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XR 101 Final Exam
XR 101 Final exam
| Question | Answer |
|---|---|
| 1. how does filtration reduce patient exposure? | by removing longer-wavelength photons |
| 2. what is the national council on radiation protection and measurements recommendation for the amount of total filtration? | 2.5 mm Al equiv |
| 3. the unseen image that is contained on the film, before processing is called? | the latent image |
| what are 4 essential elements required for xray production? | target, vacuum, electron source, high potential difference |
| what is the target of the xray tube made of? | tungsten |
| what is the term used to describe the radiation that is absorbed by matter? | attenuation |
| the radiation that exits the body in all directions and causes unwanted exposure on the film as well as anyone who is in the room is called what? | scatter radiation |
| 9. the device used to produce the high voltage needed for xray production is called what? | the transformer |
| 10. what is the smallest possible unit of electromagnetic energy called? | the photon |
| 11. the electrical current flowing in an xray tube is measured in what unit? | milliamperes |
| 12. electrons are made available in the filmanent by a process called? | thermionic emissions |
| 13. the greatest portion of the xray beam is made of what type of radiation? | Bremsstrahlung |
| 14. the penetrating power of the xray beam is controlled by controlling which varying factor? | kilivoltage |
| 15. which of the following functions involves the autotransformer? | kVp selection |
| 16. the intensity of the xray beam is greatest at the cathode or anode? | cathode |
| 17. if the mA is doubled, the xray photons emitted from the tube are doubled or halved? | doubled |
| 18. what material is used as the added filtration material in the xray tube? | aluminum |
| 19. which of the following supplies and controls the heat required by the xray tube filament for thermionic emission of electrons? | the filament circut |
| 20. which of the following is controlled directly on the xray control panel? | the mA |
| 21. xray tubes should undergo the warm-up procedure AGAIN after they have been idle for more than | 1 hour |
| 22. what is the principle source of scatter radiation in radiography | the patient |
| 23. tissue with less mass, such as adipose (fat) will absorb more or less radiation as compared to tissue with more denisty such as bone? | less |
| 24. true or false? scatter radiation has more energy than the primay xray beam? | FALSE!! scatter radiation has LESS energy! |
| 25. when the SID is halved, what happes to the intensity of the radiation in the field? | it is quadrupled |
| 26. when the SID is doubled, what happens to the intensity of the radiation in the field? | it is quartered |
| 27. when the SID is doubled, what happens to the size of the radiation field? | it is quadrupled |
| 28. when the SID is halved, what happens to the size of the radiation field? | it is quartered |
| 29. what particles are located in the nuclesus of the atom? | the protons and the neutrons |
| 30. when an electron is gained or lost, the atom is said to be _____? | ionized |
| 31. what image receptor speed will result in the lowest patient dose? | fast speed IR systems |
| 32. what is the primary purpose of using gonad sheilding during radiography? | reduce the likelihood of genetic effects |
| 33. what is the greatest cause of unnecessary radiation to patients that can be controlled by the xray tech? | repeat exposures! |
| 34. what are the primary factors of exposure? | mA, time, kVp, SID |
| 35. if the image is underexposed, which of the following changes in exposure factors should be used to correct the problem? | increase mAs |
| 36. higher kVp settings produce images with long-scale or short-scale contrast? | long-scale |
| 37. what is the term used to describe unwanted exposure to the film | fog |
| 38. of the following, which is most radiosensitive? nerve, blood, muscle, skin | blood |
| 39. at what kVp levels do compton interactions occur? | throughout the diagnostic kVp range |
| what are the 4 primary aspects of radiographic quality? | density, contrast, distortion, recorded detail |
| what is another name for size distortion? | magnification |
| what is the most effective way to reduce scatter radiation? | the use of a grid, or buckey |
| 43. if the size of the radiation field increases, what happens to scatter radiation fog? | fog increases |
| 44. which pathological condition would require a decrease in exposure factors? | osteoporosis |
| 45. how will the anode heel effect be seen on the image? | the final image will be darker on the cathode side of the image |
| 46. which quality factor will be most affected by angulation of the central ray, body part, or IR? | distortion |
| 47. patient motion results in an image with poor ___ ___ | recorded detail |
| 48. an image with an increased OID results in a final image with _________ | magnification |
| 49. motion results in an image with poor ___ ___ | recorded detail |
| 50. OID and magnification are directly or indirectly porportional? | directly porportional |
| 51. as OID increases, magnification ______ | increases |
| 52. contrast is primarily controlled by which radiographic factor? | kVp |
| 53. density is primarily controlled by which radiographic factor? | mAs |
| 54. mAs is the primary controlling factor of density or contrast? | density |
| 55. kVp is the primary controlling factor or density or contrast? | contrast |
| 56. what do we call the unsharp appearance of anatomical margins on a radiograph? | penumbra |
| 57. what are the 3 types of scatter radiation? | coherent compton photoelectric |
| 58. which type of scatter is also known as Thompson radiation? | coherent |
| 59. which type of radiation is also known as secondary radiation? | photoelectric |
| 60. which type of scatter radiation knocks out an outer-shell electron from it's orbit? | compton |
| 61. which type of radiation knocks out an inner shell electron? | photoelectric |
| 62. which rule states that the kVp may be altered to modify the appearance of the image by changing the scale of contrast | 15% rule |
| 63. true or false: the operator should always maximize their distance from the source of the radiation? | true |
| 64. what is the conventional unit of absorbed dose? | rad |
| 65. what is the conventional unit of radiation exposure? | roentgen |
| 66. what material is the cathode filament made of? | tungsten |
| 67. this type of grid has grid strips that diverge to follow the xray beam | focused |
| 68. which unit is used to express the total quantity of xrays in an exposure? | mAs |
| 69. what is the term for the distance from the tube to the film? | SID (source-image distance) |
| 70. what unit is used to measure radiation in air? | Roentgen (R) |
| 71. what unit is used to measure absorbed dose (D)? | rad |
| 72. what unit is used to measure equivalent dose (EqD) | rem |
| 73. what is the annual exposure limit for occupationally exposed workers | 5 rem |
| 74. what is the monthly limit to the embryo/fetus for a pregnant worker? | must not exceed 0.05 rem |
| 75. what is the total radiation limit for a 9 month period for a pregnant worker | 0.5 rem |
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