Ch 33 Deterministic Effects Flashcards
1
Q
There have been no reported cases of death after exposures to…
A
Diagnostic Radiation
2
Q
Early pioneers died from _________ effects of x-ray exposure
A
Stochastic
3
Q
What was Chernobyl?
A
- Nuclear reactor accident in 1986
- 30 people experienced ARS and died
4
Q
What was the 3 mile island?
A
-Partial core meltdown in 1979
-No one died or was seriously
injured
5
Q
Is employment in the nuclear power industry safe?
A
Yes
6
Q
When do symptoms from the Prodromal period begin?
A
Within hours of exposure and
continue for up to 1-2 days
7
Q
What are early symptoms of the Prodromal period?
A
- Nausea
- Vomiting
- Diarrhea
- Leukopenia (decreased white blood cell count)
8
Q
What is the manifest illness?
A
Onset of symptoms after the latent period
9
Q
What are the (3) types of Manifest illness’?
A
- Hematologic
- Gastrointestinal
- Central Nervous System
10
Q
What dose of radiation produces the GI Syndrome?
A
1,000-5,000 rad (10-50gy)
11
Q
When do prodromal symptoms for the GI Syndrome occur?
A
Within hours of exposure
12
Q
How long is the latent period for the GI Syndrome?
A
3-5 days
13
Q
What are symptoms of the manifest period for the GI Syndrome?
A
- Nausea, vomiting, diarrhea, loss of appetite, lethargy
- Diarrhea persists and becomes more severe leading to watery and bloody stools
14
Q
When does death occur for the GI syndrome?
A
4-10 days
Due to severe damage to intestinal cells (dehydration of cells)
15
Q
What happens to the electrolyte balance during GI syndrome?
A
It is destroyed
16
Q
What are the most sensitive cells in the body?
A
Stem cells
17
Q
What does LD stand for?
A
Lethal Dose
18
Q
What does LD 50/60 mean?
A
Lethal dose of 50% of the people in 60 days
19
Q
Acute radiation lethality follows a…
A
Nonlinear threshold dose response relationship
20
Q
With medical support, how much radiation can humans tolerate?
A
350-850
21
Q
What is considered a lethal dose of radiation?
A
350 rad (3.5gy)
22
Q
How is Acute Radiation lethality measured?
A
LD 50/60 350
23
Q
What can cell death cause?
A
Impaired organ or tissue function
24
Q
What organs/ tissue, can be effected by partial body radiation?
A
Every organ and tissue
25
What determines the level of tissue response?
Depends on intrinsic radiosensitivity and the kinetics of cell proliferation and maturation
26
What are the local tissues that are immediately affected by radiation exposure?
Skin, gonads, and bone marrow
27
All early radiation responses follow a...
Threshold type dose response type relationship
28
What is a Threshold type dose response relationship
- A minimum dose is needed to produce a response
| - Once the minimum dose is exceeded the severity of response increases with increasing dose
29
Define
| Erythema-
Sunburn like redding of the skin
30
What is the 1st observed biologic response to radiation?
Erythema
31
Define
| Desquamation-
- Ulceration and denudation of the skin
| - Shedding of outer layer of skin
32
How long will it take for someone to show erythema?
10-30 mins of radiation exposure
33
Define
| Epilation-
Loss of hair
34
Responses to doses as low as _____ have been observed in the gonads.
10 rad (100mGy)
35
Human gonads are very sensitive to radiation. T/F
True
36
What are the male gonads
Cells of the Testes
37
Why do gonads respond differently to radiation when compared to other cells?
Because of the progression from the stem cell to the mature cell
38
What are the female gonads?
Cells of the Ovaries
39
What is the most radiosensitive (vulnerable) phase in male cell maturation?
Spermatogenia
40
What is the most radiosensitive (vulnerable) phase in female cell maturation?
Mature Follicle
41
What is the stem cell in males?
Spermatogonia
42
What is the stem cell in females?
Oogonia
43
How many ova are available for fertilization over lifetime?
400-500
44
What is a female's mature germ cell called?
Ovum (egg)
45
When are female mature germ cells (ovum) produced?
At puberty
46
How often are male germ cells produced?
Continuously
47
What is a males mature germ cell called?
Spermatozoa (sperm)
48
How long does it take for the male germ cell to mature?
3-5 weeks
49
When do female stem cells develop?
During fetal life
50
Irradiation to the ovaries early in life reduces their ______ through germ cell death
Size (atrophy)
51
When is radio sensitivity it's highest?
During fetal life and early childhood
52
When is radio sensitivity it's lowest?
20-30 y/o
53
When does radio sensitivity pick back up?
After age 30
54
```
Effects of dose on the ovaries:
10 rad (100 mGyt)
```
Delay or suppression of menstruation
55
```
Effects of dose on ovaries:
200 rad (2 Gyt)
```
Temporary infertility
56
```
Effects of dose on ovaries:
500 rad (5 Gyt)
```
Permanent sterility
57
Effects of dose on ovaries:
| 200-500 rad (2-5 Gyt)
Genetic mutations
58
When does atrophy occur to the testes?
After high doses of radiation
59
The spermatogonial stem cells are the most ____________.
Radiosensitive
60
When is sperm cell count affected by radiation?
Several weeks after exposure
61
Other than spermatogonial stem cells, how does radiation effect other cells in the development phase?
They are mostly radioresistant
62
```
Effects of dose on testes:
10 rad (100 mGy t)
```
Reduction in number of sperm
63
```
Effects of dose on testes:
200 rad (2 Gyt)
```
Temporary infertility (starts 2 months after irratiation and lasts up to 12 mths)
64
```
Effects of dose on testes:
500 rad (5 Gyt)
```
Permanent sterility
65
What does the hemopoietic system consist of?
- Bone marrow
- Circulating blood
- Lymphoid tissue
66
Where are most blood cells manufactured?
In the bone marrow
67
Where do cells of the hemopoietic system develop from?
A pluripotential stem cell
68
What are the first cells to be affected by radiation exposure?
Lymphocytes
69
___________ experiences a rapid rise, then rapidly decrease
Granulocytes
70
How long does recovery of granulocytes take?
Approximately 2 months
71
When do Lymphocytes begin to reduce in number after radiation exposure?
Within minutes or hours of exposure, slow to recover
72
What are the least sensitive of blood cells?
Erythrocytes
73
How long does it take for Erythrocytes to recover?
6-12 mths
74
Do Thrombocytes deplete slowly or quickly?
Slowly, recovery takes about 2 months
75
What is Cytogenetics?
The study of the genetics of cells, particularly the cell chromosomes
76
How many types of chromosome aberrations can be radiation induced?
Nearly all of them
77
Human peripheral ___________ are used for cytogenetic analysis.
Lymphocytes
78
When does chromosome damage occur?
- At the time of radiation
| - May not be measured for months or years after irradiation
79
Cytogenetic Effects of Radiation follows a...
Non threshold dose response relationship
80
What is a Karotype?
Chromosome map
81
Each cell consists of:
- 22 paris of autosomes
| - 1 pair of sex chromosomes
82
What does a DNA hit produce?
Disruption of the molecular structure
83
What does a chromosome hit produce?
Visible derangement of the chromosome
84
What is more severe, a chromosome hit or a DNA hit?
Chromosome (chromosomes contain DNA)
85
Single hit chromosome aberrations are produced with a...
Linear, non threshold dose response relationship
86
Multi hit chromosome aberrations are produced with a...
Non linear, non threshold dose response relationship
87
Are diagnostic x-ray beams intense enough or large enough to cause death?
No
88
What type of exposure does Hematologic, GI, and CNS Syndrome all require?
Whole body exposure
89
What is ARS (Acute Radiation Syndrome?)
Sequence of events that follow high level radiation exposure leading to death within days or weeks
90
What are the (3) stages of ARS (Acute Radiation Syndrome?)
1. Prodromal Period
2. Latent Period
3. Manifest Illness
91
What is the Latent Period?
- Time after the exposure
| - No signs/ symptoms of radiation sickness
92
How long does the Latent Period last?
- Hours to weeks
| - The higher the dose, the shorter the latent period
93
What period may mislead one to think recovery has occurred?
Latent period
94
What is produced by radiation doses of 200-1,000 rad
Hematologic Syndrome
95
What is characterized by a reduction in white blood cells, red blood cells, and platelets?
Hematologic Syndrome
96
What is produced by radiation doses greater than 5,000 rad?
Central Nervous System (CNS Syndrome)
97
During the CNS syndrome, when do the prodromal symptoms occur?
Within minutes
98
During the prodromal period, what dose will begin producing violent symptoms?
1,000 rad (Gy t)
99
At higher doses it is difficult to separate the ___________ syndrome from the __________ illness.
Prodromal/ Manifest
100
At low doses, there may be no ________ period.
Prodromal
101
At high doses, the latent period may ________.
Disappear
102
What is the name for the immediate response of radiation sickness?
Prodromal Period
103
How severe are the prodromal symptoms during the Hematologic Syndrome?
Mild
104
What does the manifest illness consist of during a non lethal dose of Hematologic Syndrome?
- Vomiting
- Mild Diarrhea
- Malaise
- Lethargy
- Fever
105
If dose is not lethal during the Hematologic Syndrome, when does recovery begin?
2-4 weeks, can last up to 6 months
106
During the Hematologic Syndrome, what happens if the dose is lethal?
- Reduction in blood cells (defense against infection)
- Hemorrhage and dehydration
- Death due to infection, electrolyte imbalance, and dehydration
107
When do prodromal symptoms occur during the CNS Syndrome?
Within minutes of exposure
108
How long does the latent period last during the CNS syndrome
Up to 12 hours
109
During the CNS Syndrome what are the Manifest illnesses?
- Disorientation
- Loss of muscle coordination,
- Difficulty breathing,
- Seizures
- Loss of equilibrium
- Ataxia
- Lethargy
110
What does ataxia mean?
Inability to coordinate muscles
111
During the CNS syndrome, what is the end result of the manifest illness?
- Death within days
- Pt lapses into coma and dies
- Ultimate cause of death is elevated fluid in the brain.
112
What is the mean survival time?
As whole body radiation dose increases, the average time between exposure and death decreases
113
When radiation dose increases from 200-1,000 rad, mean survival time decreases from _____ to ____ days
60/ 4
114
What is the mean survival time of Hematologic Syndrome?
Varies with dose (60-4 days)
115
What is the mean survival time of GI Syndrome?
Relatively consistent at 4 days
116
What is he mean survival time of the CNS syndrome?
Varies with dose (3 days to hours)
117
What cell layers of the skin participate in the response to radiation exposure?
All of them
118
At what rate are skin cells replaced?
2% per day
119
What are the most vulnerable skin cells?
Basal cells
120
Describe Basal cells:
- Most vulnerable to radiation
- Lowest layer of the outer skin layer
- Stem cells that mature into the cells of the epidermis
- Most radiosensitive
121
Skin effects follow a...
Non linear, threshold dose response relationship
122
What does SED mean?
Skin Erythema Dose
123
What is SED (Skin Erythema Dose?)
- Dose of radiation that causes erythema
- SED 50 is about 500 rad (Gy 1)
* Dose required to affect 50% irradiated
