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8 Cards in this Set
- Front
- Back
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What do medical tracers use?
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Beta or Gamma radiation
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How does a tracer work?
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A source that emits beta or gamma radiation is injected into the patient or swallowed.
Radiation moves around body and can be detected externally. radiographer can get a snapshot of its distribution. Computer converts to onscreen display shows radiation. can check organs. |
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Does a tracer have a long or short life?
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short!
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Why would alpha radiation be bad for a tracer?
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it would be stopped by tissue so never detected externally. also strong ionising power makes it really harmful for you insides.
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What can Gamma radiation be used for?
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Industrial tracer. same as body to look for cracks. Must have short half life.
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How do scientists date rocks and specimens?
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Measure the amount of radioactive isotope left in the sample. They know its half-life so can see how old it is.
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What are igneous rocks and how can we tell how old they are?
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They contain radioactive uranium which has a long half-life. It decays to become stable isotopes of lead. so can see how old by proportions of lead vs uranium.
Also same goes with potassium-40 to argon in Uranium. |
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What is carbon dating and how work?
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Carbon-14 is one ten millionth in living things at a constant level. when they die the trapped C-14 in wood, bones etc. is beta-emitting RADIOACTIVE ISOTOPE so decays over time.
The ratio of C-12 to C14 is fixed so comparing a living sample with dead can help estimate the age. |
