Ch3 Flashcards
- Incoming x-ray
photon interacts with
a loosely bound outer
(or middle) electron of
an atom
• The incoming x-ray
photon surrenders a
portion of its energy,
ionizing the atom.
Comptom scatter
Incoming x-ray photon interacts with the electric field surrounding the
nucleus of an atom of irradiation tissue and disappears.
• The energy of the photon is absorbed and transformed into a
negatron and a positron
Pair Production
An interaction that
occurs at more than 10 MeV in
high-energy radiation therapy
treatment machines
Photodisintegration
Occurs at an energy level of at least 1.022 million electron volts (MeV).
• Beyond diagnostic energy range.
Pair Production
Incoming x-ray photons the interacts a loosely bound outer electron of an atom
- Incoming x-ray photon surrenders a portion of his energy ionizing the atom
Compton scatter
Structures are similar in Atomicnumber z number ) and mass Must be distinguished by the use of
Contrast media
Barium iodine Bright/white
Positive contrast medium
Air dark/black
Negative contrast medium
The greater the difference in the amount of Photoelectric absorption the greater the
Contrast
As the absorption increases so does the potential…
Biologic damages
Less attenuation equals
Darker image
Image must have a significant amount of_____ In density to be clearly visualize
Variations
Atomic number for compact bone
13.8
Atomic number for soft tissue
7.4
Less density tissue less attenuation
Dense tissue more attenuation
These factors are known as
Influence attenuation