Radiology Flashcards
(28 cards)
what kind of radiation do X-rays use?
atomic electrons
what kind of radiation do CT scans use?
X-rays - atomic electrons
what does ultrasound use?
sound waves
what does magnetic resonance use?
radiofrequency
where do gamma rays originate?
atomic nucleus
what does radiation interaction with matter depend on?
energy of radiation and the density and composition of the matter
what is projection imaging x-rays?
generate x-rays, they are transmitted back, and you use radio-opaque contrast media like barium to help visualize structures
what is fluoroscopy radiography?
real-time imaging X-ray - live feed
how does tissue density equate to X-ray film
the more dense the tissue (bone) the whiter the color
benefits and drawbacks of transmission x-ray?
benefits: low cost, low dose, low risk, high resolution
drawbacks: need multiple projections, limited number of views, can’t see behind stuff
what is computed tomography?
X-ray source rotates around patient - get hundreds of “films” that put together a 3D picture
helical/spiral
get one slice
what is multiple detector CT (MDCT)?
multiple slices are obtained from the CT
what is multiple source CT?
use two x-ray sources with different energy levels to allow simultaneous acquisition of two different images with different contrast
what are the benefits and drawbacks to CT?
fast scanning, can see behind structures
drawbacks: limited soft tissue contrast, higher patient dose
what is nuclear medicine emission?
molecular tracers tagged with radioactive atoms - actively take up the tracer and wait for uptake and non-specific clearance - capture emission with gamma camera
what is single photon emission computed tomography?
a single photon travels through the body and deposits in camera - YOU are radioactive, you see where the tracer/photon went
what are some common radioisotopes?
iodine-123, indium-111, thallium-201, technetium-99m
compare NM to CT?
NM is more sensitive, but has a lower resolution
what is PET imaging?
take up a positron emitter orally or IV, proton annihilates with electron to form 2 photons traveling in opposite directions - these photons interact in tissue, use a coincidence counter (intrinsically quantitative)
what is the most commonly used tracer for PET?
FDG (fluorodeoxyglucose)
what kind of tissue is MRI good for?
soft tissue
is MRI ionizing or non-ionizing radiation?
non-ionizing, uses radio frequency
how does ultrasound work?
transducer produces high frequency mechanical pressure waves coupled to surface using gel; reflected waves is detected by transducer
what is doppler ultrasound used for?
detecting blood flow
