Physics U6 &HW
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
|
|
||||
|---|---|---|---|---|---|
| Which of the following is NOT one of the five basic x-ray interactions with matter? | bremsstrahlung
🗑
|
||||
| which of the following x-rays would be most likely to undergo classical scattering? | 5 keV
🗑
|
||||
| Which of the following interactions contributes to image noise? | Compton scattering
🗑
|
||||
| Which of the following occurs in a Compton interaction? | An atom is ionized
🗑
|
||||
| If Ei= incident x-ray energy, E(s)=scattered x-ray energy, E(b) =electron binding energy, and E(KE)= secondary electron kinetic energy, then which of the following is true? | E(i) = E(s)+ E(b)+ E(KE)
🗑
|
||||
| If Ei= incident x-ray energy, E(s)=scattered x-ray energy, E(b) =electron binding energy, and E(KE)= secondary electron kinetic energy, then which of the following is true? | E(s) = E(KE)+E(i)-E(b)
🗑
|
||||
| During Compton effect, most of the incident x-ray energy is given to which of the following? | Scattered x-ray
🗑
|
||||
| After Compton scattering, the scattered x-ray has? | longer wavelength
🗑
|
||||
| Compton interaction affects the image by increasing which of the following? | Noise(fog)
🗑
|
||||
| The probability that an x-ray will interact with an outer shell electron is influence principally by | The energy of the incident x-ray
🗑
|
||||
| The compton effect is | independent of Z
🗑
|
||||
| The Compton effect is the principle source of | image noise(fog)
🗑
|
||||
| If 45keV x-ray interacts with the K-shell electron in an atom of molybdenum(E(b)=20keV) and ejects it with 8keV energy what will be the enrgy of the scattered x-ray? | 17keV
🗑
|
||||
| The probability that an x-ray will undergo Compton interaction decreases with | increasing x-ray energy
🗑
|
||||
| The compton interaction involves so-called "unbound" electron because | they have very low binding energy
🗑
|
||||
| Which of the following is the x-ray interaction that does NOT cause ionization? | Classical Scattering
🗑
|
||||
| Compton-scattered x-rays have | lower energy than an incident x-ray
🗑
|
||||
| If Ei= incident x-ray energy, E(s)=scattered x-ray energy, E(b) =electron binding energy, and E(KE)= photoelectric kinetic energy, then which of the following is true? | E(i) =E(b)+ E(KE)
🗑
|
||||
| If Ei= incident x-ray energy, E(s)=scattered x-ray energy, E(b) =electron binding energy, and E(KE)= photoelectric kinetic energy, then which of the following is true? | E(KE)=E(i)-E(b)
🗑
|
||||
| The photoelectric effect is principally associated with which of the following | Absorption of an x-ray
🗑
|
||||
| A 50 keV x-ray has a 0.02 chance of photelectric interaction with muscle(Z=7.4). What is the chance of interacting with bone(Z=13.8)? | .021024576
🗑
|
||||
| Which of the following has the lowest effective atomic number? | fat
🗑
|
||||
| Photoelectric interaction with soft tissue is most likely with which of the following x-rays | 0.3keV
🗑
|
||||
| during photoelectric interaction | An electron is emitted from the atom
🗑
|
||||
| During operation at 80 kVp, which of the following photoelectric interactions is most probable? | 30keV x-ray and bone
🗑
|
||||
| The radiographic image is formed principally by which of the following | photoelectric interaction
🗑
|
||||
| the probability of photoelectric effect varies as the function of x-ray energy(E)? | E(-3)
🗑
|
||||
| As a result of photoelectric interaction | an electron leaves the atom
🗑
|
||||
| the photoelectric effect is | The complete absorption of an x-ray with the subsequent emission of an electron
🗑
|
||||
| Lead has a K-shell electron binding energy of 88keV therefore an | 84 keV x-ray can undergo photoelectric interaction with the L-shell electron
🗑
|
||||
| A 39keV x-ray interacts through photoelectric effect with a k-shell electron of barium(binding energy 37keV0 therefore | the photoelectron will have 2 keV energy
🗑
|
||||
| the probability of photoelectric effect varies as what function of target atomic number (Z)? | Z(3)
🗑
|
||||
| Anatomic structures that readily transmit rays are called | radiolucent
🗑
|
||||
| differential absorption, although a complicated process, is basically the result of differences between | photoelectric effect and transmission
🗑
|
||||
| when a radiograph is taken | low kVp is necessary when soft tissue is imaged because it leads to high photoelectric effect
🗑
|
||||
| At what approximate x-ray energy is the probavility of a photoelectric interaction in soft tissue equal to the probability of compton interaction | 20keV
🗑
|
||||
| which of the following has the greatest mass density | bone
🗑
|
||||
| The colon is imaged during a barium enema examination principally because of differences in | subject atomic number
🗑
|
||||
| Air-contrast studies such as a colon examination are successful principally for which of the following reasons | there are differences in effective atomic number && in mass density
🗑
|
||||
| To optimize x-ray mammography | the main x-ray interaction should be the photoelectric effect
🗑
|
||||
| Differential absorption between bone and soft tissue occurs principally for which of the following reasons | There is a difference in effective atomic number
🗑
|
||||
| Angiography with iodinated compounds | works principally because of the differences in effective atomic number
🗑
|
||||
| Differential absorption is | The difference between those x-rays that are absorbed and those that are transmitted
🗑
|
||||
| As kVp increases the relative number of x-rays | that interact with tissue decreases
🗑
|
||||
| In which of the following tissue does differential absorption most depend on differences in mass density | lung and bone
🗑
|
||||
| How is photoelectric interaction with tissue related to the mass density(p) of the tissue | it is proportional
🗑
|
||||
| Lungs are imaged on a chest radiograph principally because of the differences in which of the following | tissue mass density
🗑
|
||||
| Differential absorption between lung and soft tissue occurs principally because of which of the following | the difference in mass density
🗑
|
||||
| The reduction in intensity of an x-ray beam after it passes through tissue is called | attenuation
🗑
|
||||
| x-ray transmission decreases exponentially, which also means that | the number of x-rays is never reduced to zero
🗑
|
||||
| Which process contributes most to the radiographic image | photoelectric effect
🗑
|
||||
| High kVp in chest radiograph will | reduce patient dose
🗑
|
||||
| Increasing kVp in imaging will | reduce skin dose
🗑
|
||||
| In high kVp chest radiography contrast depends most upon | Mass density
🗑
|
||||
| Microcalcifications are imaged on mammograms principally because of | Atomic number
🗑
|
||||
| More contrast is present froma barium examination than from an iodine examination because | barium has a higher atomic number
🗑
|
||||
| Photoelectric effect is proprtional to | Z(3)
🗑
|
||||
| what will increase the energy of bremsstrahlung radiation | x-ray tube voltage
🗑
|
||||
| Compton interaction occur with outer shell electrons and result in | recoil electron + photon of lower energy && reduced gray scale
🗑
|
||||
| At 60keV in soft tissue what predominates | compton scattering
🗑
|
||||
| What does the interaction of the photons with matter depend on? | the energy(kVp)& nature of the radiation photon; the atomic number(Z) of the subastance being irradiated
🗑
|
||||
| What is the difference between x-ray and gamma radiation; what are they identical in? | their origin is different x-ray comes from the shells and gamma comes from the nucleus; Their therapeutic effects are identical
🗑
|
||||
| High energy photons liberate ____ ____ from the orbits of atoms by various types of interactions | secondary electrons
🗑
|
||||
| What is ultimately responsible for the biologic effects of x-ray and gamma radiation | the energy absorbed from the liberation of the secondary electrons and their spatial distribution
🗑
|
||||
| What is the name of the differnt types of electrons ejected from the energy shells of an atom by incident photons called | secondary electrons
🗑
|
||||
| Name two different types of secondary electrons | recoil electrons and photoelectrons
🗑
|
||||
| Only what contributes to biologic effects | absorbed energy
🗑
|
||||
| What are the 4 types of diagnostically significant interactions | transmission of photons unchanged; unmodified scattering; photoelectric effect with true absorption ; modified scatter
🗑
|
||||
| what are the 2 types of therapeutic radiology | pair production and photodiscentigration
🗑
|
||||
| What interaction cause the blackness(density) on the film | transmission of photons unchanged
🗑
|
||||
| what are the two key factors that the interactions depend on? | kVp and atomic number
🗑
|
||||
| Atoms consist largely of what in the transmission of photons unchanged interaction | empty space
🗑
|
||||
| The actual particles in the atom(protons, neutrons, and electrons) constitute about how much of the volume of the atom | 10(-12) or one-million-millionth
🗑
|
||||
| A number of photons in any given x-ray beam passes directly through the atom without encountering an electron is called what type of interaction | transmission of Photons unchanged
🗑
|
||||
| The bringing about of less orderly arrangement of photon's direction due to the deflection caused by charged particles(orbital electrons) interposed in the path of the beam is known as | Scattering
🗑
|
||||
| Charged particles is also called | Orbital electrons
🗑
|
||||
| What is another name for unmodified scattering? | classical or Thompson scattering
🗑
|
||||
| What are the two types of scattering | modified and unmodified
🗑
|
||||
| Unmodified scattering refers to the scattering of radiation by what | relatively free charged particles(electrons) or outer shell electrons of an atom
🗑
|
||||
| Eplain classical scattering(unmodified)(where do electromagnetic waves pass;what does the electrical field of radiation do; what happens to the photon; what happens to the electron; what stays the same in the photon and what changes) | near an electron;sets the electron oscillating w/the same freq. of the incident electromagnetic waves;disappears in the electron;the electron then forces the radiation out & stops ocillating; photon is traveling in a differ direct but has the same energy
🗑
|
||||
| What is the new photon or scattered photon called and why | "in step" b/c this type of scattering of primary/incident photon is caherent or equal to the orginal energy
🗑
|
||||
| There is NO______ of energy from photo to electron in unmodified scattering. The ONLY thing that has changed is what? | transfer; the direction of the Incident photon)(now called scattered)
🗑
|
||||
| When does classical scatter occur | only if the incident photon does not have sufficient energy to dislodge the orbital electron; its predominant below energies of 10 keV
🗑
|
||||
| Does unmodified scattering have practical use in the Diagnostic Radiology | NO
🗑
|
||||
| Photoelectric interaction with true absorption creates | secondary radiation
🗑
|
||||
| Where does photoelectric absorption take place aand how much energy does it have | takes place when an incident photon(the primary beam) interacts with an inner atomic electron and has enough energy to eject the electron from its shell
🗑
|
||||
| All the energy of the photon during photoelectric interaction with true absorption must be what | equal or exceed the binding energy of the electron
🗑
|
||||
| During photoelectric interaction with true absorption the photons energy will be transferred where | to the dislodged electron
🗑
|
||||
| The nam given to the ejected orbital electron | photoelectron
🗑
|
||||
| what is the process called when the electron is given kinetic energy | photoelectric process
🗑
|
||||
| What interaction gives the white or clear image on a film | photoelectric interaction with true absorption
🗑
|
||||
| What is the formula for the Photoelectric Interaction with True Absorption? | E(i)= E(b) + E(ke)
🗑
|
||||
| During the Photoelectric Interaction, the secondary radiation occurs when the atom _______ the now vacant hole left by the dislodged __________. | Fill; Electron
🗑
|
||||
| When is the secondary radiation created and what is it characteristic of? | Radiation is created when the hole is filled and is characteristic of the shell that is now filled
🗑
|
||||
| What is the energy of the secondary radiation? | The inner-shell (K) binding energy - the binding energy of the shell the electron was pulled from (usually L)
🗑
|
||||
| During the Photoelectric Interaction with True Absorption, what type of energy is the secondary radiation? | Weak and not of diagnostic importance
🗑
|
||||
| The probability of occurrence for Photoelectric Interaction with True Absorption is dependent upon what 2 things? | 1)The kVp of the incident photon 2)The atomic number of the irradiated substance
🗑
|
||||
| The probability of occurrence for Photoelectric Interaction is ______________ proportional to the _______ of kVp. | Inversely Proportional; Cube of kVp (1/kVpᶾ)
(photon energy)
🗑
|
||||
| The probability of occurrence for the Photoelectric Interaction is __________ proportional to the ________ of the atomic number of the irradiated substance. | Directly Proportional; Cube of Z (Zᶾ)
(Atomic #)
🗑
|
||||
| As probability increases kVp__, wavelength___, Fequency____, Hardness of the beam___, and quality of the beam___ | decreases;increases;decreases;decreases;decreases
🗑
|
||||
| As the Atomic # of the irradiated substance increases the probability of occurrence for the Photoelectric Interaction ___________. | Increases
🗑
|
||||
| If you know the energy of the incident photon and the atomic number of the irradiated substance, what is the formula for the probability of occurrence? | Probability = Zᶾ/kVpᶾ
🗑
|
||||
| What is the energy of the photon for the Photoelectric Interaction w/ True Absorption? | Up to 50 kVp numbers
🗑
|
||||
| Photoelectric Interaction w/ True Absorption usually occurs with atoms of ________ atomic numbers. | High
🗑
|
||||
| During Photoelectric Interaction w/ True Absorption, why is it possible to see contrast differences in substances that have close atomic numbers? | The Density of the substances
🗑
|
||||
| The greater the density of a substance being irradiated means the ___________ the probability of Photoelectric Interaction. | Greater
🗑
|
||||
| Modified scattering is also referred to as the ___________ __________. | Compton Effect
🗑
|
||||
| During Modified scattering, what kind of electron does the incident photon interact with? | Loosely bound outer-shell electron
🗑
|
||||
| The Compton Effect occurs at photon energies up to _______ kVp. | 100 kVp
🗑
|
||||
| During the Compton Effect, the electron that interacts with the photon becomes a __________ or (AKA) ___________ electron. | Recoil or (AKA) Compton Electron
🗑
|
||||
| The amount of energy gained by the recoil electron depends on the __________ it's hit by the incident photon | Angle
🗑
|
||||
| During the Compton Effect, what becomes of the energy from the incident photon? | Some is used dislodging the electron and the remainder is divided between the recoil
🗑
|
||||
| During the Compton Effect (Modified Scattering) the more direct the hit of the incident photon to dislodge the electron, the __________ energy will be transferred to the ___________ Electron. | More; Recoil
🗑
|
||||
| During Modified Scattering, the less direct the hit of the photon on the electron, the _________ energy will remain with the _________ photon. | Less; Scattered
🗑
|
||||
| During the Compton Effect, how is the scattered photon different from the incident photon? | Traveling in a different direction; Energy (frequency) is decreased and wavelength
🗑
|
||||
| Give the formula for the transfer of energy from the incident photon during the Compton Effect: | E(i)= E(s) + E(b) + E(ke)
🗑
|
||||
| Give the subscripts for the Compton Effect formula: 1)i, 2)s, 3)b, 4)ke | 1)i=Incident photon 2)s=Scattered photon 3)b=Binding energy of electron 4)ke=Kinetic
🗑
|
||||
| This is radiation that is scattered 180° from the direction of travel of the incident photon: | Backscatter Radiation
🗑
|
||||
| Backscatter radiation is also known as ________ and puts the _________ on the radiographic image. | fog; gray
🗑
|
||||
| 1)Photoelectric Interaction: Photon energy: 2)Compton Scattering: Photon energy: 3)Thompson Scattering: Photon energy: | 1)Up to 50 kVp 2)Up to 100 kVp 3)Below 10 keV
🗑
|
||||
| What interactions occur with INNERSHELL electrons? | Photoelectric Interactions w/ True Absorption
🗑
|
||||
| What interactions occur with OUTERSHELL electrons? | Unmodified Classical (Thompson) Scattering & Modified Scattering/Compton Effect
🗑
|
||||
| Which interaction is responsible for Fog? | Modified Scattering / Compton Effect
🗑
|
||||
| What interaction does not involve an electron? | Transmission of Photons Unchanged
🗑
|
||||
| Which interactions eject orbital electrons? | Photoelectric and Compton
🗑
|
||||
| Which interaction can cause images of the cassette locks on the back of the cassette to show up on the Radiograph? | Backscatter from Modified Scattering
🗑
|
||||
| Which interaction increases the scale of contrast and actually "degrades" contrast? | Compton Scattering
🗑
|
||||
| What devices are available to reduce the negative effects of Compton Scattering? | Collimation and Grids
🗑
|
||||
| Increasing the hardness (quality) of the beam and Increasing kVp will have what effect on the probability of Compton Scattering? | Decrease the probability( also increase of frequency and wavelength)
🗑
|
||||
| Increasing the photon energy ____________ the probability of Compton Scattering and ____________ the problem caused by Compton Scattering. | Decreases; Increases
🗑
|
||||
| Why does the problem with Compton Scattering increase as the energy of the incident photon increases? | The scattered photons produced from the interaction will be strong enough to (1) continue traveling in a straight line to the film & (2) are stronger when they reach the film
🗑
|
||||
| Why does the probability of occurrence decrease as the kVp increases? | Because the number of interactions will decrease as the photon's energy increases (it will not interact with an electron and go straight through the patient to the film)
🗑
|
||||
| What are some cassettes designed with to prevent backscatter | lead lined backs because it can cause images of back locks of the cassette to show up on the film if not
🗑
|
||||
| Pair Production occurs with photon energies of: | At least 1.02 MeV
🗑
|
||||
| What subatomic particle does the photon interact with during Pair Production Interaction? | The Nucleus
🗑
|
||||
| During Pair Production, a photon disappears into a ___________ of an atom and ejects 1 _____________ electron and 1 ____________ electron. | Nucleus; Negative; Positive
🗑
|
||||
| What is the name of and what becomes of the ejected negative electron during Pair Production? | Negatron; Behaves like any other electron
🗑
|
||||
| What becomes of the ejected Positron during Pair Production? | Slows by interacting with other atoms and combines with an electron
🗑
|
||||
| Why would a Positron combine with an electron from another atom? | Because it's charge is positive and will combine with subatomic negative particles (electrons)
🗑
|
||||
| After a Positron combines with an electron it forms a ___________. | Positronium
🗑
|
||||
| A Positronium is an _________ atom which is very ___________. The subatomic particles that created to form a Positronium _____________ eachother. | Exotic Atom; Very Unstable; Annihilate
🗑
|
||||
| When the Positronium explodes it creates _______ Photons of ___________ energies | 2; equal
🗑
|
||||
| If the incident photon was 1.02 MeV, what would be the energy of the resulting gamma photons be and how will they travel? | 0.51 MeV Each; Travel in opposite directions
🗑
|
||||
| During Pair Production the first conversion is from energy to ______. The Second conversion is from ____________ to __________. | Matter (photon to positronium); Matter to energy (positronium to 2 photons)
🗑
|
||||
| The reaction that causes the Positronium to produce 2 photons is called the _____________ Reaction. | Annihilation
🗑
|
||||
| Pair Production occurs with photon energies from _________ to __________. | 1.02 MeV to 10 MeV
🗑
|
||||
| What is differential absorption? | the difference b/t those x-rays absorbed photoelectrically and those not absorbed; this is how an x-ray image is formed
🗑
|
||||
| Differential Absorption increases as kVp is | decreased
🗑
|
||||
| Absorbed radiation and appears clear | radiopaque
🗑
|
||||
| Allows radiation to pass through and appears black | radiolucent
🗑
|
||||
| The interaction b/t x-rays and tissue is proportional to the mass density of the tissue | mass density
🗑
|
||||
| if mass density is doubled then what happens to the photoelectric interaction | it is doubled
🗑
|
||||
| Radiation that is absorbed by a given percent per each incremental thickness of matter | exponential attenuation
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
atesta0824
Popular Physics sets