ANSC 252 (Final Exam)
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Created by:
kaulurose6 Plus on December 6, 2011
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166 terms
Terms | Definitions |
|---|---|
 dosimeter | a device used to measure radiation exposure to personnel |
| penumbra | halo effect |
| anode | the positive charged electrode in the x-ray tube |
| cathode | the negative charged electrode in the x-ray tube |
| wavelength | the distance between two consecutive corresponding points on a wave |
| heel effect | decrease in energy of the beam on the anode side; caused by target angle |
| frequency | the number of cycles of the wave that pass a stationary point in one second |
| photons | bundles of energy, carried by the wave |
| focal spot | the area on the anode with which the electrons collide |
| filament | source of electrons |
| collimator | a device that is used to control the size of the beam |
| focusing cup | recessed area in the cathode, directs electrons toward the anode |
| tungsten | metal used in the filament, high atomic number |
| molybdenum | metal used for the target and focusing cup, poor heat conduction |
| copper | metal used in the cylindrical anode, efficient heat conduction |
| calcium tungstate | illuminates with blue light |
| emulsion | layer of radiographic film made of gelatin and suspended crystals |
| film latitude | the exposure range of film that will produce acceptable densities |
| nonscreen film | film that is sensitive to ionizing radiation |
| oblique | neither parallel nor perpendicular to the long axis of a body or limb |
| rare-earth phosphors | illuminates with green light |
| screen film | film that is sensitive to fluorescent light |
| silver halide | a compound including halogen, on radiographic film |
| source-image distance marks | ensures accuracy of SID, tape measure and carpenter's level |
| light field size | ensures that the light field determined by the collimator dials is accurate, steel tape measure |
| light field/x-ray field alignment | verifies that the x-ray field is actually going where the light indicates, nine pennies, loaded cassette |
| screen-film contact | ensures that the adhesive is holding the screens tightly, copper wire mesh, densitometer |
| uniformity of screen speed | determines whether screens have lost speed through wear and tear, all cassettes, densitometer |
| calibration | ensures that exposure factors are accurate, service person |
| sensitometry and densitometry | ensures that processing is optimized and providing the beat quality radiograph, film, sensitometer, densitometer, thermometer |
| fog test | assess any added density during processing, lightly exposed radiograph, timer, densitometer |
| proton, electron, neutron | list the three particles in an atom, put a + or - if it is positive or negative |
| source image distance | the distance between the tube and the film, our is 40 inches |
| radiographic density | the degree of blackness or darkness on a radiograph |
| grid | a device made of lead strips embedded in a spacing material, absorbs scatter |
| magnification | this increases the further you take the subject away from the film |
| stationary anode | found in smaller units, anodes able to withstand less heat |
| rotating anode | found in larger units, anodes able to withstand more heat |
| contrast | measurable difference between two adjacent areas |
| density | overall darkness of a radiograph |
| kVp | exposure factor that determines the penetrating power of the x-rays |
| mAs | exposure factor that determines the total number of x-rays produced |
| overexposed | the film is too dark, exposure factors must be reduced |
| PennHIP | an examination method for hip dysplasia requiring special certification and a distraction device |
| reticulation | mottled appearance due to variation in the temperature of the chemicals |
| underexposed | the film is too light, exposure factors must be increased |
| joint (radiograph) | should include some of the long bone proximal and distal |
| long bone (radiograph) | should include the joints proximal and distal |
| thorax (radiograph) | should be taken at peak inspiration which includes 1st rib to diaphragm |
| abdomen (radiograph) | should be taken at peak expiration which includes diaphragm to acetabulum |
| temperature | the key factor when processing film |
| arth- | word part meaning a joint |
| barium sulfate | insoluble, ideal for digestive tract studies |
| cyst- | word part meaning bladder |
| double contrast media | the use of both types of contrast media |
| iodine compounds | soluble, low viscosity, safe to inject IV |
| lower GI study | barium enema |
| negative contrast media | has a low atomic number |
| pneum- | word part meaning air |
| positive contrast media | has a high atomic number |
| radiolucent | appears black on a radiograph |
| radiopaque | appears white on a radiograph |
| upper GI study | contrast media introduced to stomach and small intestines |
| primary beam scatter leakage | List the three ways personnel are exposed to radiation |
| monthly | How often should the dosimeters be sent out for evaluation? |
| avoiding retakes | What is the number one way to reduce exposure to personnel? |
| true | there are many types of electromagnetic radiation including gamma rays, x-rays, and television waves |
| true | the tissue type that is most susceptible to ionizing radiation is rapidly dividing cells |
| true | the maximum permissible dose is determined by The National Committee on Radiation Protection and Measurements (NRCP), and is the same for all Americans regardless of occupation |
| false | radiation is safer in one large dose rather than in small doses |
| true | genetic damage by radiation manifests visibly in offspring |
| "splitting" the cassette | cover half the cassette with lead, collimate and shoot. Repeat for the other half of cassette. Used to minimize the extra use of x-ray film on smaller areas such as extremities which two views can be radiographed on one film |
| minimum of two radiographs (Lat and VD) | Describe the minimum required views when radiographing an area on the body |
| how the animal is positioned and the penetration of the radiograph | Tell me what you know about directional terms. |
| 95 5 | Approximately ____% of the exposure recorded on a film is due to light from the intensifying screen, ____% is from ionizing rays |
| artifact | anything that decreases the quality of the radiograph, resulting in difficult evaluation and interpretation |
| fixer | Yellowing on radiographs is due to one chemical, which one? |
| technique chart | provide a consistent method of choosing exposure factors |
| medium size dog 50lbs well-behaved | Describe the ideal animal to radiograph to create a technique chart |
| quality assurance | management portion |
| quality control | equipment function and image quality |
| 2 | Every increase in 1 cm, add ___ kVp |
| 3 | Over 80 cm, every increase in 1 cm, add ___kVp |
| double | When you exceed the kv level, subtract 20 kv and _____ the mAs |
| false | mAs and kVp affect the density, but the main exposure factor that affects contrast is kVp |
| true | The MPD for the entire body of occupationally exposed personnel is 0.05 Sv per year |
| false | Electromagnetic radiation with lower frequency has more penetrating power |
| false | Animal's cells are not as susceptible to damage from irradiation as human cells |
| true | The two people not allowed to assist in radiology are individuals under 18 and pregnant women |
| false | According to Sante's rule, the further you are away from the source of the x-rays the safer you are |
| true | When the electrons collide with the target, 99% of the energy produced is heat and 1% is x-rays |
| x-ray tube | x-rays are produced in the _______ |
| milliamperage | ________ controls the amount of heat applied to the filament |
| acceleration | The _______ of the electrons is controlled by kilovoltage |
| kilovoltage | _______, which determine the penetrating power of the beam |
| magnification elongation foreshortening | List and describe the three types of geometric distortion seen in radiography |
| magnification | subject moves farther from the film |
| elongation | source is not exactly perpendicular to the film |
| foreshortening | subject is not parallel |
| heel effect (advantage) | when radiographing areas with variable thickness, place the thicker part toward the cathode side |
| autotransformer | The high voltage (anode/cathode) circuit is comprised of two transformers. The _________ provides a predetermined (kV) amount of voltage to step up transformer |
| step up transformer | _______ which increases 110 or 220 volts to thousands of volts |
| step down transformer | The low voltage (filament) circuit uses a __________ to reduce the 110 or 220 to about 10 volts |
| VD/DV radiograph | the head should be at the top and the animal's left is on the viewer's right (shaking hands) |
| Lateral radiograph | should face the left, spine at the top |
| automatic processing (advantage) | faster, less time consuming the temperature for the chemicals are automatically set |
| film labeling | radiographs are legal documents include L or R marker for positioning include patient, client, hospital information |
| true | Our filing system has two digits for the year, and for digits for the sequence of the animal |
| true | Screen speeds are divided into three categories, and medium speed is most commonly used in veterinary medicine |
| false | The terms radiograph and x-ray are interchangable |
| true | One way to track issues with cassettes is to number them |
| true | To absorb backscatter, the backs of most cassettes are lined with lead |
| false | The proper way to store film is 10-15C, 40-60% humidity, horizontal |
| false | The area of interest should be as close to the film as possible to increase magnification |
| darkroom qualities | clean organized light proof |
| false | Sensitometry and densitometry should be performed daily to assess the x-ray tube |
| true | Technique charts are based in tissue thickness and anatomic parts |
| true | A wet haircoat can mimic pathologic lesions |
| true | Patient motion is the most common artifact in veterinary medicine |
| false | White marks on the film can be caused by static electricity |
| false | If a screen is scratched, there is no way to determine which one it is, so you must purchase new cassettes |
| true | Air is the easiest contrast media to use, but not the safest |
| true | Whenever possible animals should be fasted for 12-24 hours prior to radiographs being taken |
| false | All GI studies require an enema prior to radiographs being taken |
| false | If chemical restraint is required for radiography, general anesthesia is always ideal |
| true | The two causes for black lines on a radiograph are either grid problems or roller lines from the processor |
| reduce patient motion | chemical restraints fast times |
| grid measurements | 10 cm and up reduce fog from scatter with higher kVp |
| perforations | barium sulfate is not water soluble, so it is the medium of choice for GI studies. If a perforation is suspected, iodine should be used first. If negative then do barium. If barium enters the thoracic or abdominal cavity. It must be surgically flushed out within 6-8 hours of administration. But a perforation is more fatal than barium in the body |
| ascites obesity | List two patient conditions that require increasing the mAs by 50% |
| portable units | house calls, 20mA, 90kVp (may require longer exposure times) |
| mobile units | 100-300 mA, 120 kVp (heavy, cumbersome) |
| mounted units | specialty practices, 1000mA (mounted in ceiling, difficult to radiograph feet) |
| equine pelvis | general anesthesia is required |
| equine cervical spine | positioned along the ventral neck, a common mistake is to radiograph too far dorsally |
| equine limb | it may be helpful to elevate the opposite limb to prevent movement |
| avian and exotic radiographs | mA 300 1/40 low kVp with small increments plexiglass, add 2 to 4 kVp |
| large animal radiography (difference) | size posture |
| patient restraint (large animal) | allow the animal to sniff the machine and the cassette speak in a calm voice avoid sudden movements and loud noises an animal in a standing position is relatively unrestrained, so personnel and the x-ray machine are in more danger of being kicked |
| patient restraint methods (large animal) | twitch stocks sedation lifting the opposite limb general anesthesia |
| patient restraint (avian and exotic) | manual (should be avoided) physical (plexiglass, tape, ropes, sandbags) chemical (reduces stress, prevents thrashing) |
| ultrasonography | uses sound waves of about 2-18 million Hertz per second and converts the echos of those waves into an image |
| computed tomography | takes multiple cross section radiographs, puts the images together to form a full view of a cross section |
| nuclear scintigraphy | uses a radioactive material to evaluate function of an organ |
| ultrasonography (cont.) | piezelectric crystal oscillates and creates an ultrasound beam the sound wave interacts with tissues in the body, echos are received by the transducer |
| acoustic impedence | the relationship between density/stiffness of tissue and the velocity of sound within the tissue (determines the intensity of reflected sound) |
| echogenicity | the intensity of reflected echos |
| anechoic | no echos are detected (bladder) |
| hypoechoic | few echos are detected (blood) |
| hyperechoic | echoes produces are brighter than surrounding tissue (bladderstone) |
| ultrasonography transducer | 7.5 MHz (small dogs, cats, equine tendons) 5 MHz (medium to large dogs, equine reproductive) 2.5-3 MHz (large animal) |
| echocardiology | cardiac disease (doppler) |
| computed tomography (advantage) | is the ability to acquire information not available from radiographs, contrast studies, or ultrasound |
| CT (indications) | central and peripheral nervous diseases of the brain, spinal cord, and lumbosacral spine masses in the mediastinum, axillary region, and retroperitoneal space |
| nuclear scinitigraphy (cont.) | noninvasive procedure where a radioactive material is administered (IV, transcolonically, or aerosol insufflation), absorbed by a target organ, and the gamma emissions are measured by a gamma camera |
| NS (clinical application) | thyroid - detects "hotspots" of hyperactive areas in hyperthyroid cats bone - hot spots: increased remodeling activity (neoplasia, infection, trauma) cold spots: decreased activity (bone necrosis) liver - masses, billary obstruction, abnormal hepatic blood flow |
| digital radiography | the cassette and film are replaced by reusable image receptor (detector) the image is received the same way, but instead of exposing film, a digital plate is exposed that transforms the emitted light into an electrical image the image is converted in a computer and is viewed on a monitor |
| PACS | picture archiving and communication system (all computers and components used to capture, transfer, store and display medical digital information) |
| digital radiography (advantage) | kVp has little effect on the contrast (this can be adjusted with software on the computer) overexposure and underexposure are essentially a thing of the past (fewer retakes) time (no developing) image storage and transport (computer search and e-mail) cost (films, chemicals, maintenance, labor, better diagnostics) follow-up (comparing current/past radiographs is much easier) |
| digital radiography (disadvantage) | personnel training equipment cost |
| HIS | hospital information system (electronic medical records keeping system) |
| RIS | radiology information system (ideally communicates with HIS) |
| DICOM | digital imaging and communications in medicine (The American College of Radiology and the National Electrical Manufacturer's Association formed a committee to develop a compliance between different vendors that all images are transferable and safely read by all DICOM software) |
| indirect digital radiography | using imaging plates that must be read |
| direct digital radiography | convert energy directly into a digital signal |
| digital artifacts | CR plates are susceptible to cracking in the plate reader CR plates must be erased (fog, "cosmic rays") Uberschwinger effect (halo around orthopedic implants) plate upside down, grid cutoff, severe overexposure, motion, poor positioning |
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