Ch. 12 X-Ray Interactions Flashcards
When an x-ray photon passes through matter, it undergoes a process called:
Attenuation
During the process of attenuation, x-ray photons in the beam:
- Reduce in number
- Lose energy
- Interact
During the process of attenuation, the x-ray photon may interact with:
- The nucleus
- The entire atom
- An orbital electron
Which atomic shell possesses the highest binding energy?
The K shell.
In which element are the inner-shell electrons more tightly bound to the nucleus?
a. Mercury (Z#=80)
b. Tungsten (Z#=74)
c. Lead (Z#=82)
d. Chromium (Z#=24)
c. Lead (Z#=82)
- highest atomic number out of the choices
Which energy-level electrons possess the highest total energy?
a. K
b. L
c. M
d. N
d. N
As the electron shells move farther from the nucleus, total electron energies ____ and binding energies ____.
Increase; decrease
When x-ray interacts with matter and scatters, the photon:
Exits with less energy
When x-ray photons interact with matter and change direction, the process is called:
Scatter
When an x-ray photon with a slightly greater energy than the biding energy of the inner-shell electron interacts with that inner-shell electron, the following interaction results:
Photoelectric absorption
During photoelectric absorption, a/an ____ shell electron is ejected.
Inner
During photoelectric absorption, the ejected electron is called:
A photoelectron
A photoelectron:
- Is matter and possesses energy
- Typically travels 1-2 mm in soft tissue
- Capable of creating biological changes
When an electron from an outer shell fills a vacancy in an inner shell,
A photon is released.
During the photoelectric interaction, as an electron transfers from an outer shell to a vacant inner shell, energy is released in the form of:
A characteristic photon
Secondary radiation energies are highest for which element?
a. Hydrogen
b. Carbon
c. Barium
d. Oxygen
c. Barium
An interaction that occurs between very low energy x-ray photons and matter is called _____ scatter.
- Coherent
- Classical
- Unmodified
During coherent scattering, the scattered photon possesses ______ as the incident photon.
The same energy, the same frequency, and the same wavelength
Compton scattering occurs when an incident x-ray photon interacts with a ____ electron.
Loosely bound outer-shell
The electron dislodged during Compton scattering is called the:
Recoil electron
The photon that exits the atom after a Compton scattering is called the ______.
Compton scattered electron.
During Compton scattering, the incident photon energy is divided between the:
Recoil electron and the scattered photon
As the angle of deflection is increased from 0 degrees to 180 degrees:
Greater energy is imparted to the recoil electron
Unwanted radiographic image densities caused predominantly by scattered photons is called:
Radiation fog
During which interaction with matter is the x-ray photon converted to matter in the form of two electrons?
Pair production
In which process is matter converted back to energy?
Annihilation reaction
What interactions has a significant impact on the x-ray image?
Photoelectric absorption and Compton scattering
In the human body, ____ is the predominant interaction through most of the diagnostic x-ray range.
Compton scattering
What interaction with matter results in a radiograph with a loss of radiographic image contrast?
Compton scattering
Which interaction with matter results in an image with higher contrast?
Photoelectric interaction
In an effort to decrease the mAs of an exposure, the 15% rule of kVp change may be considered. Changing the original kVp of 84 using the 15% rule will have what impact?
Greater Compton scatter interactions
The incidence of the photoelectric effect increases with:
Increasing atomic number of the absorber
In diagnostic radiology, radiographic image contrast is principally due to the predominance of:
Photoelectric interactions
An incident photon with 35 keV is most likely to interact with the K-shell electron of what atom?
Iodine
