A photon with just slightly more energy than the electron binding energies of the tissue through which it passes is most likely to undergo what type of interactions?
Photoelectric
100
How much thicker does the anatomical part need to be in order to absorb twice as much of the x-ray beam?
4cm
100
If barium causes just as many Compton scatter interactions as normal fluids in the stomach, why does it show up white?
It has an atomic number of 56, so it can absorb a large number of x-rays.
100
What interaction causes the most image fog?
Compton
100
What happens to the mAs when there is a 4cm DECREASE in thickness?
Half the mAs
200
Roughly how much of the radiation STRIKING THE IMAGE RECEPTOR is secondary radiation?
75%
200
A photon is completely absorbed by an inner-shell orbital electron in the patient, and the electron ejects from its orbit. Name this interaction.
Photoelectric effect
200
What is the end product of Compton interaction?
Compton electron, secondary electron, and Compton scatter photon.
200
In bone, which interaction is more prevalent at very low kVp levels?
Photoelectric effect
200
What happens to the mAs when for every 4cm increase in thickness?
Double the mAs.
300
Which two interactions within the patient result in scatter radiation? Which one has the greatest?
Compton & Thompson Compton has 99%
300
A photon with much more energy than the electron binding energies of the tissue through which it passes is most likely to undergo what type of interaction?
Compton
300
Name two interactions in the patient that ionize atoms
Photoelectric and Compton
300
How is the attenuation increased with tissue thickness?
Exponentially
300
Define tissue density
The physical density of a substance is the amount of physical mass that is concentrated in a given area.
400
Which interaction contributes most to image contrast?
Photoelectric
400
A photon w/ slightly more energy than the electron binding energies of the tissue through which it passes is most likely to undergo what type of interaction?
Photoelectric effect
400
Name two interactions in the patient that cause scatter radiation
Thompson and Compton
400
How is tissue thickness described in relation to attenuation?
As the tissue area becomes thicker, the amount of attenuation is greater.
400
What happens to attenuation when the tissue density is higher?
greater attenuation
500
In bone, which interaction is more prevalent at very low kVp levels?
Photoelectric
500
How do bone molecules differ from soft tissue?
Bone is more physically dense and the atomic number is a notable difference.
500
What interaction contributes the most to subject contrast?
Photoelectric effect
500
What is the average thickness of the abdomen?
22cm
500
What happens to attenuation when the tissue density is lower?