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101 Cards in this Set
- Front
- Back
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what 2 things do you multiply to get thet mAs
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milliamperage and exposure time
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what does KVP do in relationship to the x-ray
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causes electrons to move from the cathode to the anode faster increasing the force of the collision with the target; results in a shorter wavelenght and more penetrating power
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which example is the most ideal and why
300mA at 1/60 sec=5mAs 200mA at 1/40sec=5 mAs 100mAat 1/20 sec=5mAs |
300mA at 1/60 sec=5mAs because its the higher mA with the shortest exposure time
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what are the layers of the film
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a thin protective layer( clear gelatin)
an emulsion( containing finely precipitated sliver halide crystals in a gelatin base) and a polyester film base |
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what is film latitude
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the films inherent ability to ayproduce shades of gre
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how should film be stored
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in a cool dry place with humidity of 40 to 60% away from strong chemical fumes and stored on end and not laid flat
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how much of the films radiographic density is caused by the intensifying screens
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95%
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what are 3 reasons for the thin waterproof protective coating over the phosphor layer on the intensifying screens
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to prevent static when loading and unloading
provides physical protection and provides a surfcace that can be cleaned |
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what should be used to clean intensifing screens
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a sort lint free cloth and an intensifying screen cleaner or warm water
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which of the following increases radiographic density
thicker body parts decreased KVp increased mAs increased density of the body part being radiographed |
increased mAs
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the primary exposure factor that controls scatter radiation is...
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KVp
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what do grids contain that controls scatter radiation
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Lead
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using santes rule what is the KVp setting for and area measuring 17cm
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74
17x2+40=74 |
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what phenomenon will occur when a long bone such as the femur is not parallel to the film when being radiographed
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foreshortening
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high subject contrast will increases or decrease radiographic contrast
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increase
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what are the 2 most common reasons for poor radiographic detail
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patient motion and the penumbra effect
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list the least dense to the most dense tissue
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air, aft, water or muscle, bone, and metal
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what are the 3 factors a diagnostic radiograph must record
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the size, shape, an location of the anatomical structures of the patient
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when does foreshortening occur
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when the object is not parallel to the recording surface
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increased___equals increased scatter radiation
mA mAs KVp mass |
KVp
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what factors do radiographic contrast depend on
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subject density
kvp level film contrast film fogging |
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what is subject density
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ability of the different tissues to absorb x-rays
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what settings can you change to lengthen or shorten radiographic contrast
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KVp
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what is grid ratio
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the relationship between the hight and width of the lead strips
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what is the offical name of the bucky system
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potter bucky dialhragm
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film fogging is an artifact that occurs before or after radiographic processing
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before
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a black irregular border on one end of the film is caused by light exposure before or after radiographic processing
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before
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what could be the cause of white areas on a film
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contrast medium on the patient table or cassette
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a black irregular border occuring on multiple sides of the film is caused by...
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felt damage on the cassette
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increased radiographic density with poor contrast occurs when
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the film was developed with chemicals that were too hot
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good radiographic density with poor contrast occurs when
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low-grade light leaks in the darkroom
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defined areas of decreased radiographic density occurs because
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air bubbles cling to the film during development
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visible grid lines occur because
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FFD is not in the range of the grigs focus
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defines white lines the lenght of the film occurs because...
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a damaged automatic roller is causing scratches
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the entire film being clear is caused by
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no exposure to the film
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what is the ideal patent for developing a technique chart
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a 40kg dog thats is not under or over weight
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what measurement of the dogs abdominal region is i deal when developing and technique chart
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10 to 20 cm
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according to the technique chart rules if you start out at 10 cm ( 60 kvp) what should the kvp be for a 22 cm abdomen
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70 kvp (not sure)
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how much should be added for each centimeter increase above 100 kvp
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4
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what should the kvp and mAs settings be for the 3 trial exposures when developing a technique chart
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1.7, 3.3, and 5 mAs at 70 kvp
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what is the radiographic density relationship for kvp
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increase the kvp by 20%> double the radiographic density
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what is the radiographic density relationship for mAs
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halve the mAs. halve the radiographic density
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what would be the KVp value for a 29cm patient using a regular variable kvp chart
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11ocm
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what is the dry bench used for
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unloading and loading of the cassettes and film storage
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what is a darkrooms most important feature
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that it is light proof
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the darkroom should have adequate ventilation because
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fumes can cause film fogging, damage to the electrical equipment and health problems for staff
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cleanliness is important in the darkroom because
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dirt and haor from the countertops can fall into the cassettes causing artifacts
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what 2 things in the dakroom should be cleaned regularly
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hangers and floors
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when should labeling of the film take place
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either durung exposure or before processing
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what 8 things must a label include
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name of patient and client
name and address of the hospital date taken age, sex, and breed of the patient |
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where and how far above the film is direct lighting
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at least 48 inches and directed toward the workbench
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what is the developers main function
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to convert the sensitized silver halide crystals into black metallic silver
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what are the 5 steps to developing a film
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developer
rinse fixer rinse dry |
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what are the 3 basic types of of x-ray equipment
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portable
mobile stationary |
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what are portable x-ray units ideal for
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taking radiographs of extremities of large animals
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most portable x-ray machines have a fixed what
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mA
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a high volume practice would benefit from what kind of x-ray machine
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stationary
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with fluoroscopy where is the x-ray tube located
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beneath the table with constant x-ray production
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when can a mobile c arm be used
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during surgery
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what are the benefits of using high frequency technology
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decreased exposure times
less scatter radiation lower exposure factors smaller size easier servicability |
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what is a wavelength
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its is the distance a wave can move in the time it takes to complete one cycle
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a nanometer is...
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1 millionth of a mm
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who invented x-rays
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wilhelm conrad roentgen
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what percentage of heat is generated in the x-ray tube
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99%
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what is the charge on the cathode side of the machine
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negatively charged
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true or false
the target is made up of copper |
flase a tungsten alloy
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what does the mA control
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the amount of radiation that is produced
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as x-rays pass through materials they have the ability to do what
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cause some substances to fluoresce (emit visible light)
completely remove electrons from an atom leaving the atom positively charged cause chemical changes that can kill cells |
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which way do the electrons travel in the x-ray tube
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toward the anode
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what 4 effects can radiation have when it comes into contact with living tissue
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passes through with no effect
produces cell damage that is repairable produces cell damage that is not repairable kills the cell |
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doses of radiation are ___ over a lifetime
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cumulative
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what is the maxium permissible dose of radiation per year
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0.05 SV
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what conditions are considered a type of somatic damage caused by radiation
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cataracts and sterility
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what are sources of ionizing radiation
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primary beam
scatter radiation x-ray tube head fluoroscopy |
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what is the approved thickness of lead in PPE
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0.5mm
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what is the safest way to reduce radiation exposure to staff
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make sure only staff necessary to hold the animal are in the room
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scatter radiation depends on...
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the intensity of the beam
the composition of the structure being radiographed KVp level |
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what are ways to reduce radiation exposure
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fast film speed combinations and collimated beam
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name 3 alternative methods of restraint
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drugs
tape sandbags foam wedges |
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why is it necessary to angle the beam 20 degrees on a V/D lumbosacral view
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to open up the lumbosacral joint space
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what should the relationship be between the sternum and the vetebrae on a V/D view of the thoracic spine
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positioned so that the sternum and vetebrae are superimposed in a plane perpendicular to the table
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what would you want to do to a dog before taking a spinal film...and what would this prevent
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general anesthesia to prevent a false narrowing of the intervetebral disc spaces caused by muscle spasms
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where would you measure for a lateral thoracic vetebrae view
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at the highest point of the thorax
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where would you measure for a lateral lumbar film
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over the thoracic lumbar junction
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what does padding under the sternum on the spine on a lateral thoracic vetebrae film do and why is it important
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it positions the sternum and the spinous processes in a plane parallel to the table which superimposes the ribs over one another providing good visualization of the intervetebral disc spaces
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what are the landmarks on a V/D thoracic vetebrae film
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the thoracic lumbar junction- midway between the xiphoid and the last rib dorsal to the spine
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if an animal is radiographed in right lateral recumbency what marker should be used
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right marker (R)
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when taking a radiograph of the elbow what and how much do you want to collominate proximally and distally
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from the distal thrid of the humerus to the proximal thrid of the radius and ulna
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what position is the head pulled for a lateral shoulder joint view
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dorsally and caudal
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what is the most appropriate method to seperate a digit from the others in order to radiograph it separately while the limb is positioned naturally
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with tape
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when radiographing the radius/ulna what should you include proximally and distally
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the carpal and elbow joints
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how would a patient be positioned to isolate the scapula as much as possible
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lateral recumbency with the affected leg closest to the cassette
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the lateral view of the elbow requires that the unaffected limb be pulled...
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caudodorsally
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a radiograph of the metacarpus-phalanges requires that the beam to be centered over...
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the middle of the metacarpal bones
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what 2 structures of the skull do you want superimposed and how would you accomplish this
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the tympanic bulla and rami of the mandibles
by padding beneath the dependent mandilbe with rolled cotton or foam wedges |
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what 2 views do you always take for the skull
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lateral and V/D
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what direction does the manidible need to be pulled for the open mouth tympanic bulla view
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caudally
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what are the collimation points for a lateral skull
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tip of the nose
tp of the head base of the skull mandible |
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where is the film placed for an intraoral view
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a corner of the film is placed into the mouth as far as possible
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what position should the hard palate be in for a V/D skull
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parallel to the table
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what position does the hard palate need to be in for the frontal 90 degree rostro-caudal skull view
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perpendicular to the table
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