If a cell is irradiated during G1, S or G2 phase it will result in __________.
def: the death of cells before these cells reach mitosis.
aka. non-mitosis or non-division death
A decrease in the reproductive integrity or cells' ability to undergo a limited number of divisions after irradiation
*the most common cellular response*
Irradiated cells that involve a disruption in the mitotic index.
Results of Division Delay:
Cells that are in interphase when irradiation occurs will be delayed in the ______ phase.
The consequence is a decrease in the Mitotic Index for the population, which means that fewer cells than normal will divide.
A _________ of genetic material results when the fragments between the breaks is lost & the remaining 2 fragments join.
Effects on the cell depend on the amount & significance of material lost
An _________ of genetic material reults when the middle fragment with two broken ends turns around or inverts before re-joining the other two fragments.
no genetic material is lost but gene sequence is disrupted, so cell longevity is hurt
_________ are known as radio-protectors but are known to cause side effects.
_________ is the best radiosensitizer.
What is the proper order of the cellular division cycle:
What is the organ system damaged and average time of death in Hematopoietic Syndrome?
3 weeks - 2 months
Hematopoietic syndrome = 100-1000cGy
What is the the organ system damaged and average time of death in Gastrointestinal syndrome?
3 - 10 days
Gastrointestinal syndrome = 1000-5000cGy
What is the organ system damaged and average time of death in Cerebrovascular Syndrome?
Less than 3 days
Cerebrovascular Syndrome > 5000cGy
What is the dose range for Hematopoietic Syndrome?
100 - 1,000 cGy
What is the dose range for Gastrointestinal Syndrome?
1,000 - 5,000 cGy
Cerebrovascular Syndrome occurs after doses of __________.
but can be induced by doses as low as 5,000 cGy and up
What is the formula to fine equivalent dose (Sv) from absorbed dose and quality factor?
Sv = Gy x QF
What is the latent period for leukemia due to radiation?
The time interval between irradiation and the appearance of malignancy is known as the __________ period.
The human fetus is most sensitive to radiation in the __________ trimester.
The immediate symptoms that appear after an acute radiation exposure are termed the __________ phase/syndrome.
What is the proper order of response to acute whole body exposure?
I. Recovery (if dose low enough)
II. Prodromal phase
III. Manifest Period
IV. Latent period
On the cell survival curve, the _________ equals the slope of the curve's linear position. and is a measure of radiosensitivity, with radiosensitive cells having a low value.
On the cell survival curve, The target or extrapolation number, represented by ______, is determined by extrapolating the linear portion of the curve back until it intersects with the y-axis.
Extrapolation number (n)
On the cell survival curve, the dose at which survival becomes exponential, known as the __________, is determined by a measure of the width of the shoulder region of the survival curve.
It is a measure of the cell's ability to accumulate & repair sublethal damage.
Quasi-threshold Dose (Dq)
The __________ is a plot of the radiation dose administered on the x-axis versus the surviving fraction (SF) of cells on the y-axis.
(made by Puck & Marcus)
Cell Survival Curve
The ________ the radiation dose, the _________ the mitotic delay, which results in a decrease in the mitotic index.
the HIGHER the radiation dose, the LONGER the mitotic delay.
When doses are lower than ________ most cell lines will recover and eventually proceed through mitosis.
A ________ contains an unpaired electron in the outer shell, thus making it highly reactive.
Cells attempt to repair radiation damage before ________ by stopping in the ____ phase to confirm that DNA and proteins are intact.
The ratio of the number of mitotic cells to the total number of cells in the irradiated population:
Mitotic Index (MI)
What are the four R's of rad bio?
Thyroid cancer can be caused by total body doses as low as ______.
What is the LD100 for humans?
What is the LD50/60 for humans?
True or False: In Hematopoietic syndrome, the probability of survival is dose dependent.
(probability of survival decreases with an increasing dose)
Bremsstrahlung is more likely to occur with ________ particles.
_________ refers to the replacement of damaged cells by a different cell type, resulting in scar formation or fibrosis. (more likely w/ high dose)
_________ refers to the replacement of damaged cells by the same cell type. (likely to occur in organs w/ VIM & DIM cells)
What are the Traditional and SI units of measure for activity?
Traditional: curie (Ci)
SI: becquerel (Bq)
1 Ci = 3.7 x 1010 Bq
What are the Traditional and SI units of measure for Dose Equivalent?
roentgen equivalent man (rem)
100 rem = 1 Sv
What are the Traditional and SI units of measure for Absorbed Dose?
radiation absorbed dose (rad)
100 rad = 1 Gy = 100 cGy
What are the Traditional and SI units of measure for Exposure?
coulombs per kilogram (C/kg)
1 R = 2.58 x 10-4 C/kg
Examples of _________ effects include cataracts, erythema, skin/tissue burns and sterility.
________ effects occur randomly with probability for effect increasing with dose.
________ effects often show up years after exposure.
Examples of ________ effects consist primarily of cancer & genetic effects.
________ effects have no threshold for occurrence, probability of effect will increase with dose but is not guaranteed.
The severity of a ________ effect is independent of dose.
_________ effects are also known as acute effects.
Non Stochastic effects are also known as __________ effects
A threshold exists for _________ effects.
The severity of _________ effects will increase will the dose but will only occur once the threshold has been reached.
_________ effects generally result from a high dose over a short period of time.
Which effects are of more concern at low levels of exposure?
Quality factor of X-rays & gamma rays:
X-rays & Gamma rays
QF = 1
Quality factor of Beta particles & Positrons:
Beta particles & Positrons
QF = 1
Quality factor of High Energy External Protons:
High Energy External Protons
QF = 1
Quality factor of Protons (other than recoil protons):