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physics
physics exam 2
| Question | Answer |
|---|---|
| T or F? when an x-ray bean passes through matter, it undergoes attenuation | true |
| T or F? xray photon interaction with matter depends on photon energy | true |
| Photodisintegration and ___________ are X-ray interactions that are not relevant to the diagnostic imaging range | pair production |
| T or F? when the photoelectric effect is more prevalent, the resulting radiographic image will possess low contrast | False, high contrast |
| T or F? the incident X-ray photon energy must be less than the binding energy of the inner shell electron for the photoelectric effect to occur | Fale, more |
| T or F? coherent scatter is an interaction which occurs between very high energy X-ray photons and matter | False, low energy |
| T or F? an xray photon will scatter only once before it is completely absorbed by matter | False |
| T or F? photoelectric absorption results when an X-ray photon interacts with an outer-shell electron | False, inner shell |
| T or F? the type of interaction a photon will undergo depends on X-ray energy and atomic number of the material | True |
| T or F? the probability of a photon undergoing photoelectric absorption is dependent on Z3/E3. in other words, a higher energy photon will undergo less photoelectric absorption, and a higher Z material is more likely to have photoelectric absorption | True |
| The two primary forms of X-ray interaction in the diagnostic range are ___________, ______________. | Compton scattering and photoelectric absorption |
| An incident xray interacts with an atom without ionization during ____________. | coherent scattering |
| An outer-shell electron is ejected and the atom is ionized during _________________. | compton interactions |
| Which X-ray interaction involves the ejection of the K-shell electron? | Photoelectric absorption |
| The scattered X-ray from a compton interaction usually retains _________ of the energy of the incident photon. A. none B. little C. most D. all | C. most |
| K-shell binding energy increases with increasing ____________. A. mass density B. kVp C. atomic number D. mAs | C, atomic number |
| Attenuation is caused by __________. A. absorption B. scattering C. transmission D. both A and B | D. both A and B |
| barium is a good contrast agent because of its ____________. A. low atomic number B. high atomic number C. low density | B. high atomic number |
| High kVp technique reduces ________. A. patient dose B. differential absorption C. image fog D. all the above | A. patient dose |
| At energies below 40 keV, the predominant X-ray interaction in soft tissue and bone is _________. A. coherent scatter B. compton scatter C. photoelectric absorption D. photodisintegration | C. photoelectric absorption |
| Compton scatter is directed at _______ degree angle form the incident beam. A. 180 B. 90 C. 0 D. any | D. any |
| As kVp _______, the probability of photoelectric absorption _____________. (increases or decreases?) | increases, decreases |
| In __________ there is complete absorption of the incident X-ray photon A. photoelectric absorption B. compton interaction C. pair production | A. |
| If 5% of incident beam is transmitted through a body part, then 95% of that bean was _____________. A. scattered B. attenuated C. absorbed | B. attenuated |
| Classical scattering: A. is the same thing as coherent scattering B. includes rayleigh, thomson, and comptopn scattering C. is the interaction of low energy X-rays with matter D. A and C E. A,B, and C | D |
| T or F? xray quantity is a measure of the number of X-ray photons in the useful beam | true |
| T or F? xray quantity is numerically represented by the half-value layer | False, quality |
| T or F? an increase in kVp by 15% will cause a doubling in exposure, the same effect as doubling the mA or doubling exposure time | true |
| T or F? Kilovoltage controls only the quality of the X-ray beam | False, quality and quantity |
| T or F? the factors that directly affect X-ray quality are kV and filtration? | true |
| T or F? as mAs is increased, X-ray exposure will increase (directly) proportionally | true |
| T or F? the reciprocity law fails for exposures made at extremely short exposure times or extremely long exposure times | true |
| T or F? mAs equals the product of tube current and kVp (potential) | False, tube current and exposure time |
| T or F? filtration is the process of eliminating undesirable low energy X-ray photons by the insertion of absorbing materials into the primary beam | true |
| T or F? the primary reason for filtration is the elimination of photons that would cause increased radiation dose to the patient but would not enhance the radiographic image | true |
| T or F? the HVL is that amount of absorbing material that will reduce the intensity of the primary beam to one-half its original value | true |
| T or F? filtration that is a result of the composition of the tube and housing is often called compound filtration because it is part of these structures | False, inherent filtration |
| identify the three factors that affect X-ray emission and are under the direct control of the radiographer: | mAs, kVp, distance |
| T or F? copper is the most common filter material used? | False, aluminum |
| T or F? any filtration that occurs outside the tube and housing and before the image receptor is considered added | true |
| T or F? the percentage of photons attenuated (due to filtration) increase as photon energy increases | False, it decreases |
| T or F? not only does filtration reduce the patient exposure dose by eliminating low-energy photons from the primary X-ray beam, it also removes a portion of the useful beam | true |
| the two primary forms of X-ray interaction in the diagnostic range are ________________,_____________. | Compton scattering, and photoelectric absorption |
| Which of the following is not an interaction between X-rays and matter? A. photoelectric absorption B. compton scattering C. bremsstralung | C. |
| the energy of the ejected photoelectron in photoelectric absorption is equal to: A.. the difference between the photon and the binding energy B. the sum of the photon and the binding energy C. the binding energy D. the photon energy | A. |
| T or F? when an X-ray beam passes through matter, it undergoes attenuation | true |
| T or F? xray photon interaction with matter depends on photon energy | true |
| T or F? electrons that are closer to the nucleus are bound more tightly and require less energy to remove them form their position | False, they require more energy to remove them |
| T or F? one photon may scatter only once before it is absorbed completely by matter | False, it can scatter many times |
| When the photoelectric effect is more prevalent the resulting radiographic image will possess: A. greater resolution B. less resolution C. low contrast D. high contrast | D. high contrast |
| T or F? compton scattering occurs when an incident photon interacts with a loosely bound outer-shell electron, removed the electron from its shell, and then proceeds in a different direction as a scattered photon | true |
| T or F? photoelectric absorption results when an X-ray photon interacts with an outer-shell electron | False, inner shell |
| T or F? a photoelecrtic interaction is more likely to occur with an electron that is more tightly bound in its orbit | true |
| T or F? when the photoelectric effect is more prevalent, the resulting image will possess high contrast | true |
| T or F? radiography of the lumbar spine, pelvis, and hip have the highest ESE's | true |
| T or F? selection of the lowest possible kV consistent with image quality is the best method of using exposure factors to reduce dose | False, highest kV |
| the radiation intensity from a diagnostic X-ray unit will vary in: A direct relationship with the ___________. Directly with the square of the _______. inversely with the square of the ______. | mAs kVp distance |
| T or F? a photoelectric absorption interaction is more likely to occur with an electron that is more tightly bound in its orbit | true |
| T or F? pair production and photo disintegration are interactions that are not relevant to the diagnostic imaging energy range | true |
| T or F? the average primary beam photon has a keV energy of only about 30-40% of the kVp | true |
| T or F? if mA , time or mAs are increased, the result is a decrease in the amplitude of the emission spectrum | False, increase in amplitude |
| T or F? if kVp is changed, the result is no change in the number of higher-energy photons | false |
| How does added filtration affect the emission spectrum? __________ amplitude and shift to the ___________. | reduced amplitude and shift to the right |
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taylos84