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morerbwrksheets
more radiobio worksheets from casey
Question | Answer |
---|---|
This can be seen in karyotyping | Main chain |
Crosslinking | Sticky spurs |
Point lesions | Messes with chemical bonds of DNA not visible in karyotyping |
Dicentric | 2 centromeres |
Accentric | No centromeres |
If two acentric fragments do not find anywhere to go and come together what happens | There is a loss of genetic information(this is the most common occurance) |
Ring chromosome | Don’t have ends so attaches to itself this causes death of the chromosome and the more you have the higher the chance of cell death |
Radiation effects are | Non-specific |
Direct hit | High LET radiations |
X ray damage is caused by __________ness | Randomness it does not go after a particular area of cell |
Radiolysis | The interaction of water with radiation |
90 to 95 percent of human interaction is with | water, indirect |
Multi target multi hit | apply to human cells, more than one target |
Single target single hit | Applies to enzymes, viruses, and simple cells such as bacteria |
D37 mean | The measure of the radiosensitivity of biologic tissue |
Low D37= | High sensitivity (radiosenstive) |
High D37= | Low sensitivity (radioresistant) |
Do means | Lethal dose |
Large Do = | Radioresistant cells takes a high dose to kill |
Small Do= | Radiosensitive cells |
DQ | Threshold dose |
The wider the shoulder the | more recoverability |
The smaller the shoulder the | Less chance of recovery |
Cell cycle time takes | 24 hours |
How long it takes is determined by | G1 phase |
High LET is more damaging than | low LET |
Different types of ionizing radiation have different | LET |
The efficiency for producing a given response is related to | Linear Energy transfer |
Part of the law of b and t | stem cells are radiosensitive |
The law of b and t states that | Radiosensitivity increases with proliferation rate |
The response of tissue to radiation is principally a function of | dose |
The RBE | Is a descriptor of the type of radiation |
The law of b and t relates to | radiosensitivity and cellular differentiation |
This is higher for high LET radiation than for low LET radiation | RBE |
How is LET measured | KeV/Um |
This has a high LET | Alpha particles |
The maximum value of RBE is | 3 |
Dose fractionation is less effective than a single dose because | Recovery, occurs between doses |
The OER | Is highest for low LET radiation |
LET is useful for expressing radiation | Quality |
What is related to radiation protection as LET is related to radiobiology | Radiation weighting factor (WR) quality factor |
This has low LET | Cobalt 60 gamma rays |
Dose protraction relates principally to | Dose rate |
Considered a physical dose-modifying factor | Dose protraction |
Considered a biological dose modifying factor | The oxygen effect |
Dose fractionation is less effective than an equal single dose because of | Cellular recovery |
Why do we develop radiation dose-response relationships | To predict the harmful effects of radiation after an accident |
Radiation induced damage in tissue | Is greater in the presence of oxygen |
When one considers the biologic modifying factors to a radiation response | Age is a factor and sex is a factor |
Why is a linear,nonthreshold dose response relationship used as a model for radiation protection guides | Because in a nonthreshold dose relationship, any dose is expected to produce a response |
The least sensitive time in life to radiation exposure is | There is no least sensitive time |
Exhibits a threshold type of radiation dose-response relationship | Cataracts |
When a radiation dose-response relationship intercepts the response axis at a positive value | That response is not related to radiation |
follows a nonlinear, threshold type of dose-response relationship | Death |
dose limits (DLs) are based on this type of radiation dose-response relationship | Linear, nonthreshold |
the late effects of diagnostic x rays probably follow which type of radiation dose-response relationship | Linear, nonthreshold |
a wide error bar on a graphic data point indicates what | Little confidence |
this factor has no influence on response to radiation exposure | Occupation |
these do have an influence on the response to radiation exposure | Age, dose protraction, oxygen tension, and sex |
humans are most sensitive to radiation | In utero |
when an irradiated cell dies before the next mitosis, this is called | Interphase death |
a linear, nonthreshold dose response relationship | Suggest that even the smallest dose may be risky |
when a linear, nonthreshold dose response relationship intersects the response axis at zero dose, this means that | There is a natural incidence of the response |
the genetically significant dose (GSD) | Depends on the average gonadal dose for various procedures |
RBE | 1 and max is 3 |
LET of diag x ray is | 3 kev/m |
Radiation effects at the total body occur because of | radiation damage to cells |
Cellular damage occurs because of | molecular responses to radiation |
DQ is the | Threshold dose or shoulder dose |
If undifferentiated cells are irradiated in vivo | Such cells are sensitive to radiation |
Phase of the cell cycle that is considered most resistant | Late S phase |
When cell survival curves are used, the measure of cell radiosensitivity is | DO |
When irradiated with high LET radiation, human cells follow which of the following models | The multitarget, single hit model |
The probability of human cell death can be computed | Using the poisson distribution |
If a dose equal to D37 were uniformly distributed, what percentage of cells would survive | 0% |
Means mean lethal dose | DO |
The multitarget, single hit model | Presumes a threshold |
The difference in generation time among different types of cells is due mainly to the length of | the G1 phase |
Does not affect the radiation response of mammalian cells | Sex of cell |
Does affect the radiation response of mammalian cells | Dose rate, LET, presence of oxygen, stage of the cell in its cycle |
In a cellular radiobiology | Single cells are allowed to grow into colonies |
According to the multitarget model of cell lethality | Cells have more than one critical target, each of which has to be inactivated for cell death |
According to target theory | Radiation interacts randomly |
When irradiated with x-rays, human cells follow | the multitarget, single hit model |
To explain radiation effects on living cells, target theory states that | A target can receive a hit by direct or indirect effect |
If a dose equal to D37 were randomly distributed what percentage of cells would die | 63% |
Of the various macromolecules that are sensitive to radiation, the most sensitive is | DNA |
Usually, radiation interacts with DNA | Indirectly |
Free radical ions are associated with biologic injury induced by what type of radiation | Diagnostic s rays |
A reactive atom or molecule that has an unpaired electron in its outer shell is called | Free radical |
The genetic code of DNA | Is transcribed by mRNA |
If an affect of radiation on molecular DNA | Cross-linking |
After a low radiation dose, most cellular radiation damage that results in a late total body effect occurs because of | Point lesions |
The biologically reactive molecular byproducts formed during radiolysis of water are thought to be | H* and OH* |
Radiation may interfere with DNA synthesis by | The G1 effect, which is the failure to commence DNA synthesis because of damage that occurs during the G1 period |
May occur in DNA molecules as a result of irradiation | A double strand break |
When water is irradiated products of the initial interaction are | OHO+ and e- |
Example of anabolism | Protein synthesis |
Radiation induced changes in DNA that result in genetic damage follow which type of dose response relationship | Linear non threshold |
This is a free radical | HO2 |
When molecules are irradiated | In suspension, they are irradiated in solution |
Radiation effects at the total body level occur mainly because of | Indirect effect |
Hydrogen ion | H+ |
Hydroxyl free radical | OH* |
Positively charged water | H2O+ |
Hydroxyl ion | OH- |
Hydrogen free radical | H* |