Exam 1 - 5. Radiation Biology Flashcards
3
Radiographs are made with _____ radiation
3
Follow the ______ principle to minimize risks.
3
What does ALARA stand for?
4
Low energy X-rays are ______ by the body (_____absorption).
4
Low energy X-rays occur when X-rays interact with ____ tissues like ____ or _____. These low energy x-rays are _____.
4
High energy X-rays undergo _____. This releases ________ electrons which cause ______ when interacting with _________.
4
What is the major site of biologic damage?
5
In direct actions, the photon directly interacts with and ionizes a _______. The ________ produced by the ionization interaction (________) may also interact directly with biologic macromolecules.
5
What fraction of radiation is direct action?
5
Indirect action, the secondary electron interacts with, for example, a _____ to produce a ______, which in turn produces the _______.
5
What fraction of radiation is indirect radiation?
6
Direct and indirect radiation both yield ________, which are ________.
6
Free radicals are ______ reactive and have ______ half lives.
6
Free radicals play a dominant role in producing _______ in _______.
7
In direct action, free radical generation occurs within _____ of the passage of a photon
7
Free radicals quickly reform into _______.
7
What would be an example of free radical dissociation using an equation?
7
What would be an example of free radical cross-linking using an equation?
7
Direct actions dominate with ______) radiations and are less predominant with _____ radiations such as ______.
8
Water constitutes approximately ___% of mammalian cells.
8
When water is irradiated, it _____ into _____. This is referred to as _____.
8
The initial series of interactions of x-ray photon with water produce _____ and _______ free radicals that interact with biologic macromolecules
8
The hydroxyl radical is _____ and is estimated to cause ______ of the biologic damage to mammalian cells from x-rays.
9
Indirect action results in _____ damage.
10
What is the range of time for energy absorbed in radiation biology Excitation and ionization? Chemical reactions? Bioeffects?
11
What is the term for the time between when energy is absorbed and damage done to when the signs and symptoms are visible?
11
The latent period may take ____ or up to ____ or more.
11
How long the latent period takes depends on the ______ and the _______.
12
What are the two most important damages to DNA?
13
During what phase are the cells most sensitive to radiation?
14
During what phase of the cell cycle are cells less and LEAST sensitive to DNA damage?
13
If a DNA strand break occurs prior to chromosomal duplication (late G1/early S), the break is ______ and both sister chromatids will ______. These are known as _______.
13
If the DNA strand break occurs after chromosomal duplication (late S/G2), only ________ will encounter the break. These are known as ______.
14
Stochastic effects are caused by ______.
14
Deterministic effects are caused by ____.
14
Is there a minimum threshold dose for stochastic effects?
14
Is there a threshold dose for deterministic effects?
14
Describe the severity of clinical effects and dose for stochastic effects.
14
Describe the severity of clinical effects and dose for deterministic effects.
14
For stoachastic effects, the frequency of the effect is proportional to ____. The higher the dose, the _____ the risk of manifesting the disease.
14
For deterministic effects, the probability of effect is ____ of dose. Most individuals manifest the effect when the ______ is exceeded.
14
Are stochastic effects caused by doses used in diagnostic radiology?
14
Are deterministic effects caused by doses used in diagnostic radiology?
14
What is an example of stochastic effects?
14
What is an example of deterministic effects?
16
What is the term for damage to body cell and is passed on to the same type of cell in that person, not to future offspring?
17
What is the most likely result of stochastic effects?
20
Is the nucleus or the cytoplasm more sensitive for determinisitic effects?
20
____ in the chromosome is the most sensitive site for deterministic effects.
21
What is the term for damaged cells releasing molecules that kill adjacent cells?
22
The Law of Bergonie and Tribodeau states that radiosensitivity of a biological tissue is directly proprtional to the ______ and inversely proportional to the _______ of its cells.
22
Radiosensitivity is greatest for those cells that have a high _____ and a long _____, such as the ______ and _____ mucosa.
22
Radiosensitivity is greatest for cells that are differentiated or undifferentiated?
23
The most sensitive cells to deterministic effects are those that _____, are ____, and are ______.
23
_____ cells are most sensitive, followed by cells of ___, ___, ____, and _____.
24
The cells that are least sensitive to deterministic effects are _____ cells, followed by ___, ____, ____, and ____.
26
What does this describe?
-Acute radiation syndrome that causes nausea, vomitting, and diarrhea
-1-2 Gy
26
What does this describe?
-Acute radiation syndrome that damages the bone marrow, causing infection, bleeding, and anemia.
-2 to 7 Gy
26
What does this describe?
-Acute radiation syndrome that causes damage to libing of the GI tract, resulting in ulceration, septicemia, and death
-7-15 Gy
26
What does this describe?
-Acute radiation syndrome that causes death.
-greater than 50 Gy
27
Late effect of low doses: Somatic
Cataract formation has a threshold of ___ Gy and a dental dose of ____ to ____ mGy (____ times lower than the threshold).
28
Effects of low doses: fetal
-0-9 days
-most sensitive stage for lethal effects
28
What is the threshold for effect for preimplantation stage?
28
Effects of low dose: fetal
What is the stage that is 10 days to 8 weeks and causes mental retardation, microcephaly, growth retardation?
28
Effects of low doses: fetal
-8 weeks to 25 weeks
-causes mental retardation
28
Late fetal period: Excess absolute risk is about ____ Gy for early child cancer.
29
Fractionation is spreading the dose out over ___ or giving it in ____ to ___ the damage.
30
Smaller volume has what effect on cells damaged?
30
What effect does lower oxygen have on radiation? Why?
30
Higher Linear Energy Transfer (LET) = more ______
31
Fractionation of daily small doses of radiotherapy for the oral cavity provides _____ tumor destruction than with a large single dose.
31
What are the “4 R’s” for benefits of fractionation?
32
For radiotherapy of the oral cavity, typically ____ Gy is administered for a weekly exposure of ____ Gy. The radiotherapy continues for ____ weeks until a total of ____ Gy is administered. In recent years, a new 3D technique called ______ has been used to control the dose distribution.
33
What is the “Golden Window” for effects of therapeutic radiation on the oral cavity?
33
The highest risk for effects of therapeutic radiation on the oral cavity is between ____ months after therapy.
35
At doses of 60 Gy and greater, the fraction for Xerostomia to occur increases to ____.
36
What are the three types of radiation caries?
37
Therapeutic radiation does not affect ______ teeth, but may effect _____.
38
At what Gy are stimulatory effects on osteoblasts seen?
38
At what Gy is there death of chondroblasts and osteoblasts?
38
At what Gy is a single dose in a young child that results in irreversible growth retardation and short stature?
38
At what Gy is there radiation damage to mature, intact bone, a more radioresistant tisue?
38
Osteoradionecrosis is a combination of what three things?
39
If the muscles of mastication are involved in radiation effects, _____ may result. The ___ and _____ muscles are usually invovled.
