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ExposuresEdna

Exposures Help

QuestionAnswer
Who discovered x-rays? Wilhelm Conrad Roentgen
When were x-rays discovered? November 8, 1895
What was the name of the first x-ray tube? Crooke's Tube
What were the problems with Crooke's tube? It was not a vacuum and it was not focused.
What was the name of the 2nd x-ray tube? Jackson Focus Tube
What were the differences between the Crooke's Tube and the Jackson Focus Tube? If focued the beam and had an inclined anode.
What was the 3rd x-ray tube? Coolidge Hot Cathode Ray Tube
What were the advantages of the Coolidge Hot Cathode Ray Tube? Consistant source of x-rays that could be duplicated. It was vacuum sealed.
What is the cathode made of? A spiral incandescent filament of tungsten wire.
Is the cathode negative or positive? Negative
How many filaments are in the cathode? 2. Small and Large
What does incandescent mean? Gives light.
What heats the filament? Electrical current
What determines the electrons that are sent to the filament and controls heat? mA- milliamperes
Is the anode positive or negative? positive
Where does x-ray production happen? Anode
What are x-rays? Striaking of matter by high speed electrons (bombarding of electrons) They are electromagnetic energy.
What are the differences between x-rays and light? X-rays have short wavelengths and can penetrate. Light has long wavelengths and can't penetrate.
What is wavelength? KVp
If you increase KVp what happens to wavelength? It becomes shorter. (more power)
Can x-rays penetrate material? yes
Do x-rays cause objects to flouresce (give light)? yes
Are x-rays visible? no
Do x-rays produce biological changes? yes. They stimulate or retard growth
Are x-rays ionized gas? yes (removing electrons from atoms forms ions)
Do x-rays travel in straight lines? yes
Is energy changed from on ion to another in an x-ray? yes
What is the normal light that we expect to see? Luminescent (good)
What is phosflourescent? After glow (bad)
What is the anode made of? Tungsten Atomic #74
How fast does the anode spin? 10,000 revolutions per min
Spinning anode goes from a focal spot to a ? focal track
Does a stationary anode have a focal spot or a focal track? focal spot
What sends electrons to the spiral filament on the cathode and warms the anode by spinning it? Rotor button
What sends the electrons to the anode? Exposure switch
What controls the amount of radiation produced? mAs milliamperes per second
If you increase mA what happens to heat? Increases
If you increase mA what happens to x-rays? Increases
If you increase s (seconds) what happens to heat? Increases
If you increase s (seconds) what happens to x-rays? Increases
What is power? KVp
What is tube current? KVp
What does Bremsstrahlung mean? Breaking radiation
Where does Bremsstrahlung occur? The anode
What is boiling off of electrons from around the filament? Thermeonic Emission
Some x-rays are totally absorbed by the anode? True or False true
Anode slows tube current to form x-rays. What is this called? Bremsstrahlung
Which is stronger? Bremsstrahlung or Characteristic? Bremsstrahlung
Where are Bremsstrahlung and Characteristic created? In the tube
How many x-rays make it out of the tube? 1/3
How many x-rays go away as heat? 95% 5% give x-rays
Which interactions happen closer to the nucleus? Bremsstrahlung interactions
Which type usually does not make it out of the tube? Charactaristic Radiation
Which type makes it to the patient? Bremsstrahlung
X-rays are polyenergenic. True or False True (they have many energies)
How much inherant filtration is in the x-ray tube? 1-1.5 mm
What accounts for inherant filtration? glass envelope oil in the tube
How much filtration is added by the manufacturer? 1-1.5 mm
What is added filtration made out of? aluminum
How much total aluminum filtration should there be? 2.5 mm (1-1.5 inherant + 1-1.5 added)
Added and inherant filtration get rid of what type of radiation? Characteristic
What type of radiation come out of the anode and directly down to the top of the patient? Primary radiation
What is it called before it interacts with the patient? Primary radiation
What type of radiation goes from the patient to the IR Remnant Radiation
What is it called after it interacts with the patient? Remnant Radiation
What passes through the patient unaffected? Primary beam
Rays that interact within the patient emit what type of radiation? Secondary and Scattered
What percent of the primary beam goes to the IR and interacts with nothing? 5%
What percent of the primary beam comes out as secondary radiation? 15%
What percent of the primary beam gets absorbed by the patient? 80%
From the 20% of the Remnant Radiation (after it interacts with the patient) how much of the beam exposes the film? 20%
What type of radiation most closely follows the direction of the original beam? Secondary Radiation (good)
What type of radiation has rays that go in all directions? Scatter radiation (bad)
What type of radiation gives color (density) that is not useful? scatter radiation (veil of density)
What is partial absorption of the x-ray beam? attenuation
What is it called when the beam is totally absorbed? absorption
What color will total absorption be on an x-ray? white
Why is an an x-ray beam that is absorbed white on the film? Because it does not make it to the IR.
What color is attenuation on the film? any where from gray to black
Greater absorption give greater subject contrast or lesser subject contrast? Greater
What is subject contrast? Subject contrast represents the differences in x-ray absorption in the body.
Is contrast the differences in the film or the patient? Film
Is subject contrast the differences in the film or the patient? patient
What gives lighter gray on the film? Higher attenuation or lower attenuation Higher
Is low contrast a long or short gray scale? long
Is high contrast a long or short grey scale? short
What is used to center your body part? Central Ray
What does SID mean? Source to Image Distance
What are other ways to say SID? TID- Target to Image Distance FID- Focal to Image Distance
What does OID mean? Object to Image Distance
How else can you say OID? OFD- object to film distance TFD- target to film distance FFD- focal to film distance
What is the primary unit used for the quantity of x-rays? R- roentgen
What is the exposure to the patient? RAD- radiation absorbed dose
What does RAD mean? Radiation absorbed does.
What is exposure to technologist? REM- radiation equivilent man
What does REM mean? radiation equivalent man
What are the exposure factors? mA, S, KVp
If you increase mAs, what happens to density? Increases
If you increase mAs, what happens to color? Increases
If you increase mAs, what happens to gray scale? nothing
If you increase mAs, what happens to contrast? nothing
If you increase mAs, what happens to quantity of x-rays? Increase
If you increase mAs, what happens to recorded detail? nothing
What protects the x-ray film? the cassette
Where do you put the film? Inside the screen
What kind of crystals are in the film? silver bromide crystals
What are the silver bromide crystals suspended in? gelatin
What is the most functional part of the film? emulsion
What do the silver bromide crystals give on the film? density
What does the blue tint in the gelatin do? helps with contrast on the final image
What protects the emulsion? T-coat (tough coat)
What attacks the silver bromide crystals that are fractured? Developer
What washes away the silver bromide crystals that are unfractured? Fixer
What washes away off all the chemicals? Wash tanks.. water
What is the last step to film processing? drying
What do x-rays do to the silver bromide crystals that they hit? fracture them
What type of film has emulsion on one side? Single emulsion
What type of film has emulsion on both sides? Double emulsion
Does double or single emulsion film have better detail? Single
On single emulsion film, what is the other side made from? polyesther plastic
Is the emulsion side of the film shiny or dull? dull
What is the image before processing film called? Latent Image (invisible)
What is the imnage after processing film? Manifest Image (visible)
What are x-rays that you can hold called? Static x-rays
Do you get more or less fractured crystals with thicker body tissue? Less
Does thicker body tissue result in more or less density on the film? Less
What are the layers of film? Base- supports the film Emulsion- silver bromide crystals gelatin blue tint Tough coat- on top of emulsion (t-coat) Adhesive layer- connects the layers
What are other names for focal spot? focal point focal track target
Where is the focal spot located? on the anode
How big is the focal spot? 1/2" square
How fast does the anode rotate? 10,000 revolutions per min
What is the focal spot called on a rotating anode? Focal track
Name the 2 types of anodes Stationary and Rotating
What is the anode made out of? Tungsten
Why is the anode made of Tungsten? High atomic # (74) high melting point good conductor of heat efficient producer of x-rays
Where is the filament mounted on the cathode? in the focusing cup
Is mAs quality or quantity? quantity
If you increase quantity, what happens to density? Increases
If you increase quantity, what happens to contrast? Nothing
What determines the size of your focal spot? quantity of beam
Which focal spot gives better detail? Small or Large? Small
Which focal spot can hold more electrons? Small or Large? Large
What is the only thing that focal spot size affects? DETAIL..... only detail
What does intensity mean in x-ray? DENSITY...
Does the x-ray beam increase or decrease toward the anode? decrease
Does the x-ray beam increase or decrease toward the cathode? increase
If you increase the focal spot what happens to detail? decreases
Do you get better detail with a small or large focal spot? small
The distinction between lines is? sharpness
What is the spreading of the edges of the image? penumbra
Which is the good part of the image umbra or penumbra? umbra
Do you want to minimize umbra or penumbra? penumbra
Do you get more penumbra with a large or small focal spot? Large
How does penumbra grow? Inward and outward... invading the spaces of the umbral image
Does OFD cause more or less penumbra? more.. OFD is same as OID
What is sharpness of detail? Penumbra and umbra
What is the size of a large focal spot? 1 mm to 2 mm
What is the size of a small focal spot? .05 mm to 1 mm
What has to grow to get magnification? penumbra and umbra
How does focal spot affect magnification? Not at all.. only affects detail
Is focal spot an electrical or geometrical factor? geometrical
What is the line focus principal? the actual stream of electrons is considerably wider than the projected focal spot
What does the actual focal spot determine? how many electrons
What does the projected focal spot determine? Sharpness
What is the angle of the anode bevel? 15 to 17 degrees
What gives better detail? an anode bevel of 17 degrees or an anode bevel of 45 degrees? 17 degrees.. the more toward vertical, the better the sharpness
Can the technologist change the anode bevel? no
A variation in x-ray intensity output along the longitudinal tube axis is called? Anode heel effect
With the anode heel effect, does the larger part go toward the anode or the cathode? cathode... (fat-cat)
In normal x-ray procedures do we put the head toward the anode or the cathode? anode
What reasons do we use the anode heel effect? 1. differences in body thickness 2. large focal spot 3. Short SID 4. larger film size
What body parts do we use the anode heel effect for? 1. T-spine 2. femur 3. feet 4. humerus
Do you have more or less divergence if you increase SID? less
What is the only portion of the beam that goes straight down? Central ray
Do you have more divergence at 40" or 72"? 40"
What is the Star Pattern Template Method used for? to determine focal spot deterioration
What is the Wisconsin Focal Spot Test Tool? It is similar to pentrometer and is used to evaluate where you see sharp lines.
What happens if you increase exposure time? density increase
What happens to contast if you increase mA? nothing
What are the primary factors for a good radiograph? mA s (time) KVp SID
What are the elctical factors? mAs KVp noise
What are the goemetrical factors? Shape distortion Size distortion Sharpness
Anything that we do are used is called? Technical factors
What gives the electical current in the beam? mA milliamperes
If you increase mA, what happens to the electrical current? increases
How does the intensity of the beam affect contrast? Intensity is density... Never affects contrast
If the quantity of the beam increases, what happens to the quality? nothing... quantity is density, quality is KVp
What does mAs directly affect? density
What does KVp directly affect? contrast
The use of many different combinations of mA and s to keep the same mAs, and maintain the same radiographic density refers to what law? The Reciprosity Law
What controls the intensity of the total exposure? total mAs
What does Quantum Mottle look like on an x-ray? salt and pepper
What causes Quantum Mottle? lack of density from too low mAs
What is the only way to compensate for Quantum Mottle? Increase mAs
What is responsible for bringing mAs to the film? KVp
Does detail come from electrical or geometrical factors? geometrical
Contrast cannot change unless what happens? The absorption rate between tissues change
If a film is overexposed, what should you adjust? cut back on mAs
What does scatter create on a film? fog
How much do you need to adjust mAs to compensate for an underexposed film that is not penetrated? you don't adjust mAs. underexposure caused from no penetration is due to KVp
When you have structural lines on the film do you have penetration? yes
Do you always want to use the longest time or the shortest time when taking an exposure? shortest
Why do you want to use the shortest time when taking an exposure? to reduce motion from the patient
What is the direct cause of motion? Patient movement
How do the electrical factors affect the geometrical factors? They do not affect them
What determines tube current? mAs
What is the overall blackening of the film? Density
How many shades of gray can we see on a static film? 32
How many shades of gray can we see on a computerized image? 256
How much do you need to increase mAs for a visual change in density? 30%
If you go from supine to prone, how much do you need to increase mAs? 50%
What happens to density if you increase by a factor of 2? it doubles
What is used to measure density on an x-ray? densitometer
What are odu's? Optical density units
How does KVp affect density? exponentially (it increases quickly)
What does KVp to in order to penetrate the body? It alters the wavelength
If you increase KVp, what happens to wavelength? it decreases
If you increase KVp, what happens to frequency? it increases
If you increase KVP, what happens to penetration? it increases
What is determined by absorption and attenuation levels? contrast
Does higher KVp result in higher or lower contrast? lower contrast
Do you increase or decrease KVp for a larger patient? Increase
What is the most important function of KVp? penetration of the x-ray beam through the body
What do we want to strive for in terms of contrast? The longest scale for the part
If a radiograph is overexposed and there are no whites, is it because of mAs or KVp? KVp
If a radiograph is overexposed and the are whites, is it because of mAs or KVp? mAs
If you increase mAs, what happens to patient dose? It increases
How much mAs do you need to correct the lack of KVp? No amount of mAs will compensate for the lack of KVp
What produces white on the radiograph? Bones
What produces black on the radiograph? Air
What is fat and other tissue cause on the radiograph? gray scale
If absorption levels change what happens to contrast? It also changes
Only a few x-rays are produced at peak KVp level. What is the average of the rest of the beam? approximately 1/3 of peak KVp
How much do you need to alter mAs to double density? by a factor of 2
How much do you need to alter KVp to double density? 15%
How much do you need to alter mAs for a visual change in density? 30%
How much do you need to alter KVp for a visual change in density? 5%
What kind of radiation most closely follows the direction of the original beam? Secondary radiation
Does scatter give any useful information on the radiograph? no
If you alter KVp do you change density or contrast? Both
If you alter mAs do you change density or contrast? density... mAs does not affect contrast
Do you need to increase or decrease KVp for Degenerative diseases? decrease
Do you need to increase or decrease KVP for Additive diseases? increase
What is the differences in intensity between one portion of the x-ray beam and another? Subject Contrast (subject contrast is patient contrast)
Which is more detrimental to the finished radiograph? Short or long scale contrast? Short (short scale is high contrast)
What are 3 things that affect subject contrast. Insufficient penetration alteration of the direction of the remnant beam extreme overexposure of the film
What is the #1 form of noise on a radiograph? Fog
What is noise? A type of distraction on your radiograph
Can a film be fogged without being overexposed? yes
How do you know if a film is fogged? There will be no whites on it
What does ALARA mean? As Low As Reasonably Achievable
What does ALARA refer to? patient dose
What combination of mAs and KVp do you want to use to minimize patient dose? High KVp and low mAs
What is the light we see come out of the view box is called? Tone value (tone value is the opposite of density)
Does the white area on a radiograph have high or low tone value? High
What is exposure latitude? the range between minimum and maximum exposure that gives a diagnostic radiograph. The margin for error latitude=leeway
If you increase KVp, what happens to exposure latitude? increase exposure latitude
Does high contrast give a wide or a narrow exposure lattitude? narrow
If you have a long gray scale, do you have a narrow or wide exposure lattitude? wide
In order to see an x-ray, you need light energies in the form of what? photons
What has a shorter wavelength and higher frequency? photons or light? photons
What is the differences between intensities? Contrast
Does fog affect detail? no.. only the visibility of detail
What type of matter can be penetrated by x-rays? radioluscent
What type of matter can not be pentrated by x-rays? radiopaque
Name a substance that is radiopaque barium
What causes size distortion on a radiograph? SID and OID
How do you minimize shape distortion? beam-part-film alignment
What happens if you angle the x-ray beam? elongation
What happens if you angle the anatomy? foreshortening
What happens if you angle the film? elongation
If you increase SID, do you get more or less magnification? less
If you increase OID, do you get more or less magnification? more
If you increase SID, do you get elongation or foreshortening neither... SID does not affect shape distortion
What is shape distortion? The difference between the shape of the real object and its projected image.
What ranges of density are diagnostically acceptable? .25odu's to 2.5 odu's
What is the most common artifact on an x-ray? Static (caused by friction)
What is the most common form of static? Tree Static
What are some forms of static on a x-ray? Tree Static Smudge Crescent Moon
What are all statics forms of? Artifacts
What is nthing that does not represent the true anatomy called? False image
What is the remnant beam called? Exit radiation
What is exit radiation composed of? Secondary and scatter radiation
How is a radiographic image created? By passing an x-ray beam through the patient and the interactions that occur within the IR
What is any radiation that goes through the patient without any interactions called? Transmission radiation
What color is transmission radiation on the film? black
What are the 3 aspects of tissue that determine attenuation and absortion, resulting in subject contrast? tissue thickness tissue density tissue atomic #
What interactions are complete absorption? Photoelectric Interactions
Which interactions occur with inner shell electrons? Photoelectric interactions and Thompson Interactions
Which interactions occur with outer shell electrons? Compton Interactions
What percent of scatter are Compton Interactions responsible for? 99%
What are other names for Compton Interactions? Incoherant and Modified
Which interactions have a slightly higher energy than binding? Photoelectric
Which interactions have a greatley larger energy than binding? Compton Interactions
Which interactions have less energy than binding? Thompson Interactions
What percent of scatter radiation comes form Thompson Interactions? 1%
What are the other names for Thompson Inter, actions? Coherant, unmodified and classical
What percent of remnant radiation is scatter? 75%
Is all scatter secondary radiation? yes
Is all secondary scatter radiation? no
What is the degree of blackness or darkness in an area of the image, determined by the amount of silver deposited on the film in that area? Density
What is the amount of light that is able to penetrate through an area on the film, or the area's translucency. The opposite of density. Tone value
What is the ratio of differences between two adjacent densities in the image? Contrast
What is the range or number of different densities in present in the image? The opposite of contrast. Gray scale
What is any unwanted, useless information recorded in the image which obscures the visibility of the desired image details. It includes fog, static and artifacts. Noise
A form of noise. A veil of useless density covering portions of the desired image. It is caused by randomly scattering radiation which carries no useful signal or image. Fog
What is the abruptness with which the edges of an image stop. More precisely, the lack of penumbra shadows at the edge of an image. Sharpness of recorded detail
What is the presence of penumbra, or the lack of sharpness, at the edges of an image. Blur
What is the partial shadow at the edges of an image, whereby its transition into the adjacent. Penumbra
What is the differences between the size of a real object being radiographed and the size of it projected umbral image (measured in all directions) Magnification
What is the differences between the shape of a real object being radiographed and the shape of its projected image, consisting of either elongation or foreshortening of the image? Shape distortion
What are those image qualities which directly affect the ability to see an image. They include density or tone value, contrast or gray scale and noise including fog? Visibility factors
What are those geometrical image qualities which directly affect the ability to discern the nature of the real object being projected onto the image. These include sharpness of detail, magnification and shape distortion. Recognizability factors
What is the ability to distinguish small adjacent details in the image as being separate from each other. It is controlled by both visibility and recognizability factors. Resolution
What is the total amount of diagnostically useful information resolved in an image. It is controlled by the combination of all visibility and recognizability factors. Radiographic Image Quality
Created by: Edna Bradley Edna Bradley on 2010-11-10



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