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129 Cards in this Set
- Front
- Back
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Atom |
contains protons, neutrons, and electrons |
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Nucleus |
Center of cell |
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Proton |
Inside the nucleus and contains a positive charge |
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Neutron |
Inside the neucleus and contains a neutral charge |
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Electron |
The rings of the nucleus and contains a negative charge |
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Describe electrons farthest from the nucleus |
They are harder to bind to the nucleus, making it easier to remove them. |
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Ionization |
When an electron is removed, there is an unbalance between protons and electrons |
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Matter |
Substance that makes up something physical |
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Energy |
ability to do work |
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Light |
Energy classified by wave length and wave frequency |
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UV Rays |
Past spectrum of light |
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Shorter wavelength = |
Higher Frequency |
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High Frequency = |
More powerful |
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Roentgen |
First to discover properties of radiation; Late 1800s |
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What are the laws of Electrostatics? |
Like charges repel, unlike charges attract, Inverse Square Law |
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Inverse Square Law |
the intensity radiation @ location is inversely proportional to the square of the distance from the source of radiation |
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Contact |
Able to shock someone |
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Friction |
Rub 2 things together |
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Induction |
Happens when it's using electrons to make electrical field happen i.e. lightning |
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Increased mA = |
Increased Density |
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mA |
Milli-Ampherage; controls the # of electrons |
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resistance |
reduces the amount of current flow |
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Potential difference |
electrons travel from one end to the other |
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Voltage |
used to denote strength of electron flow |
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Electric current |
the area that can be changed |
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What does the law state about the wall switch for X-ray production? |
it must be 5ft. off the floor and within reach of the X-ray machine in case the machine will not cut itself off |
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Stationary X-ray unit |
has a generator; have to have dedicated powerline |
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Portable X-ray unit |
All the same stuff as the stationary except smaller components |
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The 4 Must Haves for X-ray production |
1. Source of Electrons 2. Place for interactions of electrons 3. Way to speed up electrons 4. Obstacle free path |
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99% heat = |
1% X-ray production |
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Folding cup |
Holds Cathode and focuses electrons toward the anode |
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Filament |
Wire made of Tungston steel; heat it by mA and it boils off electrons |
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Negative Cathy is |
Positively Anoding |
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Anode on a portable unit |
target area is stationary and at an angle; the place for interactions of electrons |
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Anode on a stationary unit
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Large and round, like a fan, with an angle; rotates; a way to use the higher settings to dissipate heat |
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Heel Effect |
intensity of beam is stronger to cathode side |
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Focal Spot |
area coming off the target area; width of X-ray beam; dependent on the angle of anode |
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The larger the target area = |
better heat but the less focus |
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The smaller the focal spot = |
The greater the clarity of the beam |
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Why is there an oil layer on the outside of the glass? |
Help pull heat off to keep it from overheating |
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What does the KvP do? |
Speed up electrons to get them in the target area |
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How do we obtain an obstacle free path? |
By using a vacuum to get the air molecules out |
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Circuit Breaker |
Accepts mA up to certain amount |
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Direct/Alternating Current |
# of cycles/second of current |
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Transformers |
step up or step down |
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Rectifiers |
take the negative portion of wave and make it positive |
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Describe Step Up |
Takes 110 voltage and steps up to 220 kVp |
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Describe Step down |
Takes 110 voltage and steps it down to mA |
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Intensifying Screens |
the speed of radiation to light conversion by the luminescent phosphorous crystals |
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Calcium Tungstate |
30-40% efficiency; emits slight in blue spectrum |
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Rare Earth |
50-60% efficient; emits light in green spectrum |
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What is the purpose of an intensifying screen? |
reduce the amount of radiation that we need so it reduces mA required to produce radiograph and chance of motion screens have to have high level of x-ray absorption, X-ray to light conversion, and little to no afterglow |
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the greater the # of silver hilide crystals converted to metallic silver... |
the blacker the film will be, so when it's processed any unexposed silver hilide crystals will wash away |
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What does supercoat protect on film? |
emulsion |
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Base of film does what? |
gives stability to film absorbed by light and silver hilide and when exposed silver hilide converts to metallic silver |
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What can cause film fog and what is it? |
light, heat, radiation, chemicals; appears as dark area on film |
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higher mA = |
higher density but KvP can also affect the density as well as developing time, temperature of developer, and thickness or type of tissue radiographing |
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more tissue = |
lighter density |
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mAs controls what? |
# of X-rays available |
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KvP also affects |
contrast |
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Radiographic contrast |
mechanic variables used to enhance contrast |
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Density difference b/t 2 areas is primarily affected by what? |
KvP |
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Subject Contrast |
patient thickness and confirmation effected |
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contrast is affected by KvP primarily, but what else can affect contrast? |
scatter radiation, film type, and film fog |
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What does kvp govern? |
penetrating power of beam (quality) & gives the ability to penetrate tissue |
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What is Santes' rule |
KvP = 2x the thickness in cm + 40 (40 = SID- Source Image Distance or FFD - Focal Film Distance which is distance from the tube to the table) |
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2 questions to ask when evaluating a radiograph |
is it too light or too dark? Is there proper penetration? |
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What happens when increasing mA |
increase# of electrons meaning mA can affect intensity of X-ray beam and measure of quantities produced and reduces movement |
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What are the 3 commandments? |
1. X-ray unit calibrated by qualified person 2. must measure thickness correctly 3. must measure at correct spot |
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what are the manipulating technical factors ? |
1. kvp 2. ma 3. time |
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distortion |
elongation source of X-ray not perpendicular to cassette if taking radiograph of limb & not |
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magnification |
animal parallel to cassette but not touching |
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inherent filtration |
add when machine is installed i.e. oil on glass housing |
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added filtration |
built into machine from manufacturer
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What is the purpose of inherent filter and added filtration? |
help reduce useless scatter radiation |
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collimators |
can decrease contrast |
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collimator indicator |
lead plates that restrict the size of beam |
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collimator testing |
measure beam to make sure its' accurate |
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collimation decreases contrast and also helps reduce |
scatter radiation |
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what is scatter radiation |
non-image forming type of radiation that is scattered in all directions as a result of object in the path of the beam |
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Grid ratio |
relation of height of lead strips to distance between them |
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what are grids? |
device placed between patient and film and absorbs scatter radiation constructed of lead strips .5 mm thick |
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parallel grids |
lead is straight up and down |
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focused grids |
slightly angled toward center |
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grid focus |
criss-cross; made to work @ a set SID of 24-44 inches |
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Automatic processing |
helps reduce odor to a degree because the chemical containers remain covered during processing |
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X-rays |
forms of electromagnetic radiation similar to visible light but of much shorter wavelength |
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radiograph |
physical thing from X-ray |
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Darkroom layout |
large enough for processing equipment, clean and organized, 40-60% humidity, exhaust fan for chemicals, walls should be light colored |
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Integrity of darkroom |
light-tight; completely dark |
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safelight test darkroom |
not regular; emits light in color spectrum that will not affect our film; 15 watts or less; mounted 4 ft. or more from work surface |
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film identifiers |
labeled (must be), lead tape, photo identifier, lead label id., right and left markers; legally the radiograph must be labelled before or after exposure but before processing |
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viewing radiograph |
hang the correct way |
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lateral radiograph |
back of animal = top legs = bottom head = left tail = right |
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VD radiograph |
head = top rear = bottom right = your left left = your right |
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before manual processing |
stir the chemicals, check the temp. of chemicals, 68 F @ 5 minutes, clip corners hanged after drying |
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ALARA |
as low as reasonably achievable; as little radiation as possible |
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When are the effects of radiology seen? |
not until division DNA compromised or cause cell death |
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What are the 2 ways radiology can affect? |
malignancy and genetics |
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Somatic Cell Damage |
All things that occur in your lifetime; i.e. cancer, cataract, anemia, etc.` |
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Genetic Damage |
lifetime that will not show up for 2-3 generations |
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How much lead is in PPE for protection from scatter radiation? |
.5mm |
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RAD |
energy imparted by radiation to something |
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REM |
amount of radiation absorbed by tissue |
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TLD |
contains lithium fluoride |
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Lithium Fluoride |
undergo heat process and crystals will glow per amount of radiation exposed to |
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MPD |
Maximum permissible dose of radiation |
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What is the MPD |
5 REM per year is the allowance of those with experience and dosimetry badges/permission. .05 REM per year for someone off the street |
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What are the rules of positioning? |
Label according to direction of the beam; combine 2 terms to label correctly; lateral recumbency is labeled according to the side that is down; right and left are combined with other terms, M & L should go last (dorsomedial); rostral, caudal, and cranial go before other terms (caudoventral) |
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What is computerized tomography? |
CT scan; radiograph obtained in circular motion; used to view bones, organs, etc. |
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3D image of CT |
see entire 3D section; can even see inside the bone |
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What is the donut of a CT? |
gantry; inside the gantry is anode, cathode, and everything else making radiation |
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Describe radiation emitted in an ark projector |
it does a 360 degree rotation |
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Doing CT on animals |
animals must be anesthetized; symmetry is important; computer system is always in another room |
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Houndsville unit |
refers to brightness of contrast in the image |
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Use what to decide density? |
contrast |
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Raw data |
gantry to computer; can be placed on film |
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PAC |
picture archiving systems; means it is digital |
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SFOV |
Scan Field of View; # of detectors covered by the X-ray beam |
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DFOV |
Display field of view; equal or smaller to SFOV; increases the ability to resolve structures |
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Big Slice Thickness |
can miss something |
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Slice Thickness |
we can decide how thick; determines film/image resolution |
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Algorithm or kernel |
used to enhance structures; decide beforehand what to look at; this tells the machine the best setting according to what you're looking at |
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Multi-Slice Scanners |
multiple detectors; allows multiple images to be taken at a time |
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Scout Film |
looks like regular flat digital image; legs us see image beforehand to double check technique |
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Contrast studies with CT scans |
something to enhance structure so it comes out better; use IV compound such as iodine with these |
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What is CT excellent for, use-wise? |
trauma and bone type injuries and head stuff; can almost pinpoint where something begins and ends |
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pros of CT |
picture clarity; pinpoint |
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Cons of CT |
expensive, time consuming, anesthesia, a lot of radiation |
