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ChiroBoards2:XrayPhy
ChiroBoards2: Xray Physics/Production
| Question | Answer |
|---|---|
| xray tube inside a protective housing made of __________? | lead |
| xray tube consists of two electrodes called the ___________ and _________? | Cathode and Anode |
| This consists of a large filament, small filament and a focusing cup | Cathode |
| serves as a source of electrons in the production of xrays | filaments |
| filament is made from | tungsten |
| Occurs when a current is applied to the filament | Thermionic Emission |
| What controls the quantity of electrons (mA) emitted from the filament? | temperature |
| What does the number of electrons determine? | the number of x-rays created |
| What determines mA? | Temperature |
| Where does thermionic emission occur within? | the focusing cup/filament cup |
| The positive electrode in the xray tube | the anode |
| what is more common; stationary or rotating anode? | rotating anode |
| why does the anode rotate? | to dissipate the heat generated |
| exposed area of the tungsten target on the anode | focal spot |
| what determines the focal spot? | size of the filament |
| smaller filament = __________ detail: better/worse? | better detail |
| Beam Hardening aka | Line focus principle |
| Beam Hardening: smaller the target angle, the _____________ the effective spot | smaller |
| Stream of electrons narrows down to an effective beam | Beam hardening |
| mA = | Milliamperage |
| Heats the filament causing a boiling off of electrons | Milliamperage |
| More Current = ____________ radiographic density : More or Less? | MORE |
| Overall blackening on film: relates to? | density |
| structures that produce more blackening on the film | Radiolucent (more black) |
| structures that produce less blackening on the film | Radio-opaque (more white) |
| MAS and Density: what type of relationship? | Directly proportional |
| How to change blackness on a film? | Change the MAS |
| Increased MAS = | More film exposure / darker |
| % of minimum change needed to see a minimum change in density on the film. | 30% |
| If mAs is doubled, the density is_______________ | doubled |
| the force applied to accelerate the electrons from the cathode to anode at the time of exposure. | Kilovoltage (kVp) |
| Wavelength and frequency: what type of relationship? | inverse relationship |
| low kVp =__________ energy= ____________ penetration | low energy; weak penetration |
| high kVp = __________ energy= ___________ penetration | high energy; strong penetration |
| Difference in density between two structures | contrast |
| kVp and Contrast: what type of relationship? | kVp controls contrast, but they are inversely related. |
| low kvp = _______ contrast | high contrast |
| High contrast = short scale (low or high kvp?) | low kvp |
| sharp differences in dark and light area; "black and white" film = low or high kvp? | low kvp |
| Good for bone film: low or high kvp? | low kvp |
| less scatter but more patient absorption: w/ higher or lower kvp | lower kvp |
| high kvp = ______ contrast | low contrast |
| low contrast = long scale (low or high kvp?) | high kvp |
| more shades of grey (soft tissue film) = low or high kvp? | high kvp |
| produces more scatter but less patient radiation absorption : low or high kvp? | high kvp |
| 15% rule = To lower contrast = | Increase kvp by 15%, and decrease MAS by 50% |
| 15% rule = To increase contrast = | Decrease kvp by 15% and increase MAS by 50% |
| How is density affected by the 15% rule? | increase in kVp will double overall density on film and decrease in kVp will cut density in half. |
| Denser tissue absorbs _______ x-rays, while less dense tissues transmits _______ x-rays. (more or less?) | more; more |
| Gas = density? | black |
| Fat = density? | black |
| Muscle, water, and soft tissue = density? | gray |
| Bone and metal = density? | white |
| This effect given because the rotating target is angled, thus producing a varied intensity. | Anode Heel Effect |
| Intensity of x-ray is greater on the _________ side when compared to the _________ side. (anode or cathode?_ | cathode ; anode |
| Because of the Anode heel effect, when x-raying a foot, would you aim the x-ray tube so the cathode was pointed at the toes or ankle? and why? | ankle, because it's thicker |
| Because of the Anode heel effect, when x-raying a foot, would you aim the x-ray tube so the anode was pointed at the toes or ankle? and why? | Toes, because it's thinner |
| Anode Heel Effect: Anode side = less or more x-ray? | less x-ray |
| Anode Heel Effect: Cathode side = less or more x-ray? | more x-ray |
| Anode Heel Effect: Anode side = smaller or larger effective focal spot? | smaller focal spot |
| Anode Heel Effect: Cathode side = smaller or larger effective focal spot? | larger focal spot |
| Anode Heel Effect: Anode side = more or less detail? | more detail |
| Anode Heel Effect: Cathode side = more or less detail? | less detail |
| Anode Heel Effect: Anode side = use thinner or thicker body part? | Thinner |
| Anode Heel Effect: Cathode side = use thinner or thicker body part? | Thicker |
| Increase FFD = ________ Detail (increased or decreased?) | increased |
| Focal film distance, aka? | Source Image Distance |
| FFD represents what? | length of space from the focal spot (or tube) to the recording medium (or film) |
| As you __________ the FFD, the image gets smaller and more clear. (increase or decrease?) | Increase |
| As you _________ the FFD, the image gets larger and blurrier. (increase or decrease?) | Decrease |
| Intesity of radiation varies inversely with the square of the distance from the source. = what law? | Inverse square law |
| If a 40 inch FFD is doubled to an 80 inch FFD, the intesity of the radiation is _______ the amount of the intensity at 30 inches. | one quarter the amount |
| If a 40 inch FFD is increased to 80 inches FFD, how much must the radiographer increase (or decrease) MAs in order to maintain the same amount of film blackening | Increase MAs 4x |
| Double the Distance = __________ the radiation (amount?) | one fourth the radiation |
| Half the Distance = ________ the radiation | 4x the radiation |
| What piece is hit by the x-ray, causing fluorescent salts to change x-ray photons into visible light photons? | Intensifying Screen |
| What does the Intensifying Screen do to help the patient? | Exposes the film and decreases patient exposure |
| Large Crystals (more light) works quickly and yields _________ detail. (more or less?) | less detail |
| Faster screens = _________ contrast = ___________ scale | Higher contrast ; Short Scale (less patient exposure) |
| Small Crystals (less light) works slowly and yields _________ detail. (more or less?) | more detail |
| Slow screens = _________ contrast = ___________ scale | Lower contrast; Long Scale (more patient exposure) |
| Intensifying screens ________ density on the film (increase or decrease?) | increases density |
| Picture made by the useful beam | Umbra |
| Blurry halo parts of the image (unsharpness) | Penumbra |
| This is caused by having the tube too close to the film (Short FFD) | Penumbra |
| This is caused by having the patient too far from the film (long OFD) | Penumbra |
| This is caused by having too big a filament on the cathode, making the focal spot too big | Penumbra |
| Penumbra is caused by 3 things: | Too short a FFD; Too long an OFD ; Too big a filament on the cathode |
| OFD stands for | Object Fim Distance |
| Distance between patient and film is called | Object Film Distance (OFD) |
| Increase OFD = (does what to the image?) | makes it bigger and blurrier (more penumbra) |
| Decreased OFD = (does what to the image?) | makes it smaller and more clear (better detail) |
| The pressure exerted by the film holder as it encloses the x-ray film = | Screen Fim Contact |
| Best test for screen film contact = | The wire-mesh test |
| Poor screen film contact does what to the image? | reduces its sharpness |
| Two types of distortion = | Size and Magnification |
| What types of radiation occurs when x-rays strike an object? (3) | Scattered, Absorbed, or Penetrated |
| Scatter radiation can be reduced by using one of the following = (4) things | Grids; Air Gap Technique; Collimators; Filters |
| A device of alternating strips of lead and spacer material | Grid |
| Grids are placed between what two objects? | the Patient and the Film |
| How does the grid improve the quality of the radiograph? | absorbs scatter radiation |
| When using a grid, what must be increased to maintain density? | Exposure factors |
| Explain Grid Ratio = | The height of the lead strips : to the distance between the strips |
| What is the grid ratio in a chiropractic office** ? | 12:1 |
| What is the air gap distance between the patient and the film? | 6-10 " (example = lateral cervical view) |
| The distance between the body part and the film causes scatter radiation to diverge away from the film. What is this technique called? | Air-Gap Techinque |
| Limits the size of the bean to the size of the body part you need to capture on film = | Collimation |
| What is the best way to reduce scatter radiation to the patient, as well as to the film? | use collimation |
| this process is the preferential removal of low energy photons = | Filtration |
| Filtrators are usually made of = | Aluminum |
| Used to identify irradiation of patients and measures the radiation energy absorbed = | Radiation Absorbed Dose (RAD) |
| This unit is typically applied to occupationally exposed persons | Radiation Equivalent Man (REM) |
| How is REM measured on radiation workers? | by a photosensitive badge worn on the collar |
| 1 RAD = ____ REM | 1 REM |
| The number of REMs a person can get a lifetime without getting radiation poisoning = | Maximum Permissible Dose (MPD) |
| What is the safe REM (or RAD) amount to have per year? | 5 REMS (RADS) |
| Bremsstrahung aka? | Braking Radiation |
| Majority of useful beam and interacts with the target nucleus = (type of radiation?) | Bremsstrauhlung Radiation |
| A high intensity electron hits an inner shell electron which is knocked out of position in orbit. An out shell then fills its spot. = (type of radiation?) | Bremstrauhlung radiation |
| Primary form of scatter = (type of scatter radiation) | Compton Scatter |
| a moderate energy x-ray knocks out an outer shell electron which causes a loss of energy = (type of scatter radiation?) | Compton Scatter |
| Classic Scatter, aka's (2)? | Thompson Scatter ; Coherent Scatter |
| A low energy x-ray that changes direction with no energy loss and contributes to film fog = (type of scatter radiation?) | Classic Scatter |
| A low energy photon is absorbed by the subject creating a latent image on the film = | Photoelectric effect |
| Quantum Mottle, aka? | Radiographic Noise |
| Faster screens produce _________ quantum mottle = (more or less?) | more quantum mottle |
| What will decrease radiographic noise in regards to altering MAS and KVP? | High MAS and low KVP will decrease radiographic noise |
| This is caused by having too big a filament on the cathode, making the focal spot too big | Penumbra |
| Penumbra is caused by 3 things: | Too short a FFD; Too long an OFD ; Too big a filament on the cathode |
| OFD stands for | Object Fim Distance |
| Distance between patient and film is called | Object Film Distance (OFD) |
| Increase OFD = (does what to the image?) | makes it bigger and blurrier (more penumbra) |
| Decreased OFD = (does what to the image?) | makes it smaller and more clear (better detail) |
| The pressure exerted by the film holder as it encloses the x-ray film = | Screen Fim Contact |
| Best test for screen film contact = | The wire-mesh test |
| Poor screen film contact does what to the image? | reduces its sharpness |
| Two types of distortion = | Size and Magnification |
| What types of radiation occurs when x-rays strike an object? (3) | Scattered, Absorbed, or Penetrated |
| Scatter radiation can be reduced by using one of the following = (4) things | Grids; Air Gap Technique; Collimators; Filters |
| A device of alternating strips of lead and spacer material | Grid |
| Grids are placed between what two objects? | the Patient and the Film |
| How does the grid improve the quality of the radiograph? | absorbs scatter radiation |
| When using a grid, what must be increased to maintain density? | Exposure factors |
| Explain Grid Ratio = | The height of the lead strips : to the distance between the strips |
| What is the grid ratio in a chiropractic office** ? | 12:1 |
| What is the air gap distance between the patient and the film? | 6-10 " (example = lateral cervical view) |
| The distance between the body part and the film causes scatter radiation to diverge away from the film. What is this technique called? | Air-Gap Techinque |
| Limits the size of the bean to the size of the body part you need to capture on film = | Collimation |
| What is the best way to reduce scatter radiation to the patient, as well as to the film? | use collimation |
| this process is the preferential removal of low energy photons = | Filtration |
| Filtrators are usually made of = | Aluminum |
| Used to identify irradiation of patients and measures the radiation energy absorbed = | Radiation Absorbed Dose (RAD) |
| This unit is typically applied to occupationally exposed persons | Radiation Equivalent Man (REM) |
| How is REM measured on radiation workers? | by a photosensitive badge worn on the collar |
| 1 RAD = ____ REM | 1 REM |
| The number of REMs a person can get a lifetime without getting radiation poisoning = | Maximum Permissible Dose (MPD) |
| What is the safe REM (or RAD) amount to have per year? | 5 REMS (RADS) |
| Bremsstrahung aka? | Braking Radiation |
| Majority of useful beam and interacts with the target nucleus = (type of radiation?) | Bremsstrauhlung Radiation |
| A high intensity electron hits an inner shell electron which is knocked out of position in orbit. An out shell then fills its spot. = (type of radiation?) | Bremstrauhlung radiation |
| Primary form of scatter = (type of scatter radiation) | Compton Scatter |
| a moderate energy x-ray knocks out an outer shell electron which causes a loss of energy = (type of scatter radiation?) | Compton Scatter |
| Classic Scatter, aka's (2)? | Thompson Scatter ; Coherent Scatter |
| A low energy x-ray that changes direction with no energy loss and contributes to film fog = (type of scatter radiation?) | Classic Scatter |
| A low energy photon is absorbed by the subject creating a latent image on the film = | Photoelectric effect |
| Quantum Mottle, aka? | Radiographic Noise |
| Faster screens produce _________ quantum mottle = (more or less?) | more quantum mottle |
| What will decrease radiographic noise in regards to altering MAS and KVP? | High MAS and low KVP will decrease radiographic noise |
| Solution temps that are too hot will _________ density = (decrease or increase?) | increase |
| What processing factor brings out LATENT IMAGE by developing the exposed silver halide crystals? | Developer |
| Reducer/Developer = function? | Produces shades of gray and black |
| Reducer/Developer = chemicals? | Phenidone/ Hydroquinone |
| Accelerator/ Activator = function? | swelling of emulsion |
| Accelerator/Activator = chemicals? | NA+ carbonate |
| Preservative = function? | controls oxidation |
| Preservative = chemicals? | Na+ sulfite or K sulfite |
| Restrainer = function? | protects unexposed crystals |
| Restrainer = chemicals? | Potassium Bromide/Iodine |
| Hardener = functions? | controls swelling of emulsion |
| Hardener = chemicals? | Glutaraldehyde |
| What does Rinse do? (processing factor) | rinses away the exposed silver halide crystals |
| What does the Fixer do? (processing factor) | hardens the image, making it permanent on the film |
| FIXER = Acidifier/Activator = function? | Neutralizes the developer/ "stop bath" |
| FIXER = Acidifier/Activator = chemical? | Acetic Acid |
| FIXER = Clearing Agent = function? | Removes undeveloped Ag Halide/ "Hypo Solution" |
| FIXER = Clearing Agent = chemical? | Ammonium |
| FIXER = Hardener = function? | stiffens/ shrinks the emulsion |
| FIXER = Hardener = chemical? | Potassium Alum |
| FIXER = Preservative = function? | Maintains pH of fixer |
| FIXER = Preservative = chemical? | Sodium Sulfate |
| Washing does what? | Removes developer and fixer |
| What results from a film that has "Light Leak"? | Dark films |
| What results from a film with a developer temperature that is too hot? | Dark films |
| What results if a film is over exposed (too dark or too light?) | Dark films |
| What results if a film has developer temperature that is too low? | Light films |
| What results if a film is taken while the chemicals need replacing at the same time? | Light films |
| These color films result with inadequate developer = | Brown films |
| These types of films occur with inadequate fixer = | Milky films |
| These types of films occur with insufficient washing = | Greasy films |
| This can occur if you have an old film, hot developer, and contaminated chemicals = | increased fog |
| This is seen on the film if there is insufficient fixing = | soft emulsion |
| Store the film/cassette __________ to avoid pressure damage. = (vertically or horizontally?) | Vertically |
| This is produced when removing the film quickly from the cassette. | Static Electricity |
| What can static electricity do to a film when it is being removed from the cassette? | can cause black and branching lightning-like lines on the film |
| What does a rectifier do? | Changes AC to DC |
| What does a transformer do? | Steps up or steps down the power |
| What does a transducer do? | Changes one form of energy to another |
| What is the term used when a beam of radiation loses energy as it passes thru matter? | Attenuation |
| Why is blue or green tint added to the base of the x-ray film? | To reduce glare |
| Nail marks on fim appears as _________ : | creases |
Created by:
bglasman
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