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37 Cards in this Set
- Front
- Back
X-rays
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ionizing electromagnetic radiation produced by high-speed electrons colliding w/ a target media like Tungsten
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Fluoroscopy
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continuous or pulsed x-ray that can give you a view over time. good for watching movement of diaphragm, GI tract, vessels, heart, catheters. downside: radiation exposure
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Oral contrast
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used to see GI tract
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IV contrast
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shows vessels, renal collecting system or specific organs. Intravenous or intraarterial
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2 types of oral contrast
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Barium sulfate and water-soluble contrast
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Barium sulfate
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good density/coating
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Barium concerns
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Don't use if concerned about leak >> can cause granulomatous response in peritoneum. Turns to concrete if it sits in colon for too long.
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water-soluble contrast
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Less dense and doesn't coat as well as barium. hypertonic solution - don't use if aspiration is a concern b/c it will pull fluid into lung.
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iodine-based vascular contrast
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use for CT, IVP, angiogram
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galladinium-based vascular contrast
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use for MRI; toxic and paramagnetic
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Interventional radiology
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uses minimally invasive techniques to treat or evaluate lesion
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CT
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uses rotating x-ray source to construct multiplanar images of patient
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CT good for
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finding abnormal morphology, in vivo "autopsy"
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Ultrasound
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uses sound waves to generate image (returning waves)
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Doppler US
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allows you to determine direction and velocity of flow
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MRI
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uses magnetic properties of tissue; no radiation.
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T1 MRI
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water is black, fat/protein is white
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T2 MRI
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water is white, fat/protein is black
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MRI vs CT
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MRI has better contrast, can image in any plane desired
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Nuclear medicine
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radioisotope injected into pt, who becomes source of radiation. ex: PET scan w/ radioactive glucose, bone scan
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average background radiation exposure in NC
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3-4 mSV/year
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biggest source
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radon
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abdominal CT exposure
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5-7mSV
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coronary angiogram
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5-10mSV
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CXR
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.1-.2 mSV
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how does radiation harm you?
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acts directly or via produced free radicals to disrupt/alter molecular structures
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stochastic effects
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probabilistic effects; likelihood related to frequency of exposure. severity not related to dose. either it happens or it doesn't. ex: cancer
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non-stochastic effects
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dose threshold (doesn't occur below certain dose); severity of effect related to dose. ex: skin redness, infertility, cataracs.
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radiation during pregnancy
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increases risk of malformation/childhood cancer. depends on timing/dose
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<2weeks
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all or nothing response
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2-8wks
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organogenesis; >100mGy
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9-15 wks
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greater risk >150
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MRI contraindication
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pacemaker, cochlear implants, ferromagnetic aneurysm clips, iron particles in eye
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iodinated IV contrast adverse events
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allergies, contraste nephropathy, extravasation
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iodinated IV contrast allergies
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tough to predict but asthma/multiple allergies increases risk. Pretreat w/ steroids.
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contrast nephropathy
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increased risk if renal insufficiency, DB, dehydration, CHF
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Gd contrast reaction
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nephrogenic systemic fibrosis >> increased collagen deposition in skin/diaphragm/heart/lung in small # w/ impaired renal function
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