RADT 1200 Final Exam Questions and Answers All Correct
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Course
RADT 1200
Institution
RADT 1200
RADT 1200 Final Exam Questions and Answers All Correct
What is the end result of photointegration? - Answer-one nuclear fragment
What is the law od Bergonie & Tribondeau? - Answer-states that cells are most radiosensitive when they are:
Stem
Young
High metabolic activity
High proliferati...
RADT 1200 Final Exam Questions
and Answers All Correct
What is the end result of photointegration? - Answer-one nuclear fragment
What is the law od Bergonie & Tribondeau? - Answer-states that cells are most
radiosensitive when they are:
Stem
Young
High metabolic activity
High proliferation rate
What are physical factors affecting radiosensitivity? - Answer-LET- Linear energy
transfer
RBE- Relative biologic effectiveness
What is LET? - Answer-a measure of the rate at which ionizing radiation deposits
energy in tissue
-also known as stopping pair
-keV/µm
-LET of x-rays is 3 keV/µm
What is RBE? - Answer-a quantitative measure of a type of radiation's ability to
produces biologic damage
-RBE of x-rays is 1.
What is the relationship between RBE and LET? - Answer-direct
What is fractionation? - Answer--delivery of dose in fractions
-less effective (cause less damage) than a single large dose
-Tissue repair and recovery occurs between doses
What is protraction? - Answer--A continuous dose delivered at a low rate (over a long
period of time)
-Less effective (causes less damage) than a large dose, delivered quickly
What are biologic factors affecting radiosensitivity? - Answer-Oxygen effect
Age
Sex
Recovery
Chemicals
,Oxygen effect is __________ related to LET - Answer-Indirectly
Oxygen effect is described numerically by the _________ ________ ________. -
Answer-oxygen enhancement ratio (OER)
Tissue is ________ sensitive when oxygenated. - Answer-more
When are humans the most radiosensitive? - Answer-In utero (before birth)
When are humans less sensitive? - Answer-when mature but then get more sensitive
with advance age
Which sex is more radiosensitive? - Answer-Males
T/F: if dose received is sub-lethal, cell may recover from damage. - Answer-True
What are radiosensitizers? - Answer-Any chemical which enhances the effect of
radiation.
What are radioprotectors? - Answer-Any chemical which inhibits the effect of radiation.
Ineffective due to necessity of high doses.
You may be able to get a chemical that's high enough but the chemical itself is going to
kill you.
What is target theory? - Answer-Each cell contains sensitive "key" molecules. In order
for a cell to die following exposure, this "key" or "target" molecule must be inactivated
What is the target molecule in the target theory? - Answer-DNA
What is direct effect in target theory? - Answer-Ionizing radiation strikes a sensitive
molecule (DNA) directly and affects it
-This is highly unlikely because DNA is only 1% of our total composition
What is indirect effect in target theory? - Answer-nIonizing radiation strikes a distant
molecule, and indirectly affects the molecule in question (DNA)
-It's still affecting DNA but indirectly through water.
-95% of damage because water makes up 80% of water
What is radiolysis of water? - Answer-Irradiation of water causes the creation of
molecular products.
What is the result of radiolysis of water? - Answer-formation of an ion pair and free
radicals
, What is a free radical? - Answer-Uncharged molecule containing an unpaired electron in
its outermost shell.
Free radicals may combine to form ________ __________. This can be highly toxic and
poisonous to cells? - Answer-hydrogen peroxide
What are DNA effects? - Answer-Point Mutations
-Single Strand Break
-Double Strand Break
-Cross Linking
-Rung breakage and separation of bases
-Loss of a base
Point mutations may lead to? - Answer-May lead to cell death, malignancies or genetic
damage.
What is the smallest part of an element that possessed all the properties of that
element? - Answer-Atom
Who developed the atomic model in 1913? - Answer-Niels Bohr
What is a molecule? - Answer-combinations of atoms of various elements
What element plays a huge role in the radiation effects on the body? - Answer-Water
What is a compound? - Answer-molecules that contain at least 2 different elements
What is characterized by the SHARING of electrons? - Answer-Covalent Bonding
What type of bonding occurs when atoms of OPPOSITE charges are ATTRACTED to
each other? - Answer-Ionic bonding
Which type of bonding is caused by ionization? - Answer-Ionic bonding
H2O makes up approximately what percent of the body? - Answer-80
Over 95% of the body is comprised of only 4 elements, what are they? - Answer-
Hydrogen, oxygen, carbon, nitrogen
The mass of proton and neutrons is what? - Answer-1
T/F Atomic mass unit is more precise than atomic mass number. - Answer-True
What is the mass for an electron? - Answer-0
What letter corresponds with "atomic number"? - Answer-"Z" Number
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