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4 Cards in this Set
- Front
- Back
What is a Thoraeus filter and where is the highest Z material?
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The Thoraeus filter is a combination filter containing plates of tin, copper, and aluminum and have been designed to increase the resulting half-value layer of the orthovoltage beams without reducing the beam intensity to unacceptably low values.
Combination filters must be arranged with the highest atomic number material nearest the x-ray target. The filter is inserted with tin facing the x-ray tube and the aluminum facing the patient, with copper sandwiched between the tin and the aluminum plates. |
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How do you measure beam quality? Direct and Indirect measurements?
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The quality of x-ray beams is specified by kVp, filtration and HVL (for diagnostic) and MV and percent depth dose in water (for mega-voltage x-rays)
Direct measurement- Voltage Divider, sphere-gap method Indirect measurement- Fluorescence, attenuation, or a penetramter such as an Adrian Crooks cassette. |
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Define "Effective Energy"
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Effective of equivalent energy of an x-ray beam is the energy of a mono-energetic photon beam that has the same HVL as the given beam.
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How do you measure the energy spectrum
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The Energy spectrum of an x-ray beam can be measured by scintillation spectrometry. The spectrum may be displayed in terms of photon fluence per unit energy interval as a function of photon energy.
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