Term
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Definition
| PENETRATING ability of radiographs |
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Term
| What would happen if you increased kVP? |
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Definition
increases film blackness and contrast
higher kVp is more contrast-y |
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Term
| What would be your kVP setting for abdomen vs thorax? |
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Definition
HIGH for SOFT tissues
LOW for bone |
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Term
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Definition
| QUANTITY of electrons and film DENSITY (darkness) |
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Term
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Definition
| mA X time= INTENSITY of rads |
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Term
| An increase in distance decreases the intensity mas by __. |
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Definition
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Term
| What would be a mAS setting for abdomen vs thorax? |
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Definition
LOW for soft tissues
HIGH for bone |
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Term
| What are the different radiologic densities in order of increasing density? |
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Definition
| Air-->Fat-->water-->bone-->metal |
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Term
| If a film is too light what could be your problem? |
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Definition
| UNDERexposure, focal distance too long, speed of intensifying screen too SLOW |
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Term
| How could you fix a film that is underexposed? |
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Definition
| Double mA and add 10 to kvp |
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Term
| What could be some problems causing films to be too dark? How do you fix it? |
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Definition
OVERexposed, too high mA, too fast
1/2 mA, subtract 10 from kVP |
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Term
| In general, how could you make a film darker? |
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Definition
| increase mA, kVP, or time |
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Term
| What would be some causes of a GREY radiograph? |
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Definition
| SCATTER (THICK BODY PARTS W/O GRID), stored too hot/humid |
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Term
| What would cause yellow radiographs? |
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Definition
| fixation time too short, fixer exhausted |
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Term
| What would cause black dots on radiographs? |
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Definition
| develop solution falls on undeveloped film, films stick together so they touch fixer |
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Term
| What would cause white spots on radiographs? |
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Definition
| defective cassette screens, dust or grit on film surface, drops of fixer on film before development |
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Term
| What would cause blurring of radiographs? |
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Definition
| poor film-screen contact, pt movement, poor centering of primary beam |
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Term
| What would cause film distortion/magnification? |
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Definition
| focal film distance too long |
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Term
| What does an intensifying screen do? |
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Definition
| decreases the amount of radiation needed |
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Term
| What is non-screen film used for? |
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Definition
| intra-oral exams, dental, nasal, bony extremities, LONG exposure time with GREAT DETAIL |
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Term
| What kind of crystals are smaller and finer and give more detail? |
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Definition
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Term
| What is the developing order? |
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Definition
Developer solution (turns silver halide crystals into black metallic silver)
Rinse solution (stops development and prevents fixer contaimination)
Fixer (2x as long as developer to harden film, and prevents removal of crystals)
Wash bath (removes processing chemicals from film and prevents discoloration) |
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Term
| On dental rads, what is the PARALLEL technique used for? |
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Definition
| MANDIBULAR PREMOLARS/MOLARS |
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Term
| In dental rads, what is the BISECTING technique used for? |
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Definition
| MAXILLARY AND MANDIBULAR CANINES AND INCISORS |
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Term
| In dental radiography, what is the advantage of using the bisecting technique over the parallel technique? |
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Definition
| minimizes image distortion that come form inability to place film parallel to central axis of tooth, if you don't use this the tooth appears elongated or shortened |
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Term
| What artifact is seen on US when the beam hits highly reflective structures (such as stones) and forms a dark area beyond the structure (because the structure blocks US waves)? |
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Definition
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Term
| What artifact occurs when the US beam hits non-attenuating structures and emerging US beam will have higher intensity (brighter image)? |
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Definition
| acoustic enhancement/through transmission |
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Term
| Give an example of US artifact-acoustic enhancement? |
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Definition
GALL BLADDER
if you shine US thoruh gallbladder and liver, there is a bright beam below the gall bladder |
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Term
| What kind of US artifact happens when a comet tail with bright, parallel, evenly spaced lines occurs? |
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Definition
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Term
| Give an example of US reverberation artifact. |
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Definition
| US meets strong reflectors (gas or bone)....LUNGS |
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Term
| What is the A-mode on US? |
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Definition
| amplitude mode...1D display, returning echoes=SPIKES (intesnstiy show in HEIGHT of peaks) |
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Term
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Definition
| brightness mode, 2D imaging |
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Term
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Definition
| motion mode; echo, used for CMP or where you want accurate measurements, motion of the organ is shown as WAVY LINE across the screen |
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Term
| Why is it better to shave for US? |
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Definition
| decreases sound reflection (hair catches air=reflextion) |
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Term
| When is a linear array probe used in US? Why? |
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Definition
transrectal US, tendons in horses
produces RECTANGULAR cross sectional image |
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