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7 Cards in this Set
- Front
- Back
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True or False:
Radiation does are among diagnostic radiology are the highest in CT. |
True
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What is an easy and accurate way to measure patient dose?
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the CTDI- CT Dose Index.
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What is the CTDI?
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CTDI is a ionization chamber in which a small air filled container with walls thin enough that the xrays can pass thru. As the xrays collide with air mollicules inside the container they lose one or more electrons, "ionize"
The free electrons are electrically charge and that charge is collected and measured on a wire / plate. *Exposure is measured not dose. |
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What is MSAD?
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MSAD- mulitple scan average dose. which is obtained by sampling the highest and lowest dose intervals and averaging them together to create a MSAD
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What is BI? and what is another term for it?
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-Bed Index
-Slice spacing |
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How does BI affect MSAD>?
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As BI increases, MSAD generally decreases.
So if the slices are spaced farther apart and the radiation is spread over a greater distance the average dose becomes smaller. |
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What are some ways to reduce MSAD / overall patient dose?
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- Increase BI or slice spacing
- Reducing the area under the dose profile curve - Narrow slice width - Same beam and detector width, to avoid misalignments / imperfections in - If beam is narrowed more scans are required - Reducing mA, which reduces the height of the dose profile curve |
