Notes in 09 General radiography

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Published	05/01/2023	Imaging Physics: General RadiographyX-ray {{c2::photons}} are generated when high-energy {{c1::electrons}} hit a target (tungsten) at t…
Published	05/01/2023	Imaging Physics: General RadiographyAfter colliding with the tungsten target, the electrons’ kinetic energy is converted to {{c1::heat}} (99%) and {{c…
Published	05/01/2023	Imaging Physics: General Radiography90% of X-rays are produced from {{c1::bremsstrahlung (nuclear field interaction)}}, whereas 10% are produced from …
Published	05/01/2023	Imaging Physics: General RadiographyThe maximum keV (Emax) of the filtered X-ray spectrum is the {{c2::kV}} of the generator; however, the a…
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Bremsstrahlung}} radiation is produced when high-energy electrons are deflected by a charged particle via {{…
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Characteristic}} radiation is produced when high-energy electrons knock a(n) {{c2::K-shell electron}} o…
Published	05/01/2023	Imaging Physics: General RadiographyTo eject a K-shell electron, a high-energy electron must have keV {{c1::>::>/</=}} k-shell binding energy
Published	05/01/2023	Imaging Physics: General RadiographyAfter ejection of the K-shell electron, a(n) {{c1::outer shell electron}} fills the vacancy
Published	05/01/2023	Imaging Physics: General RadiographyAs the outer shell electron fills the vacancy of the ejected k-shell electron, a {{c1::single x-ray photon}} is em…
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic Energy = E({{c2::k}}-shell) - E({{c1::transition}}-shell)
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic X-rays {{c2::are not::are/are not}} generated when when kV {{c1::<}} K-edge
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic x-rays are produced with energies just {{c1::below::above/below}} k-shell binding energy
Published	05/01/2023	Imaging Physics: General RadiographyK-absorption edge (K-edge) refers to the abrupt increase in the {{c1::photoelectric absorption}} of phot…
Published	05/01/2023	Imaging Physics: General RadiographyX-ray production is proportional to {{c1::(kV)2}}
Published	05/01/2023	Imaging Physics: General RadiographyChanges in kV causes a change in {{c1::characteristic::type}} X-rays, shifts the spectrum to the {{c2::right::righ…
Published	05/01/2023	Imaging Physics: General Radiography↑ kV by {{c1::15}}% → ↑ photons by {{c2::100}}%
Published	05/01/2023	Imaging Physics: General RadiographyIn general, {{c2::increasing::increasing/decreasing}} kV will {{c1::decrease::increase/decrease}} dose and {{c1::d…
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Heel}} effect is due to {{c2::attenuation}} at the anode, causing {{c3::fewer::greater/fewer}} X-rays a…
Published	05/01/2023	Imaging Physics: General RadiographyThe main contributor to the heel effect is the {{c1::anode angle (~15°)}}
Published	05/01/2023	Imaging Physics: General RadiographyAnode angle is {{c1::inversely::directly/inversely}} proportional to the Heel effect
Published	05/01/2023	Imaging Physics: General Radiography{{c2::Coherent}} scatter occurs when an incoming, low-energy {{c1::photon}} ricochets off an atom
Published	05/01/2023	Imaging Physics: General RadiographyDoes Coherent scatter result in change in frequency?{{c1::No}}
Published	05/01/2023	Imaging Physics: General RadiographyDoes Coherent scatter contribute to patient dose?{{c1::No}}
Published	05/01/2023	Imaging Physics: General RadiographyDoes Coherent scatter result in exchange of energy?{{c1::No}}
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Compton}} scatter occurs when an incoming {{c2::photon}} ricochets off an atom and ejects a(n…
Published	05/01/2023	Imaging Physics: General RadiographyIn Compton scatter, the photon is scattered with a {{c1::longer::longer/shorter}} wavelength, {{c2:…
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Compton}} scatter is proportional to {{c2::electron density}} divided by {{c3::incoming photon ene…
Published	05/01/2023	Imaging Physics: General RadiographyCompton scatter dominates at {{c1::>::>/</=}} 25 keV in soft tissue and {{c1::>::>/</=}} 40 keV …
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Photoelectric}} effect occurs when an incoming {{c2::photon}} is absorbed and ejects a(n) {{c3::inner s…
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Photoelectric}} effect is proportional to {{c2::(electron number)3}} divided by {{c3::(incoming ph…
Published	05/01/2023	Imaging Physics: General RadiographyPhotoelectric effect dominates at {{c1::<::>/</=}} 25 keV in soft tissue and {{c1::<::>/</=}} 40…
Published	05/01/2023	Imaging Physics: General RadiographyIn the equation: N = N0 * e-μt N = {{c1::# photons transmitted}}N0 =  {{c1::initial # pho…
Published	05/01/2023	Imaging Physics: General RadiographyIn the equation: N = N0 * e-μt μ is measured in {{c1::cm-1::units}}
Published	05/01/2023	Imaging Physics: General RadiographyIn the equation: N = N0 * e-μt If μ is {{c1::small (<0.1/cm)::small/large}}, then μ is the …
Published	05/01/2023	Imaging Physics: General RadiographyIn the equation: N = N0 * e-μt If μ is {{c1::large (>0.1/cm)::small/large}}, then the formula ab…
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Mass attenuation}} coefficient is equal to {{c2::linear attenuation coefficient (μ)}} divided by {{c3::…
Published	05/01/2023	Imaging Physics: General RadiographyIn radiography, the typical scatter:primary ratio is {{c1::5–10}}:{{c1::1}}
Published	05/01/2023	Imaging Physics: General RadiographyX-ray Scatter is {{c1::inversely::directly/inversely}} proportional to Contrast
Published	05/01/2023	Imaging Physics: General RadiographyGrid ratio = {{c1::height}} / {{c1::width}}
Published	05/01/2023	Imaging Physics: General RadiographyWhat percent of primary radiation passes through the grid?{{c1::~70%}}
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Bucky}} factor reflects the relative increased radiation dose required when using a grid
Published	05/01/2023	Imaging Physics: General RadiographyBucky factor is the ratio of radiation on the {{c1::grid (incidental)}} to the {{c2::transmitted}} radiation
Published	05/01/2023	Imaging Physics: General RadiographykV is {{c1::directly::directly/inversely}} proportional to scatter
Published	05/01/2023	Imaging Physics: General RadiographyGrids are not used for {{c1::extremity::body/extremity}} radiography, as bone is ↑ Z and not very thick
Published	05/01/2023	Imaging Physics: General RadiographyA “high quality” beam has {{c1::low}}-energy photons filtered out
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Half-value layer (HVL)}} is a measurement of the beam quality and is the {{c2::thickness}} of material …
Published	05/01/2023	Imaging Physics: General RadiographyHalf-value layer (HVL) is {{c1::directly::directly/inversely}} proportional to photon energy
Published	05/01/2023	Imaging Physics: General RadiographyWhat is the standard material for measuring half-value layer (HVL)?{{c1::Aluminum (Al)}}
Published	05/01/2023	Imaging Physics: General RadiographyTypical HVL for mammography is {{c1::0.3}} mm Al
Published	05/01/2023	Imaging Physics: General RadiographyTypical HVL for radiography is {{c1::3}} mm Al
Published	05/01/2023	Imaging Physics: General RadiographyTypical HVL for CT is {{c1::8-9}} mm Al
Published	05/01/2023	Imaging Physics: General Radiography{{c2::Film optical density (OD)}} = log10(I0/It) = log10({{c1::incident}} / {{c1::transmitted light intensity}})
Published	05/01/2023	Imaging Physics: General RadiographyFilm optical density (OD)OD of 1 → {{c1::10}}% photons transmitted through filmOD of 2 → {{c2::1}}% tran…
Published	05/01/2023	Imaging Physics: General RadiographyFilm “looks good” if the average OD is ~{{c1::1.5::#}}, which occurs after approximately {{c2::5 μGy::#}} photons …
Published	05/01/2023	Imaging Physics: General RadiographyA characteristic curve logarithmically plots the relationship between {{c1::radiation exposure (air kerma)}} and {…
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic curve:Low-exposure region is the "{{c1::Toe}}"
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic curve:High-exposure region is the "{{c1::Shoulder}}"
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic curve:Baseline low-level {{c2::darkening}} of film that occurs in the absence of radiation exposure…
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic curve:{{c1::Latitude}} is the range of air kerma with satisfactory film density.
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic curve:In tissues with wide variation of X-ray transmission (e.g., chest radiograph), {{c1::Hig…
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic curve:In tissues with low subject contrast (e.g., mamography), {{c1::high::high/low}}-con…
Published	05/01/2023	Imaging Physics: General RadiographyCharacteristic curve:{{c1::Gamma}} is the steepest part of the curve, and {{c2::gradient}} is the average steepnes…
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Ionization chamber}} is a digital detector that uses high-pressure {{c2::Xe::medium}} (k-edge ~{{c…
Published	05/01/2023	Imaging Physics: General RadiographyAll digital detectors are Solid State detectors except {{c1::Xe (ionization chamber)}}
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Photostimulable phosphor}} is a digital detector that uses {{c2::Barium fluorohalide (BaFBr)::medium}} …
Published	05/01/2023	Imaging Physics: General RadiographyPhotostimulable phosphor is a digital detector that emits {{c1::blue}} light and is read out with {{c1::red}}…
Published	05/01/2023	Imaging Physics: General RadiographyPhotostimulable phosphor is a digital detector that has a dynamic range of {{c1::10,000}}:1
Published	05/01/2023	Imaging Physics: General RadiographyPhotostimulable phosphor is a digital detector that can be used with air kerma <{{c1::0.1}} to {{c1::1000}…
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Scintillator}} is a digital detector that uses {{c2::Cesium iodide (Csl)::medium}}
Published	05/01/2023	Imaging Physics: General RadiographyIn digital detectors, Cesium and Selenium are used {{c1::without::with/without}} a cassette
Published	05/01/2023	Imaging Physics: General RadiographyIn the {{c2::Scintillator}} type digital detector, absorbed X-rays are converted to {{c1::light}}, …
Published	05/01/2023	Imaging Physics: General Radiography{{c2::Scintillator}} is a type of digital detector with a {{c1::high (~30)::high/low}} K-edge, rend…
Published	05/01/2023	Imaging Physics: General RadiographyDoes the Scintillator-type digital detector spread out light resulting in blur?{{c1::Yes}}
Published	05/01/2023	Imaging Physics: General Radiography{{c1::Photoconductor}} is a type of digital detector that uses {{c2::Selenium::medium}} in {{c3::digital mammograp…
Published	05/01/2023	Imaging Physics: General RadiographyIn the {{c1::Photoconductor}} type digital detector, absorbed X-rays are directly converted to {{c2…
Published	05/01/2023	Imaging Physics: General RadiographyDoes the Photoconductor-type digital detector spread out light resulting in blur?{{c1::No}}
Published	05/01/2023	Imaging Physics: General Radiography{{c2::Photoconductor}} is a type of digital detector with a {{c1::low (~13)::high/low}} K-edge…
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