Term
Which part of the cell cycle is the most sensitive, most resistant, and has intermediate sensitivity
M, late S, G1, Early S, G2 |
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Definition
Most sensitive is Late G2 and M
Intermediate is Early S and G1
Most resistant is Late S |
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Term
| About how fast is energy deposited into organic matter |
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Definition
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Term
| What 3 factors are meant by the "Interaction of radiation in cells being a probabillity function. |
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Definition
Matter of chance
may or may not interact
may or may not produce damage |
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Term
| Give three generalizations about Radiobiology |
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Definition
Nonselective
Visible changes are not unique
biologic changes occur after a latent period |
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Term
| What two types of actions occur on a cellular level with Ionizing Radiation |
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Definition
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Term
| Describe Ionizing radiations direct action with biological matter |
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Definition
Deposits energy in the critical target and ionizes or excites it, and produces damage by direct ionization.
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Term
| Can Direct Interactions be chemically altered |
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Definition
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Term
| What type of radiation are direct interctions more likely to occur with |
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Definition
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Term
| Describe Indirect actions of ionizing radiation, |
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Definition
| Indirect action involves breaking apart of the water molecules in the cells into ions creating the possibility of free radicals |
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Term
| How much of the cell is made up of water |
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Definition
|
|
Term
|
Definition
| contains a single unpaired electron in the outer shell |
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Term
| How does the radiolysis of water become a free radical |
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Definition
The interaction produces and ion pair (HOH+ + e-) and the free electron is captured by another water molecule
(HOH-), HOH+ and HOH- dissociate into H+ + OH*and
OH- + H* |
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Term
| What are the effecs of free radicals based on |
|
Definition
| Thier capability to initiate chemical reactions |
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Term
| What is the major contributor to indirect cell damage. |
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Definition
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Term
| Why is there a greater probability of damage caused by an indirect action |
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Definition
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|
Term
| What 3 factors does radiation energy transfer depend on |
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Definition
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Term
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Definition
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|
Term
| What 3 things do we use to determine how radiation energy is transfered |
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Definition
Linear energy transfer
Relative biologic effectiveness
Oxygen enhancement ratio |
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|
Term
What is LET
How is it expressed
It is a function of ____ and _____ |
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Definition
Rate at which energy is deposited charged particle from different types of radiation travels through matter
KeV/ Micron
Funtion of mass and charge |
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|
Term
| What is Low Let Radiation |
|
Definition
ionizations are distant from each other
Does not give up all energy quickly
Usually causes damage through indirect action
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|
Term
| Why does Low LET cause mostly indirect damage |
|
Definition
|
|
Term
| What are examples of LOW LET radiation |
|
Definition
| x rays , gamma rays , electromagnetic radiation |
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|
Term
| What is High LET Radiation |
|
Definition
Particles that have a substantial mass and charge
Cause dense ionizations along thier track
Lose energy more quickly
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|
|
Term
| What are some examples of HIGH LET Radiation |
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Definition
| Alpha particles, neutrons, ions of heavy nuclei |
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|
Term
| To what degree and types of biologic responses are associated with the different types of LET Radiation |
|
Definition
| Different LET radiation produce different degrees of the same biologic response |
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Term
|
Definition
| relates the ability of radiation with different LETs to produce a specific response |
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|
Term
|
Definition
| RBE = to dose in Gy from 250kVp xrays / dose in Gy of test radiation |
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|
Term
| What relates the ability of radiations with different LETs to produce a specific biologic response |
|
Definition
| Relative biologic effectiveness |
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Term
| Why is RBE alone not effective for use in radiation dose level for humans - what is needed |
|
Definition
RBE is used in experiments with animal tissues, a weighting factor (Wr) is neededto calculate EqD
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Term
| What is oxygen enhancement ratio and how is it expressed |
|
Definition
ratio of radiation dose required to cause a particular bilogical response in an a-noxic enviornment to to one with oxygen.
OER= rad dose causes a response without O2 / dose that causes a response with O2 |
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|
Term
| What type of Radiation is not affected by OER and why |
|
Definition
| High LET because it produces its bilologic effects by direct action. |
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|
Term
| Which type of LET is more destructive to biologic matter |
|
Definition
|
|
Term
| What type of radiation would produce a OER near 1 |
|
Definition
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|
Term
| Which part of the cell is the most likely part for radiation damage |
|
Definition
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|
Term
| What are the four categories of DNA damage |
|
Definition
Base
single strand
double strand
crosslinks |
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|
Term
| What is it called when an altered cell no longer has the same genetic sequence |
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Definition
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|
Term
| Which part of the DNA molecule is affected in a single strand break |
|
Definition
| One strand of the sugar phosphate rails |
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|
Term
|
Definition
| When one of the sugar phosphate bonds is broken, at one point in the sugar phophate rail |
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|
Term
| What type of LET is most responsible for point mutations |
|
Definition
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|
Term
| What type of LET radiation is more responsible for double strand breaks |
|
Definition
|
|
Term
| Correlations with _____ radiation and, _____ breaks end with more results in cell death |
|
Definition
| High LET , double stranded |
|
|
Term
| what type of Radiation Energies cause a direct covalent cross link break |
|
Definition
|
|
Term
| What can reult from a double strand same rung break |
|
Definition
| genetic material is divided causing impaired function or cell death |
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|
Term
| Name three types of crosslink damage and what they are |
|
Definition
Covalent - DNA Links to a protein
Intrastrand- 2 regions of same DNA Strand
Interstrand - Between 2 complimentary DNA Strands or Different DNA Molecules |
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|
Term
| What type of cells can chromosome breaks occur in |
|
Definition
|
|
Term
| Can breaks be transmitted during mitosis and meiosis |
|
Definition
|
|
Term
| What are three names for gross structural changes in chromosome resulting from irradiation |
|
Definition
| Abberation, Anomaly, Lesion |
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|
Term
| When is chromosome abberation inflicted, also after what part of the cell cycle |
|
Definition
| Early interphase - Before DNA Synthesis takes place, so before S phase (when DNA is duplicated) |
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|
Term
| When is chromatid abberation take place in the cell cycle |
|
Definition
| Late interphase after DNA synthesis has taken place (G2 or Mitosis, Prophase or Metaphase) |
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|
Term
| What will happen to the daughter cells if damage is done to a chromosome |
|
Definition
| Both daughter cells with have damage |
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|
Term
| What percentage of the time do broken ends of chromosome rejoin and restitute |
|
Definition
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