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60 terms

Rad. Biology Ch.

STUDY
PLAY
lymphocytes
high rad. sens.
erythryblasts
high rad. sens.
spermatogonia
high rad. sens.
intestinal crypt
high rad. sens.
muscle cells
rad. resistant
nerve cells
rad. resistant
chondrocytes
rad. resistant
Relative Biological Effectiveness (RBE)
comparison of dose to test dose of 250 keV that produces the same biological response
LET Linear Energy Transfer
measure of rate at which energy is deposited as charged particles travel through matter
water
most commonly acted upon by ionizing radiation producing indirect effects
non threshold
assumes any radiation dose produces an effect
target theory
DNA is a critical target of exposure
radiolysis
separation of water into hydrogen and oxygen
rem
occupational exposure measure
As LET increases what happens to RBE
it also increases
3 events of cell radiation
slows mitosis, interphase death, and cell death
radiosensitivity depends on what?
what cell cycle+= mitosis
when can chromosome damage be analyzed
During metaphase
radiation interaction happen likeliness
Chance and probability = random
RBE factors
radiation type, cell tissue type, physiologic condition, biologic result examined, and dose rate
Radiation of macromolecules effects
main chain scission, cross linking, and point lesion
cell survival curve
identifies doses that result in inability to reproduce
Linear dose response
observed response is directly proportional to dose
threshold dose response curve
indicates a radiation level below which no effect is observed
non threshold dose response curve
indicates any rad. dose produces an effect
Diagnostic Radiology dose response curve type
linear, non threshold
Leukemia, breast ca. and other genetic damage DRC?
linear,non threshold
Law of B & T states
stem cells more radiosens.
unit of dose equivalent occupational exposure
rem/sievert
free radicals cause
direct effects
indirect ionization causes
direct effect
amount of energy absorbed in matter
rad
measure of ionization in air by x or gamma rays
roentgen
SI unit for roentgen
columbs/kilo
SI unit for rad
gray
SI unit for rem
Sievert
Erythma
skin reddening
3 incidents that triggered radiobiology
atomic bomb 1945, x-rays 1895, radium in 1896
radioactive
capable of giving off rays or particles from it's nucleus
mutagenesis
genetic mutation by radiation
reproductive failure
cell cannot divide after irradiation
Protoplasms contain
organic and inorganic compounds
protoplasm is how much water
85 %
Diploid 2n
23
cell divides twice and chromosomes duplicate once
meiosis
metabolism
catabolism + anabolism
reduction/division
meiosis
duplication/division
mitosis
cell organelles location
in cytoplasm
germ cells contain (haploid)
1/2 or 23 single chromosomes
female somatic cells
44 autosomes and two x
male somatic cells
44 autosomes and one x and one y
Linear quadratic dose response curves are
nonthreshold
underestimates the low dose effect of rad.
linear quadratic dose response curves
Used for effects of low doses of low LET
linear quadratic dose response curve
Radiation guidlines are est.using what curve
linear nonthreshold
high dose effects observed in radiotherapy curve
signoid dose response curve
effect is not directly proportional to the dose curve
sigmoid dose response curve
Target theory
this concept is that there is a sensitive key molecule in the cell (namely DNA), and for the cell to die DNA must be inactivated
Point mutation
rate at which a desired effect is produced