Photon Interactions Flashcards
Name the interaction in which the x-ray photon does not transfer energy, does not ionize atoms, and does not deliver a dose of radation to the patient
Coherent Scatter
It is more likely to have compton’s scatter or PE occurring?
Compton’s Scatter
Name the photon Interacting that interacts with the nucleus causing 2 different particles
Pair Production
Name the interaction that involves the incident photon being absorbed breifly and then released in a different direction, but with no loss of energy
Coherent Scatter
Process that prevents photons from reaching a pre-defined destination is known as what?
Attenuation
Different types of matter absorb x-rays differently. Some absorb more; some absore less. The term usewd to describe this is?
Differential absorption
What is not present when comparing the PE formula to the compton’s formula?
Atomic number of matter
With reference to the image, why is it necessary to have PE interactions?
PE gives contrast to the image
When the energy of the photon increases the overall net interaction apparent on an image is?
compton’s scatter
Name the photon interaction resulting from low kVp energies, is not useful in diagnostic imaging, but is useful in mammography.
Coherent Scatter
Name the photon interaction used for the industry proposes
photodisintegration
In the PE what happens to the energy of the incident photon?
part overcomes binding K shell energy and part goes to eject electrom
X-ray photons leave the tube may undego 3 types of interaction. Name them
Absorbed, scattered or transmitted
In compton’s scatter, the ejected outer shell electrom is know as?
Compton’s electron or secondary electron
What determines which of the 5 interactions will occure when the x-ray photon interacts with the patient’s atoms
energy of the photon
Does bone or soft tissue have a higher physical density?
Bone (2x density of soft tissue
The difference between the number of photons in the primary beam and the number of photons that attenuated is know as
Remnant Radiation
Name the interaction which results in complete absorption of the incident photon
Photoelectric Effect
On an image, absorbed photons appear as?
White or light areas
Does complete absorption result in harmful effect to patient?
Yes. Absorption of energy=ionization occurred=patient dose of radiation
In compton’s scatter, where does the energy of the incident photon go?
1) overcomming binding energy
2) Compton’s photon
3) Compton’s electron
What must the energy of the incident photon be so pair production occurs?
1.02 MeV or 1022 KeV
According to the formula, the probability of PE occurring increases when what increases?
Atomic number of matter & physical density
In pair production, does the resulting particles have the same energy and charge
same energy, but one is negative and one is positive charged
The final x-ray beam is made of of what?
Transmitted and scattered photons
Can a grid clean up 100% of unwanted scatter radiation before is reaches the image receptor?
No!
Which interaction is the most important for radiographic contrast?
Photoelectric Effect
This photon interaction involves the absorption of the incident photon by the nucleus resulting in the nuclear fragment or nucleon.
Photodisintergration
Radiation interacting with the atoms of the patient can lead to?
Disruption of chemical bonds; function of organism may be harmed
If kVP is increased by 15% and mAs is halved, is there a change in density?
No!
When the energy of the photon decreasesoccurs, what happens to the amount of compton’s scatter? What happens to PE?
Both Increases
During the PE, outer shell electrons fill the inner shells releasing the extra energy as what?
Characterstic photons
The international units used to describe radiation amounts are:
Coulombs per kilogram, gray and the sievert
In compton’s scatter, does the incident photon cease to exist?
No, now scattered photon with less energy and different angle.
Why does compton’s scatter use less energy than PE?
Less energy needed to overcome binding energy of outer shell electron
What interaction results when the incident photon strikes the inner shell electron and then ceases to exist
Photoelectric Effect
Does the probability of compton’s scatter occurring increase or decrease when photon energy increases
Decreases slightly
The effects of ionization of the human body depends on what?
Amount of energy deposited and probability that vital molecules are affected
What photon interaction does this formula depict? (z3/e3)rho
PE
Name the tradition units used to measure radiation
Roentgen, rad, and rem
What photon interaction takes place when a incident photon interacts with an outer shell electron
Compton’s Scatter
Pair production interaction is important in two areas or radiology. Name them
Radiation Therapy and Positron emission tomography (PET)
Does boen or soft tissue have a higher atomic number?
Bone (about 2 times)
Name the interaction in which a photo electron results when an inner shell electron is ejected out of it’s shell
PE
Name the photon interaction that occurs at energies about 10 MeV
Photodisintegration
According to the formula, the probability of PE occuring decreases drastically with an increae in?
photon energy
