Radiology Flashcards
Angiography
vessel imaging
Arteriography
artery imaging
Venography
vein imaging
What type of waves are most damaging
high freq
short wavelength
Describe X-ray tube function
Cathode is source of electrons
Bombard tungsten on anode
Bombarding e slowed in the target, yielding bremsstrahlung (breaking) radiation
Bombarding e may eject an inner shell within the target material (vacancy is filled by outer shell electrons within the target –> the discrete energy difference is emitted as characteristic radiation
Bremsstrahlung radiation
“breaking”
produced by the deceleration of a charged particle when deflected by another charged particle
Characteristic radiaiton
Discrete amount of predictable energy
When element is bombarded with e, the target e is ejected from the inner shell of the atom
Ways x-rays interact with matter
penetration
absorption
scatter
Film blackening
the more readily x-ray photons reach the film, the more the film is blackened (air)
X-ray black-white spectrum
gas, fat, water, soft tissue, bone, metal
Lucency
black
Opacity
white
Contrast
ability to differentiate tissue differences on a film
Contrast agents
Types?
substances administered to enhance the body’s inherent contrast differences
oral, PO
rectal, PR
Intravenous, IV
Intra-arterial, intral-articular, intra-thecal
Advantages and disadvantages of radiologic procedures
Advantages:
cost-effective
useful starting point
Disadvantages
exposure to ioninzing radiation
limited assessment of soft tissue detail
MRI
magnetic field
radiofrequency pulse
observe generated signal (as magnetization vector returns to equil)
Diff tissues generate diff signals
Advantages and disadvantages of MRI
Advantages soft tissue characterization multiplanar imaging non-invasive vascular imaging (don't have to inject contrast, but can) No ionizing radiation
Disadvantages
cost
cannot be used in pts with pacemakers, neurostimulators, and unapproved metallic devices
Nuclear medicine imaging
FUNCTIONAL
gamma cameras detect gamma radiation emanating from pt
emitted radiation produces light through the use of scintillation crystals
light is detected/localized, creating an image
administered radioactivity localizes to particular tissues, depending on the radiopharmaceutical
Bone imaging –> nuclear imaging depends on…
blood flow
osteoblastic activity
rate of bone turnover
effects of metabolic stress on bone
Advantages and disadvantages of nuclear medicine imaging
Advantages:
functional assessment
high sensitivity for detecting abnormalities
Disadvantages:
limited anatomical detal
lower specificity for delineating abnormalities (see extra activity, but don’t know what the activity is)
Exposure to ionizing radiation
Arthrography
joint imaging
