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23 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What are the 4 main sources of radioactive material?
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1. Accelerators
2. Fission Reactors 3. Naturally Occurring 4. Radionuclide Generators |
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What is "carrier free" material and what is the process that can produce it?
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Transmutation, which can happen in Cyclotron collider or fission reactor
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What happens in a cyclotron accelerator?
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2 D shaped spirals are sandwiched between 2 electromagnets and a charged ion is accelerated through them by alternating the current. The ion is slammed into a target forcing a nuclear reaction. What particles are normally used?
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protons or 2H, 3H or 4H
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What Nuclear Medicine isotopes are produced in a cyclotron?
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Tl201
I123 In111 Ga67 How about PET isotopes? |
N13
O15 F18 |
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Complete this transmutation, direct reaction:
816O +? -> 918F + n |
816O + 3H -> 918F + n
and this one?: 3068Zn + ? => 3167Ga + 2n |
3068Zn + p -> 3167Ga + 2n
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14 N + _____ -> 16O + n
The equation above takes place in a cyclotron. Fill in the blanks with possible particles |
14N + 3H -> 16O +n
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What is the difference between a fast neutron and a thermal neutron?
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Fast neutrons are too fast to react with anything and have ≥ 0.1 MeV
thermal neutrons are below that level and are reactive |
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What are control rods?
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Control reaction rate in a fission reactor. absorb neutrons, composed of boron or cadmium
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Fission must be initiated by ________
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Fission must be initiated by neutrons
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What is the fission mass conservation equation?
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E= (M-m1-m2-mn)c2 (squared)
M=mass of fissioned nucleus m1,m2 = mass of fissioned fragments Mn = mass of neutrons |
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Explain why there is so much energy released when there is fission of U235?
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It breaks into fragments that both have a higher binding energy than the original U 235
What is the ratio and probable mass of the 2 fragments? |
60/40
141/94 |
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What are the 2 reasons fission fragments are important to Nuclear Medicine?
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1. Fission fragments are radioactive and can be separated into medical tracers like I141 or Mo99
2. Neutrons can be used to produce more radioactive material through "neutron activation" |
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Natural uranium contains __% U235, enriched uranium for reactor fuel contains __% uranium and weapons grade uranium contains __% U235
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Natural uranium contains 0.7% U235, enriched uranium for reactor fuel contains 3-5% uranium and weapons grade uranium contains 85+% U235
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What is a neutron activation reaction?
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Capture of a neutron by a stable nucleus transforming it into a radioactive substance
Product is always an isotope of the parent, atomic mass increases by 1 and it produces gamma ray (n,γ) reaction 32P + n --> 33P + γ Parent is never completely activated resulting in the product as always having a carrier, difficult to separate |
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Explain a n,p transmutation reaction
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Process where one element is converted into another
(n,p) reaction 32S + n --> 32P + p Target and product are isobars, same mass but different elements What is beneficial concerning NM with this type reaction? |
Can be separated resulting in a carrier free product
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What are the 3 things that naturally occurring radioactivity series have in common?
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1. long lived 1st member of series
2. each series has a gaseous member 3. each series ends in a stable isotope of lead |
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Besides Thorium, Uranium, Neptunium and Actinium series decays that occur naturally name 2 other important radioactive isotopes in nature important for human exposure:
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1. Potassium 40
2. Carbon 14 (from N14 in atmosphere, incorporated into plants) |
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What is a radionuclide generator?
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Basically a box where radioactive material is placed that decays into something that we want
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Name the 3 type transformations that take place in a radionuclide generator
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1. Secular equilibrium
2. Transient equilibrium 3. No equilibrium situation |
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What is secular equilibrium?
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half life of parent is much greater than the half life of daughter
very slow decaying parent, equilibrium reached after daughter decays 4 half lives what is equilibrium? |
when the activity of the parent and daughter are about constant
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Give an example of a secular equilibrium reaction that is useful for NM?
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Cardio-Gen 82 generator used to produce isotope for PET scanning for cardiac imaging. Sr-82 with 25 day half life decays to Rb-82 with half life of 75 sec. has to be directly hooked up to patient because of short half life. So you have to use stress induced pharmaceutical, not treadmill in this study
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What is Transient Equilibrium?
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Occurs when half life of the parent is longer than the half life of the daughter, but not extremely longer (Tp > Td)
As the parent isotope decays the daughter builds up from 0 and surpasses the parent activity, also in about 4 daughter half lives Equilibrium is reached when there is parallel decay, the ratio of the parent and the daughter remain constant...example for NM? |
Most important application to nuclear medicine as this is how Tc99m is created from Mo99
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What is a no equilibrium reaction?
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occurs when the half life of the parent is shorter than the daughter
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