FLUOROSCOPY ARRT EXAM STUDY GUIDE WITH COMPLETE SOLUTIONS

FLUOROSCOPY ARRT EXAM STUDY GUIDE WITH COMPLETE SOLUTIONS. what mag modes are available? - CORRECT ANSWER-if you have a 16" II, you can have 12,9,6, and 4.5 " Compton effect - CORRECT ANSWER-hits the outer electron, incomplete transfer of energy, electron released and a low energy xray is deflected photoelectric absorption - CORRECT ANSWER-x-ray totally absorbed by inner shell electron, x-ray overcomes binding energy and knock out the electron and an outer shell electron takes it place. When the outer electron moves to its new place, a characteristic x-ray is formed what is the product of photoelectric absorption? - CORRECT ANSWER-electron flying , characteristic x-ray, and positive ion coherent scatter - CORRECT ANSWER-aka Thompson scatter, Rayleigh scatter or classical scatter. x-ray is absorbed by entire atom and is sent off in another direction with no energy loss does coherent scatter result in patient dose? - CORRECT ANSWER-No, this reaction only causes excitation of the atoms shells, but there is not energy transfer nor does the x-ray lose energy ( isotropic) what is the chance of coherent scatter occurring? - CORRECT ANSWER-5% attenuation - CORRECT ANSWER-the drop of intensity of the beam due to absorption and scatter photoelectric interaction is dependent on - CORRECT ANSWER-Z^ 3 and 1/E^3 as photon energy increases there is more - CORRECT ANSWER-penetration and a decrease in tissue interactions Compton is dependent on - CORRECT ANSWER-energy level ( the higher it is, the greater probability of occurrence), electrons/ gram attenuation equation - CORRECT ANSWER-I= Io e^ (-ux) initial energy x e^( attenuation factor x tissue thickness)= resulting energy initial energy- resulting energy= absorbed energy u ( tissue attenuation coeffient) is dependent on - CORRECT ANSWER-keV and material what is the source of free electrons? - CORRECT ANSWER-cathode what is the cathode made of? - CORRECT ANSWER-98% tungsten, 1-2% thorium in what direction are electrons accelerated? - CORRECT ANSWER-cathode to anode how do we focus electron? - CORRECT ANSWER-we use a focusing cup made of nickel that has a greater negative charge. This negative charge repels and squishes the electrons that are made from thermionic emission how does deceleration occur in electrons? - CORRECT ANSWER-the closer to the nucleus the electron is, the more attraction there is and as a result it slows down faster. More energy is transferred to the xray and it has a higher energy as well. If the electron is far, it wont slow down as much, it will lose less energy and will result in a low energy electron. what is the cathode filament made of? - CORRECT ANSWER-Tungsten bremsstrahlung interaction - CORRECT ANSWER-99% heat, 1% x-ray aka braking radiation, cathode electrons hit anode electrons. Electron that are closer to the nucleus slow down more and lose more energy but create higher energy electrons. Electrons that are farther away slow down less, lose less energy and create low energy x-rays. They retain enough energy to keep having more interactions (electrons are more likely to hit the outer rim of the anode) characteristic interactions - CORRECT ANSWER-made 2 ways 1)cathode electrons hit anode electrons 2) PE effect from x-ray to electron interactions which interactions occur in the tube? - CORRECT ANSWER-bremsstralung what interactions occur in the body? - CORRECT ANSWER-PE, Compton, Coherent scatter what happens when we increase KeV? - CORRECT ANSWER-the chance of Compton effect increases, and the ratio between CS and PE also increases equations for frequency and wavelength - CORRECT ANSWER-c= speed of light= 3x10^8 m/s Hertz= cycles/s frequency = speed of light/ wavelength v = c/ upside down Y equation for energy - CORRECT ANSWER-E= hv h= 6.62 x 10^-34 Js = 4.15 x 10^-15 eVs 1 eV= 1.6 x 10^-19 Js quality - CORRECT ANSWER-overall energy of the beam increase mAs= identical quantity increase kVp= increase quality increase filtration= increase quality quantity - CORRECT ANSWER-the amount of x-rays, this is directly proportional to mAs primary radiation - CORRECT ANSWER-x-ray beam after it leaves the x-ray tube and before it reaches the object remnant radiation - CORRECT ANSWER-radiation resulting after the x-ray beam exits the object inverse square law - CORRECT ANSWER-I1/I2 = D2^2/D1^2 fundamental properties of x-rays - CORRECT ANSWER-1) EMR travel in waves at the speed of light in a certain direction in a straight light 2)can interact with matter wave particle duality tissue weighting factors - CORRECT ANSWER-relative sensitivity , Wt -can be used to convert partial radiation to whole body dose radiosensitive factors - CORRECT ANSWER-oxygenation of cell and cell cycle Bergonie-Tribondeau law - CORRECT ANSWER-cells that are rapidly dividing , undifferentiated and have a long mitotic cycle are more sensitive to radiation LET - CORRECT ANSWER-linear energy transfer alpha, protons = high LET xrays and electrons= low LET Wr - CORRECT ANSWER-radiation weighting factor ; difference in biological damage from different types of ionizing radiation It is the same thing as RBE and Q non-threshold - CORRECT ANSWER-all dose levels are potentially harmful ( stochastic) threshold - CORRECT ANSWER-there is a radiation level when no effect can be