Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
rad test 2
| Question | Answer |
|---|---|
| what is scatter radiation | another factor that can affect the image quality |
| how can prevent backscatter | place the cassette on a sheet of lead or using a cassette that have a thin backing of lead |
| what is a grid | a device that is placed between the patient and the radiographic film that absorbs non-imaging forming x-rays |
| what is a grid made out of | alternating lead strips and spacer material which consists of fibre, aluminum or plastic |
| what is a pseudo focused grid | parallel strips perpendicular to the focus of the grid |
| what is the focused grid (more probable) | lead strips angled that they focus at the centre point of the grid |
| what is the focal point | the centre on a lead strip where the beam is centred under |
| what is grid focus | distance from the grid to the source of radiation |
| what is it called if the grid is not used properly | grid cutoff |
| 4 reasons for grid cutoff | 1. focused grid upside down 2. improper centring of the x-ray tube over the grid 3. tilting the tube head laterally or tilting the grid 4. grid not in the focal range |
| what will an effective grid provide | reduce the amount of scatter seen on a finished radiograph without showing gridlines |
| True of false: the closer the lead strips are placed and the thinner they are, the less they are detected on a rad | true |
| what determines the grid efficiency | height, thickness, and number of the lead strips |
| what is the grid ratio | difference between the heights of the lead strips compared to the amount of space between 2 strips |
| as the grid ratio increases the ___________ also increases | efficiency |
| does the grid absorb the secondary radiation or just the primary beam | just the primary beam |
| Santes rule is defined as | a formula used when creating a technique chart to estimate the appropriate kVp |
| what is the santes rule equation | 2 x tissue thickness (cm) + FFD (40) + grid factor = estimated kVp |
| when to utilize a grid | when the patients anatomical area measures over 10 cm |
| when not to utilize a grid | when the patients anatomical area measures less then ten, except in cats |
| why do we still utilize a grid for felines | prevent scatter radiation hitting the film and causing film fog |
| what are technique charts useful for | obtain diagnostic images in a quick and consistent manner |
| what does a technique chart help avoid | retakes, saves clinic money, less film, less chemicals and less exposure |
| what factors are included when making a technique chart | -speed and brand of film -speed of screens, type of cassettes and ages -FFD -type of grid and ratio -tube rating chart -developer and fixer solutions |
| True or false: separate technique charts should be created for different anatomical regions and species? | true |
| what are the 6 steps to creating a technique chart | 1. select a patient 2. calculate the kVp for that region 3. select the mAs 4. create a mAs matrix based on machine 5. take exposure 6. create technique chart |
| what is the average size of an animal when selecting one for your technique chart | medium size, 18-20kg |
| when selecting the mAs is it suggested to use lower _______ (increased contrast) and high ____________ (decreased time) | kVp, mAs |
| when selecting the mAs the thorax requires _______ to ________% less than the abdomen and the pelvis will require ________% more mAs | 50-75% 75% |
| what is a latent image | an invisible image on the x-ray film after it is exposed to ionizing radiation |
| what is radiographic film | a record of remnant radiation |
| Layers of x-ray film | -protective coating -emulsion -adhesive -base -adhesive -emulsion -protective coating |
| what are the crystals called inside the emulsion layer of a film | silver halide |
| what is film latitude | number of shades of grey |
| 3 basic film groups | 1. fast film (ultra-speed) 2. medium film (standard speed) 3. Slow film (high detail) |
| what are intensifying screens | sheets of luminescent phosphor crystals bound together |
| layers of a intensifying screen | FILM SIDE -protective coating -phosphor layer -reflective layer -plastic base -back seal CASSETTE SIDE |
| the speed of intensifying screens depends on | -crystal size -thickness of phosphor layer -efficiency of reflective layer -dyes in phosphor layer |
| 3 screen speeds | 1. slow 2. medium 3. fast |
| slow screen speeds | -ultra detail -optimum detail -takes a long time |
| medium screen speeds | -medium speed -low exposure -good detail |
| fast screen speeds | -high speed -less detail -reduced exposure -loss of fine detail |
| what does a blocker do | prevents the x-rays to reach that part of the film allowing for an identification label |
| how often should screens be cleaned | every 1-3 months |
| 3 qualities that constitute a good darkroom | clean, organized, lightproof |
| 3 steps of processing film | Developer, Fixer, Washing/Dryer |
| what colour should the developer be and how do you know if it is to be changed | weak tea, if colour changes to a dark coffee colour |
| why do we wash the film after the developer and fixer | - removes processing chemicals from the film |
| advantages of automatic processor | -minimize human error -produces good quality diagnostic radiographs -less repeats due to processing errors |
| all automatic processors consist of.... | film tray, developer, fixer, wash bath, dryer, rollers, basic gears, replenishing pumps |
| disadvantages of automatic processors | -chemicals are more concentrated and temperatures are higher |
| 3 methods of silver recovery | 1. metallic replacement 2. electrolyte recovery 3. chemical precipitation |
| what is safe lighting | a small-wattage light bulb and a special filter to eliminate the light from a specific colour spectrum |
| what are the 8 technical errors of xrays | -increased film density (too dark) -decreased film density (too light) -black marks or artifacts -white marks (artifacts) -grey film -distorted or blurred rad -linear artifacts -miscellaneous artifacts |
| what causes black marks on films for technical errors | -film scratches -static electricity -top of film black -defective cassette |
| what cause white marks on films for technical errors | -dirt or debris -crack in screen -contrast medium on a tabletop, skin or cassette |
| what are the 9 processing errors of xrays | -increased film density -decreased film density -fogged film -yellow rads -white spots -black spots -air bells -reticulation -brittle radiographs |
| what causes fogged film on rads | -light leak -improper safe light -over developed |
| what causes yellow rads | not left in fixing solution long enough |
| what causes white spots in rads in processing errors | -defective screen -debris on film |
| what causes black spots in rads in processing errors | -static electricity -scratches |
| what causes reticulation in rads | -solution have an uneven temperatures in the tanks -solutions not stirred in manual processing |
| what causes brittle rads | -drying time too high -drying time too long |
| what are the two types of digital imaging | 1. computed radiography (CR) 2. digital radiography (DR) |
| what is the difference between DR and CR | how the latent image is processed |
| what is the quality of the image related too | -resolution -image noise -pixel size and number -field of view |
| advantages of CR systems | -elimination of wet processing and processing chemicals -wide latitude -shorter wait times for images -environment advantage |
| disadvantages of CR systems | -sensitive to fogging and must be stored properly -extra pieces of equipment -plates susceptible to cracking |
| two main factors with producing and viewing the digital image | -algorithm -histogram |
| advantages of digital imaging | -improved contrast resolution -environmental advantages -shorter wait times to view images |
| disadvantages of digital imaging | -motion artifacts -insufficient views -safety concerns |
| what does DICOM file stand for | Digital imaging communications in medicine |
| what does pacs system stand for | picture archive and communication system |
| what is the primary function of a fluoroscopy | provide dynamic real time imaging of the anatomy |
| disadvantages of fluoroscopy | -radiation induced injuries -development of radiation induce cancer -higher doses of radiation |
| what is a CT scan used for | -technique that provides a distinct image of any selected plane throughout the body |
| benefits of a CT scan | -procedures is painless -can image bone -minimal side effects |
| disadvantages of CT scan | -increase of radiation exposure -expensive for the client -sedation required |
| what is a mammography used for | examine the breast tissue for early detection of cancer and other breast diseases |
| what does MRI stand for | Magnetic Resonance Imaging |
| what does NMRT stand for | nuclear magnetic resonance imaging |
| what does MRT stand for | magnetic resonance tomography |
| what is an MRI used for | visualize internal structures of the body in detail |
| advantages of MRI | -can image blood flow -non invasive -superior resolution |
| precautions of MRI | -magnet can pose health hazards -need ear protection |
| What is nuclear scintigraphy | -non-invasive imaging procedure that will provide information about the function of a specific organ but not anatomical details about the structure |
| how does nuclear scintigraphy work | -radio active agents are injected into blood stream -tracers are carried to the area of the body with the greatest blood flow -energy is given off in the form of gamma rays detected by a special camera |
| how long must the animal be quarantined for after being injected with a radioactive tracer | 12-72 hours |
| what is the endoscope used for | examine the mucosa of the esophagus, stomach, and upper intestines |
| what can the endoscope help diagnose | foreign bodies, ulceration, neoplasia, biopsies, inflammation |
| two types of endoscopes and what they r used for | rigid: colonoscopy flexible: bronchoscopes |
| what is a contrast study | radiographic procedure used to supplement or confirm abnormalities on survey radiographs |
| what does a contrast study help diagnose | help make a diagnosis when there is not enough contrast to visualize the body part |
| 2 types of positive contrast media | barium sulfate preparations (soft tissue) and iodine preparations (urinary tract, vessels) |
| procedure for barium sulfate test | 1. patient is fasted 2. patient is put on IV fluids 3. surgery rads are required (R/L LAT Abdomen and V/D) 4. rads are taken after administration of barium sulfate until diagnosis is made or it reaches the colon 5. 24hr rads may be warranted |
| what is negative contrast media | carbon dioxide gas absorbs few x-rays that tissue and has a lower specific gravity, therefore more radiolucent and provides a negative contrast |
| Define: acoustic shadow | occurs when a structure prevents the transmission of sound waves to greater depths so structures distal to the object are not seen |
| Define: echogenicity | the intensity in which a substance is able to reflect echoes |
| Define: anechoic | no echoes are detected |
| Define: hyperechoic | structures that produce bright white echoes |
| Define: hypoechoic | transmits only a few echoes and appears a grey colour |
| Define: isoechoic | returning waves of normal amplitude |
| Define: attentuation | a reduction of the intensity of transmission through a material due to absorption and scattering |
| Define: AFAST | abdominal focused assessment with sonography for trauma |
| Define: TFAST | thoracic focused assessment with sonography for trauma |
Created by:
jscott41
Popular Veterinary sets