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16 Cards in this Set
- Front
- Back
What type of imaging uses ionizing radiation?
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-plain film or conventional x-rays
-mammography -fluoroscopy -CT = computed tomography -nuclear medicine |
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What are the basic physical principles of nuclear medicine?
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Pt injected w/ or ingests radioactive substance (emits gamma rays) that is metabolized in certain parts of tissues so you can see what tissues are taking up this substance (function) by emitting ionizing radiation on the body to see images
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What are the basic physical principles of ultrasound?
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transmission of sound waves through the body and then it measures the reflected echo
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What are the basic physical principles of magnetic resonance imaging?
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MRI
PT is placed in magnetic field to influence H atoms in tissues, then the body is pulsed with radio waves and H atoms return to equilibrium |
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What are the basic physical principles of conventional radiography?
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ionizing radiation creates images to see the radiodensity (how thick an object is and proportional to atomic number) Certain structures observe more x-ray beams than others
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In conventional radiology, what color is:
1) air 2) soft tissue 3) bone 4) metals |
1) black
2) gray 3) white 4) white |
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What are the advantages and disadvantages of conventional radiography?
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advantages:
readily available cheap minimum radiation exposure non-invasive disadvantages: all superimposed images 2-D so you need 2 fields |
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What are the basic physical principles of fluoroscopy?
What are common routes of administration and contrast media used for certain studies? |
use a contrast study (to differentiate tissues of similar density by administer contrast media) then use a continuous beam of x-rays to pass through patient
gastrointestinal: by mouth or rectum (barium, water soluble contrast if you suspect leak) urinary tract: catheterization or vascular injection vascular system and joints: injection use water soluble contrast for urinary and vascular studies |
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What good imaging tools to view in real time?
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fluoroscopy
ultra sound |
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What is a voiding cystourethrogram?
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evaluation of the bladder after adding water soluble contrast via bladder catheter
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What are the advantages and disadvantages of CT?
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advantage:
cross sectional images eliminates the problem of superimposing images high sensitivity btw soft tissues of similar density (quantitatively measure x-ray absorption) fast 3D reconstruction disadvantage: high radiation dose exposure to intravascular contrast expensive |
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Define the hounsfield units to characterize anatomic tissues in CT.
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Air: (-1000 HU) black
Fat: (-100 HU) Water: (0HU) gray soft tissues: (+20-70 HU) bone: (+400 HU) white |
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What are the advantages and disadvantages of ultrasounds?
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advantages:
real-time no ionizing radiation good resolution portable cheap Disadvantages: technically difficult to use hard to see deep when have bone and gas limit field of view |
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What are the advantages and disadvantages of MRI?
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advantages:
better differentiation of soft tissues than CT 3D reformation contrast free vascular imaging Disadvantage: long acquisition time strong magnetic field interferes with pacemakers, and metallic foreign bodies can't bring ferromagnetic items into the MRI examination room |
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What 2 imaging techniques can you fuse to increase the diagnostic power?
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PET (nuclear medicine) and CT
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How much radiation do you get from an x ray compared to a PET/CT scan?
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Xray: <1 CXR (3 hrs of background)
PET/CT: 1165 CXR (12 yrs) |