Final exam select topics-radiotoxicity Flashcards

1
Q

what is ionizing radiation

A

radiation with sufficient energy to displace electrons from molecules

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2
Q

what are 2 types of ionizing radiation

A

particles and electromagnetic waves (photons)

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3
Q

what are 4 examples of particle radiation

A

alpha beta protons neutrons

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4
Q

what are 2 examples of electromagnetic waves

A

x and gamma

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5
Q

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

A

alpha

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6
Q

which of alpha beta gamma x are charged

A

alpha beta

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7
Q

which of alpha beta gamma x are uncharged

A

x gamma

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8
Q

which of alpha beta gamma x are zero mass

A

x gamma

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9
Q

how do photons (x gamma) cause ionization

A

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

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10
Q

how do charged particles ( b a ) cause ionization

A

directly collide with electrons of atoms

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11
Q

what is the berequel

A

basic unit of radiation activity, 1nuclear disintegration/second

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12
Q

what is gray

A

basic unit of dose, J released/ kg tissue

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13
Q

what is LET

A

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

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14
Q

which of alpha beta gamma x are low LET

A

gamma x b

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15
Q

which of alpha beta gamma x are high LET

A

alpha and neutrons

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16
Q

what is created when ionizing radiation passes through matter

A

ion pais (electron and +ve atom residue)

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17
Q

what can ionizing radiation do to DNA

A

ds and ss breaks

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18
Q

what are the 3 kinds of doses ( in order )

A

absorbed, equivalent, effective

19
Q

what is absorbed dose (units + definition)

A

gray (J/kg), energy absorbed by target

20
Q

what is equivalent dose (units + definition)

A

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

21
Q

what is effective dose (units + definition)

A

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

22
Q

how do you go from absorbed dose to equivalent dose

A

Wr (radiation weighing factor)

23
Q

how do you go from equivalent dose to effective dose

A

Wt (tissue weighing factor)

24
Q

what is the formula for equivalent dose

A

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

25
Q

what is the formula for effective dose

A

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

26
Q

what does low LET mean for amount of ionization

A

only few will be made

27
Q

what does high LET mean for amount of ionization

A

thousands

28
Q

what does low LET mean for location of ionization

A

in isolated places/ spread out

29
Q

what does high LET mean for location of ionization

A

all in once cluster

30
Q

what are the 3 components of the DNA damage response

A

sensors, transducers and effectors

31
Q

what do the sensors do

A

alert and amplify damage signal to transducers

32
Q

what do transducers do

A

signal damage further to downstream effector proteins

33
Q

what do effectors do

A

lead to cell cycle arrest, apoptosis or repair

34
Q

how can we measure DNA damage using assays

A

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

35
Q

what is gammaH2AX

A

sensor protein for dsDNA breaks

36
Q

what can happen to chromosomes with radiation

A

translocation (fusions)

37
Q

how can chromosomal translocations happen with radiation

A

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

38
Q

what is hormesis

A

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

39
Q

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

A

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

40
Q

what were the main isotops from chernobyl

A

131 I, 137 and 134 cesium

41
Q

what was the main type of issue chernobyl survivors faced

A

thyroid cancer

42
Q

what are 4 stages of radiation sickness

A
  • 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
43
Q

what may be the antidote to radiation maybe

A

DTPA - zinc or calcium conjugates

44
Q

how does DTPA work

A

exchanges its calcium or zine for radionucleotides