Flashcards in Introduction to imaging Deck (12)
an electromagnetic packet of energy with a extremely short wavelength between 0.1 and 10 nanometres
principles of x-ray production and capture.
1. the anode (tungsten filament) is heated and undergoes thermionic emission, discharging electrons
2. electrons attracted to positively charged cathode.
3. they hit the tungsten and cause the emission of x-rays.
why different structures have different appearances in x-ray imaging
this due to different attenuation coefficients ( the ability of a substance to stop radiation).
the ability of a substance to absorb and scatter radiation.
Rotating x-ray tube that produces multiple beams on a single axis of rotation.
pros and cons of CT scans
-great for defining bony detail
-soft tissue more visible than in normal x-ray imaging.
- exposure to radiation
ultrasound machine transmits high-frequency sound pulse which are reflected back and picked up at a boundary between tissues.
Ultrasound pros and cons
-great for soft tissues
patient ingests barium solution or it is inserted into them. X-rays are then used to produce a sort of "X-ray film".
Barium study pros and cons
pros: real-time images that are live.
cons: bowel disturbance, colonic perforation at enema
iodinated contrast media
used to clearly show anatomical structures on x-rays. The elements in them have a high atomic number and so absorb more x-rays than the surrounding tissue.