Radionuclide Generators Flashcards

1
Q

When you have neutron excess, you have to go undergo what decay

A

beta decay

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2
Q

means that Sr-90 will decay into multiple particles. It will not only undergo beta-decay, but also positron, isomeric transition etc.

A

The Branching Ratio (BR)

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3
Q

Symbol: λ

A

decay factor

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4
Q

t 1/2

A

physical half life

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5
Q

Symbol: A

A

total activity

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6
Q

Symbol: A1

A

activity of the parent radionuclide

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7
Q

Symbol: A2

A

activity of the daughter radionuclide

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8
Q

The radioactivity of the daughter nuclides depends on two factors:

A

rate of its formation + rate of its decay

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9
Q

Symbol: A0/1

A

activity of the parent radionuclide at t=0

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10
Q

Symbol: A0/2

A

activity of the daughter radionuclide at t=0

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11
Q

λ2 / λ2 - λ1

A

constant with a value of 1.003 ~ 1

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12
Q

parent and daughter meet and simultaneously decay together

A

Equilibrium point

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13
Q

At equilibrium, the ratio of activities of daughter to that of parent (A2/A1) is approximately

A

constant

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14
Q

Generally, equilibrium is established approximately by

A

10T2

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15
Q

Occurs if the half-life of the parent is significantly greater than the half-life of the daughter

A

secular equilibrium

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16
Q

Occurs if the half-life of the parent is only a few times greater than the half-life of the daughter

A

transient equilibrium

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17
Q

What kind of equilibrium is the Decay of Strontium-90 vs Cumulative buildup of Yttrium-90

A

secular equilibrium

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18
Q

What kind of equilibrium is the Decay of Molybdenum-99 vs Cumulative buildup of Technetium-99m

A

transient equilibrium

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19
Q

what is the time when the activity of Tc99m is at maximum?

A

23 hours

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20
Q

Is it possible for daughter activity > parent activity?

A

No

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21
Q

What is the BR of Mo99m to Tc99m?

A

87.5% (experimentally determined)

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22
Q

term used to describe the probability that parent radionuclide would decay to form daughter radionuclide

A

Branching ratio

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23
Q

CH4 (g)

A

Pure Substance

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24
Q

Air

A

Mixture

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25
Q

Milk

A

Suspension

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26
Q

Tc-Sn

A

Colloid

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27
Q

NSS

A

Solution

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28
Q

NaCl in NSS

A

Solute

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29
Q

H2O in NSS

A

Solvent

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30
Q

Mo99/Tc99m

A

Solution

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31
Q

Field of chemistry that studies the separation between components of a mixture

A

Separation Chemistry

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32
Q

separation based on physical affinity towards something

A

Chromatography

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33
Q

2 Relevant chromatography methods in
radiochemistry

A

Partitioning
Adsorption

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34
Q

Based on relative solubility of the solutes between two fluids of different polarity

A

Partitioning

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35
Q

Based on relative adherence of solutes against active sites of a solid surface

A

Adsorption

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36
Q

Setups to separate repeatedly short-lived daughter nuclides from longer-lived mother nuclides by chemical methods

A

radionuclide generators

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37
Q

A resin (usually ion-exchange) -bound, longer- lived parent radionuclide decays to chemically different daughter nuclide which can be subsequently separated easily from the parent

A

radionuclide generators

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38
Q

This allows show lived radionuclides to be kept in ready supply at hospitals and research facilities, providing a consistent product for routine use

A

radionuclide generators

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39
Q

You cannot transport Tc-99m alone, you have to use another carrier which is the

A

longer half life parent Mo-99

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40
Q

General components of radionuclide generator
system

A

eluent
volume controller
separation column with parent/daughter radionuclide mixture
vial shield
eluate
0.2 um filter
generator shield
housing

41
Q

process of passing of a liquid to a column to remove desired substance/s

A

Elution / Milking

42
Q

the one that is pushing the liquid to the column to remove the daughter

A

eluent

43
Q

controls the volume that enters the separation column

A

Volume controller

44
Q

the daughter will be removed and the parent will remain

A

Separation column with parent/daughter radionuclide mixture

45
Q

Separation column with parent/daughter radionuclide mixture

A

Sorbent / stationary phase

46
Q

you need a lead or tungsten shield that will protect the workers

A

Generator shield

47
Q

allows the generator to be transported easily

A

Housing

48
Q

all radionuclide generators must provide sterile and non-pyrogenic solutions

A

0.2 um filter

49
Q

the vial containing the solution (eluent) and daughter radionuclide

A

Eluate

50
Q

to protect yourself during radio labeling

A

Vial shield

51
Q

The entire generator is called a

A

COW

52
Q

Material stable against radiation
Nontoxic
Insoluble
Good mechanical properties
Good packing and flow characteristics
Easy to prepare and handle
Very strong binding of parent isotope, preferably total immobilization

A

Sorbent

53
Q

Non-reactive towards adsorbed parent isotope
Rapidly reacting with daughter isotope
Convert daughter isotope to chemical form nonreactive to sorbent Non-toxic
Physiological pH
Isotonic
Chemically stable

A

Eluent

54
Q

Can be obtained in volume as low as 1 mL
High elution yield
Minimum breakthrough of parent isotope even in multiple elutions Sterile
Pyrogen-free

A

Eluate

55
Q

Radiation resistant materials
High loading capacity
Adequate shielding
Simple and fast production
Simple operation

A

Generator system

56
Q

Total activity of eluate = ?

A

sum of all activities prior to elution

57
Q

Total no. of elutions at Amax * Tmax

A

Generator life

58
Q

Percentage of the eluted radioactivity to the theoretically calculated radioactivity at the time of elution

A

Elution efficiency

59
Q

Ideal elution efficiency is ___ although ___ is still considered acceptable.

A

≥ 90% , above 80%

60
Q

Some of the factors that affect elution efficiency:

A

Generator type
Column defects
Specific activity of the parent radionuclide
Radiolysis of water

61
Q

2 Generator types

A

Wet and dry generators

62
Q

Has a large reservoir of saline permanently attached to the inlet

A

Wet generator

63
Q

Each elution pulls liquid from the column by a vacuum in an evacuated vial attached to the outlet of the chromatography column but this liquid is replaced by a volume of saline from the reservoir

A

Wet generator

64
Q

The column remains full of saline between elutions

A

Wet generator

65
Q

Elution is performed with a set volume of saline provided each time by attaching a vial to an inlet to the generator

A

Dry generator

66
Q

The saline is pulled through the column by a vacuum provided by an empty evacuated vial attached to the outlet of the chromatography column

A

Dry generator

67
Q

The liquid pulled through the column is followed by an additional volume of air to effectively remove most of the liquid from the column

A

Dry generator

68
Q

There are several generators that have been developed for research, but only a few were able to reach commercialization and the clinic.

A

true

69
Q

Most common sorbent: acidic aluminum oxide (Al2O3)

A

Mo99/Tc99m generators

70
Q

Parent source: Fission-produced Moly using low enriched uranium

A

Mo99/Tc99m generators

71
Q

Chemical form of the parent: MoO42-

A

Mo99/Tc99m generators

72
Q

Chemical form of the daughter: TcO4-

A

Mo99/Tc99m generators

73
Q

Elution volume: 1-10 mL

A

Mo99/Tc99m generators

74
Q

Method of elution: vacuum

A

Mo99/Tc99m generators

75
Q

Eluent: NSS

A

Mo99/Tc99m generator
Sr82/Rb82 generator
W188/Re188 generator

76
Q

Handle the generator in an environment that ensures sterility

A

Elution technique 1

77
Q

If there is a need to disinfect the vial stoppers and allow the disinfectant solution to evaporate before puncturing with a needle

A

2

78
Q

If the Tc generator purchased has an adjustable volume such as Polgentec, set the eluate volume before inserting the saline vial.

A

3

79
Q

Do not turn the eluate volume knob when the saline vial is already inserted into the socket

A

4

80
Q

Do not remove the evacuated vial until elution is completed

A

5

81
Q

Tc99 competes with Tc99m in chemical binding therefore can

A

reduce the labeling efficiency in radiopharmaceutical kits

82
Q

This situation becomes critical when the generators are left without elution over the weekend and then first eluted on

A

Monday or Tuesday

83
Q

Why does Tc99 accumulate in the eluate?

A

T1/2 of Tc99 = 2.11 x 10^5 years

84
Q

trade name of Sr82/Rb82 generator

A

Cardiogen-82

85
Q

Sorbent: SnO2

A

Sr82/Rb82 generator

86
Q

Elution technique: syringe pump

A

Sr82/Rb82 generator

87
Q

Unique feature: can be directly connected to the patient using an infusion system for myocardial perfusion

A

Sr82/Rb82 generator

88
Q

First PET generator approved by the FDA

A

Sr82/Rb82 generator

89
Q

In Sr82/Rb82 generators, Before any patient is administered, the generator is eluted with _____ and immediately the Rb82 activity is measured and decay corrected to end of elution.

A

50 mL of NSS

90
Q

Then, the activity is allowed to decay for (how long?) and the breakthrough activity A in μCi is measured which contains Sr-82 and Sr-85

A

an hour

91
Q

trade name of W188/Re188 generator

A

Oncobeta

92
Q

Parent source: Reactor-produced Tungsten-188 (carrier-free)

A

W188/Re188 generator

93
Q

Chemical form of eluate: Na188ReO4

A

W188/Re188 generator

94
Q

Sorbent: Al2O3

A

W188/Re188 generator

95
Q

Elution volume: 5-14 mL

A

W188/Re188 generator

96
Q

Elution efficiency: 75-85%

A

W188/Re188 generator

97
Q

Elution technique: vacuum or syringe pump option

A

W188/Re188 generator

98
Q

How many weeks is the maximum time for the 188W/188Re generator to be left uneluted?

A

3 weeks