Radionuclide Generators Flashcards
(98 cards)
1
Q
When you have neutron excess, you have to go undergo what decay
A
beta decay
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)
3
Q
Symbol: λ
A
decay factor
4
Q
t 1/2
A
physical half life
5
Q
Symbol: A
A
total activity
6
Q
Symbol: A1
A
activity of the parent radionuclide
7
Q
Symbol: A2
A
activity of the daughter radionuclide
8
Q
The radioactivity of the daughter nuclides depends on two factors:
A
rate of its formation + rate of its decay
9
Q
Symbol: A0/1
A
activity of the parent radionuclide at t=0
10
Q
Symbol: A0/2
A
activity of the daughter radionuclide at t=0
11
Q
λ2 / λ2 - λ1
A
constant with a value of 1.003 ~ 1
12
Q
parent and daughter meet and simultaneously decay together
A
Equilibrium point
13
Q
At equilibrium, the ratio of activities of daughter to that of parent (A2/A1) is approximately
A
constant
14
Q
Generally, equilibrium is established approximately by
A
10T2
15
Q
Occurs if the half-life of the parent is significantly greater than the half-life of the daughter
A
secular equilibrium
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
17
Q
What kind of equilibrium is the Decay of Strontium-90 vs Cumulative buildup of Yttrium-90
A
secular equilibrium
18
Q
What kind of equilibrium is the Decay of Molybdenum-99 vs Cumulative buildup of Technetium-99m
A
transient equilibrium
19
Q
what is the time when the activity of Tc99m is at maximum?
A
23 hours
20
Q
Is it possible for daughter activity > parent activity?
A
No
21
Q
What is the BR of Mo99m to Tc99m?
A
87.5% (experimentally determined)
22
Q
term used to describe the probability that parent radionuclide would decay to form daughter radionuclide
A
Branching ratio
23
Q
CH4 (g)
A
Pure Substance
24
Q
Air
A
Mixture
25
Milk
Suspension
26
Tc-Sn
Colloid
27
NSS
Solution
28
NaCl in NSS
Solute
29
H2O in NSS
Solvent
30
Mo99/Tc99m
Solution
31
Field of chemistry that studies the separation between components of a mixture
Separation Chemistry
32
separation based on physical affinity towards something
Chromatography
33
2 Relevant chromatography methods in
radiochemistry
Partitioning
Adsorption
34
Based on relative solubility of the solutes between two fluids of different polarity
Partitioning
35
Based on relative adherence of solutes against active sites of a solid surface
Adsorption
36
Setups to separate repeatedly short-lived daughter nuclides from longer-lived mother nuclides by chemical methods
radionuclide generators
37
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
radionuclide generators
38
This allows show lived radionuclides to be kept in ready supply at hospitals and research facilities, providing a consistent product for routine use
radionuclide generators
39
You cannot transport Tc-99m alone, you have to use another carrier which is the
longer half life parent Mo-99
40
General components of radionuclide generator
system
eluent
volume controller
separation column with parent/daughter radionuclide mixture
vial shield
eluate
0.2 um filter
generator shield
housing
41
process of passing of a liquid to a column to remove desired substance/s
Elution / Milking
42
the one that is pushing the liquid to the column to remove the daughter
eluent
43
controls the volume that enters the separation column
Volume controller
44
the daughter will be removed and the parent will remain
Separation column with parent/daughter radionuclide mixture
45
Separation column with parent/daughter radionuclide mixture
Sorbent / stationary phase
46
you need a lead or tungsten shield that will protect the workers
Generator shield
47
allows the generator to be transported easily
Housing
48
all radionuclide generators must provide sterile and non-pyrogenic solutions
0.2 um filter
49
the vial containing the solution (eluent) and daughter radionuclide
Eluate
50
to protect yourself during radio labeling
Vial shield
51
The entire generator is called a
COW
52
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
Sorbent
53
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
Eluent
54
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
Eluate
55
Radiation resistant materials
High loading capacity
Adequate shielding
Simple and fast production
Simple operation
Generator system
56
Total activity of eluate = ?
sum of all activities prior to elution
57
Total no. of elutions at Amax * Tmax
Generator life
58
Percentage of the eluted radioactivity to the theoretically calculated radioactivity at the time of elution
Elution efficiency
59
Ideal elution efficiency is ___ although ___ is still considered acceptable.
≥ 90% , above 80%
60
Some of the factors that affect elution efficiency:
Generator type
Column defects
Specific activity of the parent radionuclide
Radiolysis of water
61
2 Generator types
Wet and dry generators
62
Has a large reservoir of saline permanently attached to the inlet
Wet generator
63
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
Wet generator
64
The column remains full of saline between elutions
Wet generator
65
Elution is performed with a set volume of saline provided each time by attaching a vial to an inlet to the generator
Dry generator
66
The saline is pulled through the column by a vacuum provided by an empty evacuated vial attached to the outlet of the chromatography column
Dry generator
67
The liquid pulled through the column is followed by an additional volume of air to effectively remove most of the liquid from the column
Dry generator
68
There are several generators that have been developed for research, but only a few were able to reach commercialization and the clinic.
true
69
Most common sorbent: acidic aluminum oxide (Al2O3)
Mo99/Tc99m generators
70
Parent source: Fission-produced Moly using low enriched uranium
Mo99/Tc99m generators
71
Chemical form of the parent: MoO42-
Mo99/Tc99m generators
72
Chemical form of the daughter: TcO4-
Mo99/Tc99m generators
73
Elution volume: 1-10 mL
Mo99/Tc99m generators
74
Method of elution: vacuum
Mo99/Tc99m generators
75
Eluent: NSS
Mo99/Tc99m generator
Sr82/Rb82 generator
W188/Re188 generator
76
# Handle the generator in an environment that ensures sterility
Elution technique 1
77
# If there is a need to disinfect the vial stoppers and allow the disinfectant solution to evaporate before puncturing with a needle
2
78
# If the Tc generator purchased has an adjustable volume such as Polgentec, set the eluate volume before inserting the saline vial.
3
79
# Do not turn the eluate volume knob when the saline vial is already inserted into the socket
4
80
# Do not remove the evacuated vial until elution is completed
5
81
Tc99 competes with Tc99m in chemical binding therefore can
reduce the labeling efficiency in radiopharmaceutical kits
82
This situation becomes critical when the generators are left without elution over the weekend and then first eluted on
Monday or Tuesday
83
Why does Tc99 accumulate in the eluate?
T1/2 of Tc99 = 2.11 x 10^5 years
84
trade name of Sr82/Rb82 generator
Cardiogen-82
85
Sorbent: SnO2
Sr82/Rb82 generator
86
Elution technique: syringe pump
Sr82/Rb82 generator
87
Unique feature: can be directly connected to the patient using an infusion system for myocardial perfusion
Sr82/Rb82 generator
88
First PET generator approved by the FDA
Sr82/Rb82 generator
89
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.
50 mL of NSS
90
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
an hour
91
trade name of W188/Re188 generator
Oncobeta
92
Parent source: Reactor-produced Tungsten-188 (carrier-free)
W188/Re188 generator
93
Chemical form of eluate: Na188ReO4
W188/Re188 generator
94
Sorbent: Al2O3
W188/Re188 generator
95
Elution volume: 5-14 mL
W188/Re188 generator
96
Elution efficiency: 75-85%
W188/Re188 generator
97
Elution technique: vacuum or syringe pump option
W188/Re188 generator
98
How many weeks is the maximum time for the 188W/188Re generator to be left uneluted?
3 weeks
