a positron & a negatron?
pair production
28
What happens to the differential absorption of photoelectric interactions as tissue Z increases?
greatly increase (Z^3)
29
early rad effects are what kind of effects?
non-stochastic/deterministic
30
What happens to the transmission of XRs as tissue mass density increases?
proportionally reduces
31
when does interphase death occur?
when the cell dies before replicating
32
how does the energy of the incident XR relate to the scattered XR in coherent scatter?
same (Ei = Es) (same wavelength)
33
rad-induced cancer, leukemia, & genetic effects follow what kind of dose-response relationship?
linear-nonthreshold
34
human cells are most radiosensitive during which phase of the cell cycle?
M (Mitosis)
35
what is the most radiosensitive tissue in the body?
lymphoid/blood forming tissue (bone marrow)
36
the lowest amount of radioactivity, to which most highly radiosensitive tissues will respond, is _____ rads
200
37
ex.'s of non-stochastic/deterministic effects?
rad induced skin burn (erythema), organ atrophy, cytogenetic damage; ARS/somatic effects (where you are exposed to rad and suffer the damage)
38
As LET of rad increases, the ability of ionizing rad to produce a biological response \_\_\_\_\_\_
increases
39
free radicals have excess e that can be transferred to other mol.'s to disrupt bonds & produce what?
point lesions
40
what causes the emission of characteristic rad?
In photoelectric effect, after the photoelectron has been ejected, an outer shell e- falls into the inner shell to fill the void and releases char. rad.
41
what oxygen effects produce less radiosensitivity?
hypoxic conditions
42
what is the relationship of any dose, regardless of size, producing a response?
non-threshold
43
where is RNA located?
cytoplasm
44
scatter deflected at a 180º angle is called? (from what XR interaction?)
backscatter; compton effect
45
what are the comm. channels of the cell?
ER
46
differential absorption in bone & soft tissue result from ___________ interactions, which greatly depend on \_\_\_\_\_\_\_\_\_\_
photoelectric; tissue Z
47
what dose method is better for cell survival?
fractionation (allows T for repair)
48
irradiation outside of the cell or body
in vitro
49
coherent scatter aka? (3)
unmodified, classical, or Thompson scattering
50
what is the breakage of the backbone of the long chain macromolecule (DNA); changes long single mol. into many smaller mol.'s
main chain scission
51
the 2 nucleic acids in the cell
DNA & RNA
52
what are the 5 interactions of XR/gamma rays w matter? (in order of least to greatest, in terms of power of XR)
coherent scatter, photoelectric effect, compton scatter, pair production & photodisintegration
53
breakage of the backbone of the long-chain macromolecule?
main-chain scission
54
the probability of photoelectric effect is inversely proportional to what?
the third power of the XR energy (1/e)^3
55
at 70 kVp, how many XRs undergo coherent scattering? and what does it cause on the film?
5%; slight fog
55
when are photoelectric interactions more likely to occur?
if XR photon energy is greater than (but close to) the binding energy of the e-; (as energy of photon increases, there is less chance for photoelectric interaction)
55
differential absorption _______ as the kVp is reduced
increases
55
the interaction of XRs w tissue is proportional o the __________ of the tissue (regardless of type of interaction)
mass density
55
at what stage in the sequence of events after rad exposure, is it possible to repair rad damage & recover?
nearly every stage
55
when is rad-induced chromosome damage analyzed?
metaphase
55
the process whereby genetic cells undergo reduction division
meiosis
55
\_\_\_\_\_\_ cells are more sensitive to rad than ______ cells
stem; mature
55
what is the RBE of diagnostic XRs?
1
55
how do you calculate oxygen enhancement ratio?
OER = dose necessary under anoxic conditions to produce a given effect / dose necessary under aerobic conditions to produce same effect
55
skin effects resulting from high-dose fluoro follow what kind of dose-response relationship?
sigmoid-type
55
rad interaction w macromolecules also can result in disruption of single chem bonds, producing what?
point lesions
55
what consists of catabolism & anabolism?
metabolism
55
the excess energy of a free radical can be transferred to DNA which can result in what?
bond breaks
55
what is the proliferation of genetic cells?
meiosis
55
how many daughter cells are produced in meiosis?
4
55
3 early rad effects?
skin erythema, organ atrophy, and cytogenetic damage
55
the 2 primary forms of Xr interaction in the diagnostic range?
Compton scatter & photoelectric absorption
55
how does the Z affect the probability of photoelectric interactions?
more likely to occur when e-'s are more tightly bound to orbit (high Z); directly proportional to third power of Z, or Z^3
55
interaction that causes total absorption of incoming photon
photoelectric effect
55
the energy requirement for pair productions?
above 1.02 MeV
55
factors that affect differential absorption? (7)
tissue thickness, Z of tissue, type of tissue, tissue mass density, kVp, contrast media, & scatter rad
55
production of lg mol.'s from small mol.'s for form/f(x)
anabolism
55
comm. channels in cell?
ER
55
cell division of genetic cells?
meiosis
55
in mitosis, the stage where chromosomes split at centromere & slowly migrate toward spindle (pole)
anaphase
55
relationship btw LET & OER
indirect
55
when water is irradiated, it dissociates into other molecular products ---\> it ionizes & dissociates into 2 ions
radiolysis of H2O
55
what is an uncharged mol. containing a single unpaired e- in the outer shell?
free radical (which is more reactive bc it is seeking a pair)
55
What happens to the differential absorption of Compton interactions as XR energy increases?
they reduce (1/e)
55
sufficient rad can _________ an organ
shrink/atrophy
55
what provides structure/support & functions as enzymes, hormones, & antibodies?
amino acids
56
what are the oxygen conditions in invivo rad?
aerobic
58
bc of differential absorption of contrast agents, Iodine is used for what kind of imaging studies?
vascular, renal, & biliary
59
the lethal effects of cell irradiation are measured by \_\_\_\_\_\_\_\_
cell survival
60
what is the relationship of a response that is not proportional to dose?
non-linear
61
what happens to viscosity during main chain scission?
reduces viscosity
63
what indicates that the cell will recover in time?
if the rad dose is not sufficient to kill the cell before it's next division
64
3 late rad effects?
cancer, leukemia, and cataracts.
65
what tissue is the least sensitive to rad?
nerve tissue
66
What happens to the differential absorption of photoelectric interactions as tissue mass density increases?
proportionally increase
67
how are LET & RBE related?
directly
68
what is the effect of oxygen in radiosensitivity?
more oxygen --\> more radiosensitivity
69
pyrimidines?
thymine & cytosine
70
what indicates that the cell can recover readily from sublethal rad damage
a lg Dq
71
\_\_\_\_\_\_\_\_ is the cell cycle phase during which the chromosomes become visible, divide & migrate to daughter cells
mitosis
73
suicide bags in cell?
lysosomes
74
interaction in which the incoming photon only uses a percentage of it's energy
Compton effect (wide angle scatter)
76
half as much DNA is present in \_\_\_\_, as in \_\_\_\_\_.
G1; G2
77
what base bondings are possible in DNA?
adenine-thymine & cytosine-guanine
78
when are human cells most radioresistant?
in late S
79
what is the most T variable of cell phases?
G1
81
chief f(x) of carbohydrates
provide fuel for cell metabolism
82
theory that a little rad is good for you bc it stimulates the hormonal/immune responses to toxic enviro agents?
radiation hormesis
83
What happens to the differential absorption of photoelectric interactions as XR energy increases?
they greatly reduce (1/e^3)
84
what occurs bc of Compton Scatter, photoelectric effect & XRs transmitted thru pt
differential absorption
85
high LET means more what?
ionizations --\> more probability of interaction w target mol. (DNA)
86
in mitosis, the stage where chromosomes appear aligned in the equator
metaphase
87
what has a greater chance to occur when the e- is more tightly bound in its orbit? (this is indicated by what?)
photoelectric interactions; high atomic no.
88
what are stem cells, precursor cells, & undifferentiated cells?
immature cells
89
which XR interaction involves a photon interacting w an inner shell e-, using ALL of its energy to eject the e- out of it's orbit?
photoelectric effect
90
what is responsible for protein synthesis in the cell?
ribosomes
91
what % of the body is composed of hydrogen?
60%
92
what are the factors that affect the probability of photoelectric interactions?
binding energy of e-, atomic number of absorbing material, & tissue mass density
94
how many daughter cells are produced in mitosis?
2
96
what indicates radioresistant cells
a lg D0
97
chem agents that enhance the effect of rad
radio-sensitizer
98
what N bases make up purines?
adenine & guanine
99
Explain the law of Bergonie & Tribondeau
radio sensitivity of living tissue varies w maturation & metabolism; younger tissue/immature cells w high metabolic activity (or higher proliferation rate; rapid cell division) are more radiosensitive; and mature cells are more radioresistant
100
in mitosis, the stage where DNA becomes more prominent
prophase
102
what is characteristic of radiosensitive cells?
a small D0
103
the loss of contrast from noise is from _______ interactions
Compton
105
rad damage that may/may not cause an issue down the line; can't really determine if the source of the damage was rad. is known as what kind of effects?
stochastic/non-deterministic
106
what happens to the direction of the scatter in coherent scattering?
direction will be different than the incident XR, usually in forward direction (generally less than 20º)
107
what dose method increases tissue damage?
protraction (bc administered all at once)
108
the principal effect of radiation of humans is ______ (bc the body is 80% water)
indirect
109
if the initial ionizing event occurs on the target mol., the effect of rad is what?
direct
110
RBE of alpha particle?
20
111
hits occur through what effect(s)?
direct & indirect
112
how can you calculate the probability of a photoelectric interaction w XR energy (e)?
(1/e)^3
113
ex.'s of stochastic/non-determinsitc effects?
cancer, leukemia, cataracts; genetic effects (where you are exposed to rad, but your offspring get damaged)
114
the angle of Compton scatter can range from ____ to \_\_\_\_
0 - 180º
115
effects from high dose exposure, exhibiting early responses and acute rad syndrome (ARS)
non-stochastic/deterministic effects
116
the probability of Compton scattering is ________ proportional to XR energy and ________ of atomic number
inversely; independent
117
what % of the body is composed of carbon?
10.7%
119
what is a measure of the capacity to accumulate sublethal damage & the ability to recover from sublethal damage
Dq
121
what is the product of absorption and scattering?
attenuation
122
the process of cell meiosis results in cells w _____ chromosomes ea
23
123
what is the formula for XR energy in photoelectric effect?
Ei = Eb + Eke, (Ei - incident XR energy, Eb - e- binding energy, Eke - kinetic energy of e-)
125
what can cause cassette hinge img on radiograph?
backscatter
126
which XR interaction is principally important in diagnostic rad? why?
Photoelectric effect; contrast
127
how many amino acids are used in protein synthesis?
22
129
where is DNA located?
nucleus
130
late rad effects are what kind of effects?
stochastic/non-deterministic
131
f(x) of ER
comm. channels
132
what two things make up lipids?
fatty acids & glycerol
134
what model does irradiation of mammalian cells w high-LET rad follow?
the single-target, single-hit model
135
if the initial ionizing event occurs on the target mol (DNA) it is what kind of effect?
direct
136
arrange in order of INCREASING tissue mass density: fat, air, bone, tissue
- air (1.3) - fat (910) - soft tissue (1000) - bone (1850)
137
radiation effects from low rad exposure that triggers late responses?
stochastic/non-deterministic
139
what happens to the target atom during Compton Effect?
will ionize target atom
140
what is the ejected e- called in Compton Effect?
Compton e- or secondary e-
142
which is the most radiosensitive target mol. in the human cell?
DNA
144
the rate at which energy is transferred from ionizing rad to soft tissue is known as?
linear energy transfer (LET)
145
stages of somatic cell division?
(mitosis) prophase, metaphase, anaphase, telophase
146
what is the proliferation of the somatic cell?
mitosis
147
interaction in which incoming photon uses all of its energy
photoelectric effect
148
power house of cell?
mitochondria
149
lethal effects of rad are determined by observing what?
cell survival (not cell death)
151
diagnostic XR imaging is performed under what conditions?
of full oxygenation
152
study of the effects of ionizing rad on bio tissue
radiobiology
154
the energy requirement for photodisintegration?
above 10 MeV
155
which interaction causes an annihilation/anti-matter reaction?
pair production
156
how do you calculate relative biologic effectiveness?
RBE = dose of standard rad necessary to produce a given effect / dose of test rad necessary to produce the same effect
157
what interaction is aka "wide angle scatter"
Compton effect
158
at 90 kVp, about \_\_\_% are Compton & \_\_\_% are photoelectric (remaining is coherent)
67% - compton, 33% - photoelectric
159
when are human cells most radiosensitive?
in M
160
the LET of diagnostic XRs is approx?
3 keV/µm
161
chem compounds that reduce the sensitivity of rad
rad-protectors (not commonly used bc very toxic and may be more harmful than rad)
162
how does rad interact w matter?
randomly
163
interaction that will not cause ionization
Coherent aka unmodified aka Classical/Thompson scatter
164
bc of differential absorption of contrast agents, Barium is used for what kind of imaging studies?
GI
165
what are the substances produced during radiolysis of water?
hydrogen peroxide (poisonous), hydroperoxyl (poisonous), organic free radicals
166
the principal effect of rad on humans is what?
indirect
167
f(x) of ribosomes
protein synthesis
168
to img small differences in soft tissue, one must do what to get max differential absorption?
use low kVp
169
which interaction causes backscatter?
Compton scatter (@ 180º)
170
What happens to the differential absorption of Compton interactions as tissue mass density increases?
proportionally increase
171
how does the binding e of e-'s affect the probability of photoelectric interactions?
more likely to occur if the XR e is greater, but close to the binding e of the e-; as e increases, less chance it will occur bc inversely proportional to 3rd power of XR e, or (1/e)^3
172
how can you calculate the probability of a photoelectric interaction w atomic number of the absorbing material?
Z^3
173
production of lg mol.'s for form & f(x)
anabolism
174
some macromolecules have small, spur-like side structures that extend off the main chain & can behave like it's sticky and attach to neighboring macromolecules, this process is?
cross-linking
175
the probability of photoelectric effect is directly proportional to what?
the third power of the atomic no. of the absorbing material (Z^3)
176
(Interphase) post DNA synthesis gap
G2
177
the reduction of nutrient mol.'s for energy
catabolism
178
what is interphase?
cell cycle btw mitotic events; period of cell growth btw divisions
179
\_\_\_\_\_\_\_\_ is the process of reduction division, & occurs only in reproductive cells
meiosis
180
what % of the body is composed of nitrogen?
2.4%
181
4 results of coherent scattering?
change in direction of XR, NO change in energy, NO energy transfer, NO ionization
182
what % of the body is composed of proteins? lipids?
15%; 2%
184
if there were no wasted hits (uniform interaction), ____ is the dose that would be sufficient to kill 100% of the cells
D37
186
Recovery = ? + ?
intracellular repair & repopulation
187
why are free radicals energetic mol.'s?
bc of their unique structure
188
if the hit occurs in tissue or water, it is what kind of effect?
indirect
189
what is more radiosensitive? in vivo or in vitro?
in vivo
190
how does age affect radiosensitivity?
most sensitive before birth; sensitivity decreases until maturity, and then become somewhat more radiosensitive in old age
191
What happens to the transmission of XRs as XR energy increases?
increases transmission thru tissue
192
the 2 major parts of the cell?
nucleus & cytoplasm
194
(Interphase) pre-DNA synthesis phase
G1
195
the act of a cell(s) to reproduce/multiply in number
cell proliferation
196
RBE of diagnostic XR?
1
197
what is another method of explaining rad. quality & determining the value of the rad weighting factor (Wr) used in rad protection?
LET
198
what principles of differential absorption make iodine and Barium good contrast agents?
high Z's & higher mass density than soft tissue
199
a hit is not simply an ionizing event but rather an ionization that does what?
inactivates the target mol.
200
why does dose protraction & fractionation cause less effect?
bc T is allowed for intracellular repair & tissue recovery
201
interaction that is responsible for the majority of fog in diagnostic rad?
Compton effect
202
which interaction absorbs the entire photon in the nucleus and becomes radioactive, then stabilizes by emitting neutrons, protons, alpha particles, fragment clusters, &/or gamma rays?
photodisintegration
203
how are OER & LET related?
indirectly
204
radiation-induced genetic damage follows _______ \_\_\_\_\_\_\_ dose response relationship
linear non-threshold
205
combined effect of catabolism & anabolism
metabolism
206
differential absorption occurs bc of \_\_\_\_\_\_\_\_\_\_, \_\_\_\_\_\_\_\_\_, & ______ transmitted thru the pt
compton scattering, photoelectric effect, & XRs
207
radiation induced rad damage is analyzed during which stage?
metaphase (of mitosis)
208
at low rad doses, what is considered to be the cellular rad damage that results in the stochastic rad effects observed at the whole-body level?
point lesions
209
bc of it's very high LET, what is the highest ionization radiation?
alpha particles
210
how does the mass density affect the probability of photoelectric interactions?
directly proportional to mass density
211
what is the relationship of a response that is directly proportional to dose?
linear
212
compton scattering reduces what?
img contrast
213
(Interphase) DNA synthesis phase
S
214
in mitosis, the stage where chromosomes change to DNA & nuclear membranes close off
telophase
215
the combined processes of what and what contribute to recovery from rad damage?
intracellular repair & repopulation
216
which scattering is of little importance to diagnostic rad?
coherent
217
Bio factors that affect radiosensitivity? (5)
oxygen, age, recovery, chem. agent, hormesis
218
what digests cell fragments (thru phagocytosis) aka "suicide bags"?
lysosomes
219
series of 3 consecutive nucleotide bases in the DNA --\> specifies which amino acid will be added next during protein synthesis
codon
220
What happens to the differential absorption of Compton interactions as tissue Z increases?
no change (Compton interactions are independent of Z)
221
what N bases make up pyrimidines?
thymine & cytosine
222
Name a wide angle scatter
Compton effect
223
an uncharged mol. that contains a single unpaired e- in the outer shell
free radical
224
dose delivered over a period of time at equal intervals at the same dose rate is called?
fractionation
225
which XR interaction involves the incident photon interacting w an outer shell e- & uses only part of its energy to eject an e- from the atom?
Compton Effect
226
macromolecules break down into smaller units (H2O & CO2 are end products)
catabolism
