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7 Cards in this Set
- Front
- Back
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Radiograph
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X-ray (fancy, no?)
X-ray travels through and is attenuated by body, strikes radiographic cassette which fluoresces, exposing film placed next to the cassette (this is how x-rays worked 1000 years ago and it is unclear why it is in a modern medical school syllabus ... but i digress) air/fat - black water - gray bone - white |
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Computed Radiography
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X-ray, but film replaced by phosphor plate. laser beam scans the plate, releasing light which is then converted by a "computer" to a digital image. "which can be viewed on a monitor or transferred via networks" (data is transferred "via networks" through long metal wires which connect magnets on either end. when one magnet moves, the magnetic field is propagated down the wire and manifests as a force expressed on the other magnet. hence an electronic signal). this process summed billions of times allows two "computers" to communicate
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PACS
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Picture Archiving and Communication System (aka any computer less than 20 years old)
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Ultrasound
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Images created by a transducer emitting high frequency sound waves into the body and measuring the reflected waves off of tissue of various densities
pros: -non-invasive w/out radiation -inexpensive, portable -multiplanar imaging -3D, 4D, & doppler modes cons: -small field of view -can't see through bone or lots of fat -operator skill dependent |
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Computed Tomography
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Many X-rays taken from all angles around the body and used to build 1-10mm sliced views of a pt.
Some fat provides contrast around organs Contrast media can be given to enhance imaging of bowel loops pros: -large field of view -high resolution -less operator dependency -fast cons: -high doses of radiation -poor soft tissue differentiation -rxn to contrast media |
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PET-CT
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combining CT technology with Positron Emission Tomography (PET) imaging, in which the pt consumes radiolabeled glucose which "lights up" highly metabolic (malignant) cells
cons: -high radiation exposure -$$$ -expertise to differentiated pathologic from normal highly metabolic tissue (myocardium, kidneys, bladder, active bowel, active muscles, etc) |
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MRI
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Magnetic Resonance Imaging
The pt is placed in a large magnetic field. Following application of an RF frequency signal, aligned spins of the pt's atoms are perturbed and return to their natural state releasing a characteristic electromagnetic pulse which is detected by the MRI and can correspond to different physical properties of the tissue. Images in any plane can be obtained and can be enhanced by Gadolinium pros: -large field of view -good resolution w/out radiation -not operator dependent -best soft tissue contrast cons: -motion artifacts -$$$ -time -gadolinium + kidneys = bad -small space in scanner (bad for claustrophobes and fatties) -requires detailed knowledge of related physics (i think this is a pro) -NO METAL |
