Final Flashcards

(79 cards)

1
Q

Helps determine structure’s radiation tolerance

A

Alpha beta ratio (a/B)

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2
Q

Radiosensitivity of cells/nonrepairable

A

Alpha (a)

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3
Q

Repairable portion of radiation damage

A

Beta (B)

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4
Q

Larger B = _______ ratio = _______ repair and _______ shoulder

A

Small
Increase
Broad

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5
Q

Law stating that ionizing radiation is more effective against cells that are actively mitotic, undifferentiated, and have a long mitotic future

A

Law of Bergonie and Tribondeau (B&T)

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6
Q

Mature/well differentiated cells with less division/mitotic activity (A) = _______ radioresistant

A

More

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7
Q

Sensitivity of cells is ______ proportional to mitotic A and _______ proportional to differentiation

A

Directly, inversely

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8
Q

Environmental conditions can affect radiosensitivity, especially if stressed

A

Law of Ancel and Vitemberger

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9
Q

2 parts that affect the Law of Ancel and Vitemberger

A

Biological stressor on cells
Environment: in poor environment (less oxygen) cells have more time to repair because they’re less likely to move into mitosis (M)

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10
Q

What is the biologic stressor on cells?

A

Mitotic A/division

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11
Q

Cells that divide _______ damage earlier

A

Quickly

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12
Q

3 cell populations

A

Stem cell
Transit
Static cell

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13
Q

Cells that provide/divide for its and other populations, undifferentiated

A

Stem cell

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14
Q

2 examples of stem cells

A

Basal cells

Bone marrow

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15
Q

Cells that go from one place to another, may or may not divide; red blood cells (RBCs)

A

Transit cell

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16
Q

Fully differentiated and mature cells, no or limited mitotic A

A

Static cell

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17
Q

2 examples of mitotic cells

A

Adult nervous tissue

Muscle

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18
Q

5 cell population categories

A
Vegetative intermitotic cells (VIM)
Differentiating intermitotic cells (DIM)
Multipotential connective tissue cells
Reverting postmitotic cells (RPM)
Fixed postmitotic cells (FPM)
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19
Q

Most radiosensitive cell population, rapidly dividing undifferentiated with short life spans

A

Vegetative intermitotic cells (VIM)

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20
Q

___% of VIM undifferentiated, ___% mature leukocytes

A

95%, 5%

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21
Q

3 examples of VIM

A

Basal cells
Crypt cells of intestines
Erythroblasts

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22
Q

Immature RBCs

A

Erythroblasts

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23
Q

Second most radiosensitive cell population, actively mitotic but more differentiated; more specialized

A

Differentiating intermitotic cells (DIM)

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24
Q

4 examples of DIM

A

Type B spermatogonia
Urinary bladder
Lens of eye
Mucous membranes of of lung

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25
Intermediate/moderate radiosensitivity cell population | Divide irregularly and are more differentiated than VIM and DIM cells
Multipotential connective tissue cells
26
2 examples of multipotential connective tissue cells
Endothelial cells | Fibroblasts
27
Cells of the cavity of the heart and vessels
Endothelial cells
28
Cell in connective tissue that produces collagen and other fiberes
Fibroblasts
29
Cell population doesn't divide normally unless stimulated, live longer and are more differentiated than other groups Radioresistant
Reverting postmitotic cells (RPM)
30
3 examples of RPM
Liver cells Mononuclear cells in blood and lymph Mature lymphocytes
31
Most radioresistant cell population, don't divide and highly differentiated; may or may not be replaced when they die Long living mature cells
Fixed postmitotic cells (FPM)
32
2 tissue organizations
Parenchyma | Stroma
33
Contains characteristics of cells of that organ, functional unit of cell; VIM, DIM, RPM, and FDM
Parenchyma
34
Connective tissue and vasculature intermediate radiosensitivity Supporting structures; blood vessel, nerves, etc.
Stroma
35
Function of tissues' most sensitive cell it contains
Radiosensitivity
36
Lethal dose that kills 50% of population in 60 days
LD50/60
37
3 modifying tissue responses
Physical factors Chemical factors Biological factors
38
High LET curves _______, no _______; cells show quick response, linear
Steeper, shoulder
39
HDR produce more damage, _______ shoulder on LDR graph
Broad
40
Rate at which radiation is delivered
Dose rate
41
_______ LET and LDR allow cells to repair
Low
42
2 chemical factors
Sensitizers | Protectors
43
Enhance killing effect of radiation, used to make tumor cells more sensitive Best known ex: molecular oxygen Must be in cell environment at time of exposure Oxygen must be 0-20 mm of mercury, over 20 has no effect
Sensitizers
44
Decreases cellular response
Protectors
45
Dose _______ with oxygen
Decreases
46
Low LET oxygen = _______ radiosensitivity 2-3 times = shoulder gets _______/_____ broad = _______ Do
Increases Smaller Less Decrease
47
Magnitude of oxygen effect, compares response with radiation without the presence of oxygen More pronounced with low LET because whether or not oxygen is present with high LET (average = 1.2-1.7) there's no healing
Oxygen enhancement ratio (OER)
48
OER for mammalian cells
2-3
49
OER formula
OER = dose without oxygen/dose with oxygen > 1 gives same biologic effect
50
Chemicals that protect normal cells from effects of radiation Act as free radicals that compete with oxygen in body Ex: sulfhydryls (1.5-2) contain free sulfur atom in their structure Present during exposure Used to protect esophagus, parotids and military; give 15-20 mL before radiation
``` Dose reduction factor (DRF) Protection factor (PF) ```
51
DRF/PF formula
DRF/PRF = dose with protector/dose without protector
52
2 problems with DRF/PFs
Amount needed to protect from whole body exposure usually lethal Decreases blood pressure (BP)
53
4 biologic factors
Position in cell cycle to phase in cell cycle Intracellular repair Age: very young and old more sensitive Sex
54
Synthesis (S) phase more _______, G2-M most _______, and G1 ______
Resistant Sensitive Moderate
55
Cells can repair _______ damage, _______ don't repair as well
Sublethal | Hypoxic
56
2 factors intracellular repair takes in
LET | Extrapolation/n number
57
3 reasons females are 5-10% more resistant to radiation than males
Nutrition Lipid/fat count greater Work environment
58
Dose of permanent sterility
15-20 Gy
59
Most sensitive trimester
First, 1-3 months
60
Why are younger patients more sensitive to radiation?
Less differentiated cells
61
4 stages to radiation syndromes
Prodromal Latent Manifest Recovery or death depending on dose and radiation type
62
Symptoms correlate to dose and can be gastrointestinal, neurologic, or both
Prodromal
63
Period in which victim appears to have no symptoms
Latent
64
Effects of exposure return typically worse than before correlated with dose
Manifest
65
3 radiation syndromes
Hematopoietic syndrome/bone marrow syndrome GI CNS
66
Syndrome at 1-10 Gy that affects blood, females more resistant 4-6 weeks 3-5 Gy = death
Hematopoietic syndrome/bone marrow syndrome
67
Survival and death dose for hematopoietic syndrome
``` Survival = under 2 Gy Death = over 10 Gy ```
68
At 100-1000 Gy; nausea and vomiting within hours lasts two days
Hematopoietic prodromal stage
69
Bone marrow and stem cells dying, blood counts decrease in a few days to 3 weeks
Hematopoietic latent stage
70
Anemia and serious infection 3-5 weeks after exposure
Hematopoietic manifest stage
71
2 causes of death from hematopoietic syndrome
Hemorrhage | Infection
72
Loss of crypt cells in small intestine at 1,000-10,000 cGy Death by bone marrow loss leads to infection, dehydration, and electrolyte imbalance 100% mortality rate without medical support; average survival = 3-10 days, 2 weeks with medical support Latent period 2-10 days after prodromal or absent
GI syndrome
73
GI syndrome threshold
10-50 Gy
74
Nausea, vomiting, cramps and diarrhea within hours
GI prodromal stage
75
Symptoms reappear after 5-10 days Severe diarrhea by 6th day leads to dehydration; bacteria enters blood stream and leads to sepsis Blood forming organs show severe radiation damage
GI manifest stage
76
Caused by gamma or neutrons, external whole body exposure at 20-50 Gy Death in several days Final stage Latent period several hours long Cause of death: intracranial pressure before other two syndromes Over 10,000 cGy
CNS syndrome
77
Rapid dehydration, lethargy, nervousness, confusion, severe nausea, vomiting, and burning sensation within minutes to hours
CNS prodromal stage
78
Coma and death in 5-6 hours, death 2-3 days past 50 Gy
CNS manifest stage
79
3 criteria for occurrence of total body radiation syndromes
Whole body exposure Exposure to gamma rays, neutrons, or x-ray externally; not isotopes Exposure must have occurred acutely, within minutes