Weekly quiz questions Flashcards by Meg-Georgia-Teague -

Are low (<0.01Gy/min) or higher dose rates (>1Gy/min) more effective at cell kill?

Higher dose rates are more effective at cell kill

How well did you know this?

Not at all

Perfectly

DNA damage is the biological effect of radiation for which level of study?

Molecular Level

How well did you know this?

Not at all

Perfectly

The inhibition of cell division is the biological effect of radiation for which level of study?

Cellular Level

How well did you know this?

Not at all

Perfectly

Death is the biological effect of radiation for which level of study?

Whole animal

How well did you know this?

Not at all

Perfectly

Genetic is the biological effect of radiation for which level of study?

Population

How well did you know this?

Not at all

Perfectly

What are the possible outcomes of cell damage due to radiation?

the cell might incorrectly repair itself (mutate/ modified cell)
Injured or damaged cells may repair themselves through the body’s defence mechanisms, resulting in no residual damage
The cell may die

How well did you know this?

Not at all

Perfectly

Lesions in the DNA occur at which phase?

chemical phase

How well did you know this?

Not at all

Perfectly

What are possible DNA damages that results from radiation?

base damage
intercalation
cross links
point lesions

How well did you know this?

Not at all

Perfectly

What are possible cell damages that result from radiation?

interruption of the cell’s food supply
membrane rupture
damage to lysosomes
damage to the nucleus and DNA

How well did you know this?

Not at all

Perfectly

What type of strand break occurs most often?

single

“the greatest amount of strand breaks in DNA is ____ strand breaks”

How well did you know this?

Not at all

Perfectly

Which form of oxygen are involved in the oxygen enhancement effect?

elemental oxygen within the cell

How well did you know this?

Not at all

Perfectly

Tumours which have areas of hypoxic cells and therefore more difficult to control with low LET ionising radiation are called?

radio resistant

How well did you know this?

Not at all

Perfectly

Which effect (indirect or direct) is the most important mechanism in causing damage from low LET radiation?

the indirect effect is the most important as it causes about 2/3 of the total damage

How well did you know this?

Not at all

Perfectly

Graphs of cell sensitivity versus phase of the cell cycle are called?

Age response curves

How well did you know this?

Not at all

Perfectly

The cell survival curve has several mathematical models which provide possible descriptions. One models assumes that each cell needs to be hit once only to cause reproductive death. This model is called?

single-sarge, single-hit model

How well did you know this?

Not at all

Perfectly

Three possible mathematical descriptions of the cell survival curve are?

single-target, single-hit model
Multitarget, single-hit model
the linear-quadratic model

How well did you know this?

Not at all

Perfectly

What is the effect that: when a free radical is formed within a cell and goes on to damage the DNA?

this is called the indirect effect

How well did you know this?

Not at all

Perfectly

Which deterministic effects following whole body irradiation is most likely to be successfully treated with antibiotics and/or bone marrow transplants?

Hematopoietic syndrome resulting from 3-8 Gy may be treated with antiobiotics and/or bone marrow transplants. Without such treatment death will occur in 3-8 weeks.

How well did you know this?

Not at all

Perfectly

What are the known causes for the reduction of the number of circulating blood cells in relation to the Haemotopoietic syndrome?

loss by haemorrhage

direct destruction of circulating white blood cells

How well did you know this?

Not at all

Perfectly

With the cerebrovascular syndrome, much higher doses are required to produce death when just the head is irradiation as opposed to a whole boy irradiation. True or False?

True

How well did you know this?

Not at all

Perfectly

Do deterministic effects have a threshold (i.e. are they observed with even the smallest of doses?)

There is a dose threshold for deterministic effects, below which no effect is observed.

How well did you know this?

Not at all

Perfectly

The phenomenon that radiation effects are less pronounced in some cells that have received a prior radiation dose is called?

Adaptive response

How well did you know this?

Not at all

Perfectly

According to ICRP60, which dose rates are most likely to cause permanent sterility in women?

a single dose of 2.5Gy

a prolonged dose of 0.2 Gy per year

How well did you know this?

Not at all

Perfectly

A group of cells is irradiated by shows no effect. Several generations later, effects do start to show up. This phenomenon is called?

Genomic instability

How well did you know this?

Not at all

Perfectly

What are the two known possible effects of the Gastrointestinal syndrome?

electrolyte imbalance | problems with absorption of metabolites

Which doses are most likely to cause permanent sterility in men according to ICRP60?

single dose of 3.5 Gy | prolonged dose of @ Gy per year

You have a dish full of cels and irradiation on half of the dish. You then observe that some of the cells in the unirradiated half behave as if they have been irradiated. This phenomenon is called?

The bystander effect

How can you treat Hematopoietic syndrome?

hematopoietic syndrom resulting from 3-8 Gy may be treated with antibiotics and/or bone marrow transplants

What is the adaptive response?

radiation effects are less pronounced in some cells that have received a prior radiation dose

What is genomic instability?

a group of cells is irradiated but shows no effect, until several generations later

What is the bystander effect?

half the non-irradiated cells behave as if they have been irradiated.

Regarding Watch Dial Painters, or Radium Girls, which three symptoms did they initially percent with?

teeth falling out tumours and fractures of the jaw anaemia

In the study of Japanese atomic bomb survivors, what were three reported early symptoms of radiation exposure?

vomiting hard loss bleeding from the gums

Why are doses from the Hiroshima atomic bomb more difficult to determine than the Nagasaki atomic bomb?

The bomb dropped on Hiroshima was a cannon type of bomb so the explosion was not symmetrical, whereas the Nagasaki bomb was an implosion device with a spherical explosion.

What were three means of exposure for early uranium miners?

external exposure by gamma rays exposure to short live radon gas and it's radioactive daughters inhalation of dust and it's long lived radionuclides

List two features of stochastic effects.

They show up as mutations | They are random in nature

Which three statements contribute to the debate about whether the Linear No Threshold model is correct?

- The LNT model is based on doses in the range of about 0.2Sv to 5Sv - Th doses received in medical imaging and by workers is much less than the actually measured so these workers can't be used in the estimates - To estimate risks for low doses (<100mSv), the information has to be extrapolated from higher doses, and the extrapolation has many uncertainties.

What is the total risk of death from exposure to ionising radiation (low dose/ low dose rate) for the general population (per million exposed to 10mSv)

The total risk for the general population is 500 per million exposed to 10mSv

Based on studies of Bohemian Uranium miners from the early 1900s, what is the risk estimate from lung cancer (per million people exposed to 10mSv)?

the risk is 85 per million exposed to 10mSv

Regarding stochastic effects, if you increase the radiation dose this will?

increase the probability that an effect will occur

What are the two objectives of radiant protection, in regards to deterministic and stochastic effects?

reduction of the probability of occurrence of stochastic effects prevention of determinist effects

Based on studies of atomic bomb survivors, Marshall Island nuclear testing survivors and radiotherapy patients, which are two known risk estimates for induction of thyroid cancer?

50-150 cases induced per million people exposed to 10mSv | 8 feathers per million exposed to 10mSv

What is the total risk of death from exposure to ionising radiation (low dose/ low dose rate) for radiation workers (per million people exposed to 10mSv)?

Fro radiation workers the risk is 400 per million exposed to 10mSv

Are radiation induced cancer indistinguishable from any other type of cancer?

yes, you can't distinguish between radiation and non-radiation induced cancers

Which studies contributes to our knowledge of stochastic effects?

studies of radiotherapy patients the lifespan study of atomic bomb survivors workers in uranium mining

Data measuring children of atomic bomb survivors show definite increases in the risk of congenital abnormalities, cancer, and chromosome aberrations. (true or false)

false | There are simply not the statistics to show that any of the named conditions in children of atomic bomb survivors

In the Megamouse experiment, the rate of induction of mutations varies by up to a factor of _______ between the 7 loci studied

here is a variation in mutation rates by a factor of 35 between the 7 loci studied, indicating that different gene loci have different radiosensitivy

What are three possible effects of radiation exposure during the organogenesis stage (10 days to 6 weeks)?

malformation of organs small head intrauterine growth retardation

In humans, what is the assumed safety period for the time between irradiation and conception (in months)

6 months

During the organogenesis stage of pregnancey (10 days to 6 weeks), what is the LD50/30 in Gy?

LD50/30 is 1.5Gy during organogenesis

What is the risk estimate for childhood cancer (under 10 years) for those exposed to radiation in-utero?

the risk is 200-250 per million exposed to 10mSv

What are two known possible effects of radiation exposure during the development of an embryo?

pre and neo-natal death | growth retardation

For protracted exposure, radiological life shortening is?

<1% per Sv

True or False? | The Megamous experiment has shown that at low dose rates, males are more sensitive to genetic damage than females..

True

What is the annual radiation dose (in mSv) you receive from internal radiation sources (i.e. the radioactive atoms inside your body)?

0.4mSv

According to the lecture slides, which value falls within the average range of annual occupational dose in Australia for radiotherapists (RT)?

0.7mSv | range of 0.5mSv to 1mSv

Which three industries have a higher fatality rate per million workers per year than radiation workers?

deep sea fishing construction coal mining

How many minutes canoeing gives the same (one in a million) risk of fatality as 20 uSv of radiation?

6 minutes

What is the average annual dose (in mSv) you receive from cosmic rays?

0.3

According to the lecture slides, what is the risk of contracting a fatal condition due to radiation exposure for the general public? (number per million per 10 mSV).

500

According to the lecture slides, which of the following is within the average range for the average annual occupational exposure for radiographers (MITs)?

0.15mSv

True or false? The magnitude of the oxygen enhancement effect is much less for high LET radiation such as alpha particles, than it is for low LET radiation such as x-rays.

True

The cell survival curve has several mathematical models which provide possible descriptions. One model assumes that there are two components to cell killing, one due to single event killing and one due to two event killing. This model is called:

linear quadratic model

In a group of cells, if 68 % are killed by a radiation dose in the presence of oxygen, and 36 % are killed by the same radiation dose but in a hypoxic environment, what is the oxygen enhancement ratio? (1 decimal place).

1.9 (68/36) (oxygen/hypoxic)

Which of the following processes are not a part of the biological phase?

apoptosis formation of radicals mitotic death carcinogenisis

"The number of _______ strand breaks in DNA correlates best with cell kill"

double

A whole body irradiation of 1000Gy, 100Gy, 10-100Gy and 2-10Gy, results in death after how many days?

1000Gy: immediate 100Gy: 1-2 days 10-100Gy: 3-10 days 2-10Gy: 10-60 days

"In relation to the Haematopoietic syndrome, recovery is possible for doses less than ____ Gy and with no medical support."

4Gy

With the Cerebrovascular syndrome, death appears to be a result of an elevated fluid content of the brain. (true or false)?

true

One aspect of studies of atomic bomb survivors is the study of those who were in-utero at the time of the exposure. In this study, mental retardation is most pronounced for what timeframe of exposure?

8-15 weeks after conception

What is the risk estimate for deaths due to bone cancer (the number per million people exposed to 10 mSv).

The risk estimate for fatal bone cancer is 5 per million people exposed to 10 mSv.

What are possible alternatives to the Linear No Threshold model for stochastic radiation effects?

threshold and hormetic relationship downwardly curving upwardly curving

What is the estimate of risk of fatal leukaemia from exposure to the bone marrow (give the number, per million people exposed to 10 mSv).

The best risk estimate for fatal leukaemia after exposure of the bone marrow is 50 per million people exposed to 10 mSv.

According to the linear no threshold model, at 0 Gy there is what chance that a person would develop a radiation induced cancer?

Based on studies of Bohemian Uranium miners from the early 1900s, what is the risk estimate for lung cancer (per million people exposed to 10 mSv).

85 per million exposed to 10 mSv.

What is the risk estimate for breast cancer cases per million people exposed to 10 mSv?

The risk estimate is 20 cases per million people exposed to 10 mSv.

What is the total risk of death from exposure to ionizing radiation (low dose/low dose rate) for radiation workers (per million people exposed to 10 mSv)?

400

What are three results of animal studies of the genetic effects of ionizing radiation?

Results of animal studies show that there is: no threshold there is a dose/effect relationship and there is no effect of fractionation

What is the doubling dose in man (in Gy)?

The doubling dose in man is 3 Gy

What is the risk estimate for childhood cancer (under 10 years) for those exposed to radiation in-utero?

The risk is 200-250 per million exposed to 10 mSv.

What is the likely threshold (in Gy) for mental retardation due to in-utero radiation exposure?

The likely threshold for mental retardation is about 0.2 Gy for in-utero radiation expousre (it is a deterministic effect).

During the pre-implantation stage of pregnancy (0-9 days after conception), the most significant risk from radiation exposure is:

Neo-natal death is the most significant risk during the pre-implantation stage of pregnancy.

For acute exposure, radiological life shortening is: (%??)

Radiological life shortening is of the order of 1-5% per Sv for acute exposure

According to the lecture slide, what is the average risk for contracting a fatal cancer due to occupational radiation exposure (the number per million per 10 mSV)?

The annual risk is 400/million.

A CT scan of the head is equivalent to how many years of normal background radiation?

It's equivalent to 1.4 years of normal background radiation.

Eating how many tablespoons of peanut butter gives you a one in a million chance of fatality?

How many days of normal background radiation gives the same radiation dose as a Chest PA x-ray?

What is the annual radiation dose (in mSv) you receive from internal radiation sources (i.e. the radioactive atoms inside your body)?

0.4mSv

For an occupation to be considered as having an acceptable level of risk (or high level of safety), what is the annual mortality risk? (number per million).

A safe occupation has an annual mortality risk of about 100 per million.

The D37 Dose is the dose for which survival (S) is 37% and is used to indicate the ______ of the cell line.

radiosensitivity

Double strand breaks require a break in both strands of the DNA, about ____nm apart.

2nm

What are four effects that relate to the gastrointestinal syndrome?

infection fluid loss electrolyte imbalance problems with absorption of metabolites

Based on studies of atomic bomb survivors, marshall island nuclear testing survivors and radiotherapy patient, what are two known risk estimates for induction of thyroid cancer?

8 deaths per million people exposed to 10mSv | 50-150 cases induced per million people exposed to 10mSv

What are three statements that contribute to the debate about whether the linear no threshold model is correct?

to estimate risks for low doses, in information has to be extrapolated from higher doses, and the extrapolation has many uncertainties the doses received in medical imaging and by workers is much less than the ranges actually measured so these workers can't be used in the estimates the LNT modle is based on doses in the range of about 0.2Sv to 5Sv

What is the risk estimate for deaths due to bone cancer (the number per million people exposed to 10mSv)

What is the risk estimate for fatal leukaemia from exposure to the bone marrow (the number per million people exposed to 10mSv)