Final exam select topics-radiotoxicity

Question 1

what is ionizing radiation

Answer 1

radiation with sufficient energy to displace electrons from molecules

Question 2

what are 2 types of ionizing radiation

Answer 2

particles and electromagnetic waves (photons)

Question 3

what are 4 examples of particle radiation

Answer 3

alpha beta protons neutrons

Question 4

what are 2 examples of electromagnetic waves

Answer 4

x and gamma

Question 5

order alpha gamma neutron x rays and b particles for least to most penetration

Answer 5

alpha

Question 6

which of alpha beta gamma x are charged

Answer 6

alpha beta

Question 7

which of alpha beta gamma x are uncharged

Answer 7

x gamma

Question 8

which of alpha beta gamma x are zero mass

Answer 8

x gamma

Question 9

how do photons (x gamma) cause ionization

Answer 9

transfer energy to electrons which become energetic and are released (indirectly)

Question 10

how do charged particles ( b a ) cause ionization

Answer 10

directly collide with electrons of atoms

Question 11

what is the berequel

Answer 11

basic unit of radiation activity, 1nuclear disintegration/second

Question 12

what is gray

Answer 12

basic unit of dose, J released/ kg tissue

Question 13

what is LET

Answer 13

average energy lost from a charged particle per unit length of trajectory

Question 14

which of alpha beta gamma x are low LET

Answer 14

gamma x b

Question 15

which of alpha beta gamma x are high LET

Answer 15

alpha and neutrons

Question 16

what is created when ionizing radiation passes through matter

Answer 16

ion pais (electron and +ve atom residue)

Question 17

what can ionizing radiation do to DNA

Answer 17

ds and ss breaks

Question 18

what are the 3 kinds of doses ( in order )

Answer 18

absorbed, equivalent, effective

Question 19

what is absorbed dose (units + definition)

Answer 19

gray (J/kg), energy absorbed by target

Question 20

what is equivalent dose (units + definition)

Answer 20

sievert (J/kg), biological effect that depends on radiation type

Question 21

what is effective dose (units + definition)

Answer 21

sievert (J/kg), biological effect on tissue type

Question 22

how do you go from absorbed dose to equivalent dose

Answer 22

Wr (radiation weighing factor)

Question 23

how do you go from equivalent dose to effective dose

Answer 23

Wt (tissue weighing factor)

Question 24

what is the formula for equivalent dose

Answer 24

summation of : Wr (radiation weighing factor) x absorbed dose for each radiation type (DT)

Question 25

what is the formula for effective dose

Answer 25

summation of : Wt (tissue weighing factor) x equivalent dose for each radiation type (HT)

Question 26

what does low LET mean for amount of ionization

Answer 26

only few will be made

Question 27

what does high LET mean for amount of ionization

Answer 27

thousands

Question 28

what does low LET mean for location of ionization

Answer 28

in isolated places/ spread out

Question 29

what does high LET mean for location of ionization

Answer 29

all in once cluster

Question 30

what are the 3 components of the DNA damage response

Answer 30

sensors, transducers and effectors

Question 31

what do the sensors do

Answer 31

alert and amplify damage signal to transducers

Question 32

what do transducers do

Answer 32

signal damage further to downstream effector proteins

Question 33

what do effectors do

Answer 33

lead to cell cycle arrest, apoptosis or repair

Question 34

how can we measure DNA damage using assays

Answer 34

use antibodies to gammaH2AX which is a sensor protein for dsDNA breaks

Question 35

what is gammaH2AX

Answer 35

sensor protein for dsDNA breaks

Question 36

what can happen to chromosomes with radiation

Answer 36

translocation (fusions)

Question 37

how can chromosomal translocations happen with radiation

Answer 37

decrease in telomere repair mechanism or loss of telomeres from ds break (uncappted chromosomes more likely to go through rearrangements)

Question 38

what is hormesis

Answer 38

low doses of radiation can push subsequent DNA damage to below background levels

Question 39

what is the main model of risk (graph) that is accepted (like radiation dose vs risk)

Answer 39

LNT - linear non threshold, straight line (constantly exposed to radiation so its hard to know if theres a threshold)

Question 40

what were the main isotops from chernobyl

Answer 40

131 I, 137 and 134 cesium

Question 41

what was the main type of issue chernobyl survivors faced

Answer 41

thyroid cancer

Question 42

what are 4 stages of radiation sickness

Answer 42

- prodormal (nausea vomit) - latent (better) - illness ( weeks later, CNS disorders, CV and pump issues, bone marrow destruction, cutaneous syndrome-blisters hair loss ulcers) - recovery or death

Question 43

what may be the antidote to radiation maybe

Answer 43

DTPA - zinc or calcium conjugates

Question 44

how does DTPA work

Answer 44

exchanges its calcium or zine for radionucleotides