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Principles of Radiographic Exposure > X-Ray Interactions > Flashcards

X-Ray Interactions Flashcards

1
Q

When x-ray passes through matter, it undergoes a process called: ______: the ____ in the number of x-ray ____ in the ____ as it passes through ____

Loss of ____ in the ____ as it travels through the ___.

  • ____ body part will ____ more ____ than a ___ body part.
A

When x-ray passes through matter, it undergoes a process called: ATTENUATION: the REDUCTION in the number of x-ray PHOTONS in the BEAM as it passes through MATTER

Loss of ENERGY in the BEAM as it travels through the BODY.

  • THICKER body part will ATTENUATE more ENERGY than a THINNER body part.
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2
Q

Attenuation

_____ in the number of x-ray ____ in the ____

A

Attenuation

REDUCTION in the number of x-ray PHOTONS in the BEAM

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3
Q

Attenuation

___% of the x-ray ___are _____ for each __ of ____ traveled.

Ex) at surface = 350 mR

1CM = 175 mR

2CM = 87.5 mR

3CM = 43.75 mR

A

Attenuation

50% of the x-ray PHOTONS are ATTENUATED for each CM of THICKNESS traveled.

Ex) at surface = 350 mR

1CM = 175 mR

2CM = 87.5 mR

3CM = 43.75 mR

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4
Q

Remnant Radiation

Remnant radiation is radiation that __________ and interacts with the ______.

A

Remnant Radiation

Remnant radiation is radiation that LEAVES THE PATIENT’S BODY and interacts with the IMAGE RECEPTOR (IR).

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5
Q

Interaction Basics

x-rays can:

  • be transmitted ______ OR

interact with:

  • ____
  • ____
  • ____
A

Interaction Basics

x-rays can:

  • be transmitted WITHOUT INTERACTION OR

interact with:

  • NUCLEUS OF AN ATOM
  • ENTIRE ATOM
  • ORBITAL ELECTRON
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6
Q

Photon Energy Dependent Interactions

  • Low energy photons interact with ____
  • Moderate energy photons interact with ____
  • High energy photons interact with _____
A

Photon Energy Dependent Interactions

  • Low energy photons interact with WHOLE ATOM
  • Moderate energy photons interact with ORBITAL ELECTRONS
  • High energy photons interact with NUCLEUS
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7
Q

Atomic Structure

  • Nucleus
  • ____ electrons
  • electrons close to the nucleus are “____” (closer you get to the nucleus it protects itself)
  • electrons further away are “____” or “____” (easier to knock out)
A

Atomic Structure

  • Nucleus
  • ORBITAL electrons
  • electrons close to the nucleus are “BOUND” (closer you get to the nucleus it protects itself)
  • electrons further away are “LOOSE” or “FREE” (easier to knock out)
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8
Q

What are the 5 basic interactions between x-rays and matter?

A

What are the 5 basic interactions between x-rays and matter?

  1. Coherent Scattering
  2. Photoelectric (PE) Absorption
  3. Compton Scattering
  4. Pair Production
  5. Photodisintegration
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9
Q

What are the photon energy ranges?

A

What are the photon energy ranges?

LOW, MODERATE, HIGH

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10
Q

Match the 5 basic interactions between x-rays and matters to the photon energy range

A

Coherent Scattering ———– Low photon energy range

Phoelectric (PE) Absorption and Compton Scattering ———– Moderate photon energy range

Pair Production and Photodisintegration ———- High photon energy range

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11
Q

Coherent Scatter

  • _____ photons (___ beam) interacts with ______ or _____
  • No electrons are ______
  • Photon’s energy is given up by the ____ as a ____ of the same ____ in an ____ direction
A

Coherent Scatter

  • INCIDENT photons (PRIMARY beam) interacts with ENTIRE ATOMS or OUTER ELECTRONS
  • No electrons are EJECTED FROM THE SHELLS
  • Photon’s energy is given up by the ATOM as a PHOTON of the same ENERGY in an ALTERED direction
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12
Q

Coherent Scatter

____ stabilizes itself by ___ a photon equal in energy to ________, but in a ________

A

Coherent Scatter

ATOM stabilizes itself by RELEASING a photon equal in energy to INCIDENT PHOTON (Ei), but in a DIFFERENT DIRECTION

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13
Q

__________ is usually not a factor in diagnostic x-ray due to:

  • occurs only when ______ is lower than ___ kEv
  • _____ will ____ out this ____ energy ___ before reaching the patient
  • Coherent scatter _______ to forming the ________
A

COHERENT SCATTER is usually not a factor in diagnostic x-ray due to:

  • occurs only when INCIDENT PHOTON ENERGY is lower than 10 kEv
  • FILTRATION will FILTER out this LOW energy PHOTON before reaching the patient
  • Coherent scatter DOES NOT CONTRIBUTE to forming the RADIOGRAPHIC IMAGE
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14
Q

Photoelectric Absorption (doesn’t create scatter - absorbs)

  • ______ in primary beam interacts with _______
  • ____ is ejected from it’s _____ and is termed a _____
  • ________ is absorbed by the _____ (that’s what causes _____)
A

Photoelectric Absorption (doesn’t create scatter - absorbs)

  • INCIDENT PHOTON in primary beam interacts with INNER SHELL ELECTRON
  • ELECTRON is ejected from it’s ORBIT and is termed a PHOTOELECTRON
  • INCIDENT PHOTON ENERGY is absorbed by the ATOM (that’s what causes BIOLOGICAL EFFECTS)
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15
Q

Photoelectric Absorption

  • ​To stabilize ____, _____electron move to ____ the _____
  • _________ cascade
A

Photoelectric Absorption

  • ​To stabilize ATOM, OUTER SHELL electron move to FILL IN the VOID
  • CHARACTERISTIC cascade
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16
Q

Photoelectric Absorption Happens When:

  • Low ___ atoms experience photoelectric absorption interaction with _____
  • Higher ___ atoms experience photoelectric absorption interaction in ___________

Ex) bone vs soft tissue

A

Photoelectric Absorption Happens When:

  • Low Z# (ATOMIC NUMBER) atoms experience photoelectric absorption interaction with K-SHELL
  • Higher Z# (ATOMIC NUMBER) atoms experience photoelectric absorption interaction in K, L, OR M SHELL

Ex) bone vs soft tissue

17
Q

Compton Scatter (when x-ray very gray)

  • ________ interacts with outer-shell, ____-bound ______ (in patient’s body) and ____ it (termed _______ or _____)
  • _______ is ______ from its ____ path and continues with _______
A

Compton Scatter (when x-ray very gray)

  • INCIDENT PHOTON (Ei) interacts with outer-shell, LOOSELY-bound ELECTRON (in patient’s body) and EJECTS it (termed COMPTON ELECTRON or RECOIL ELECTRON)
  • INCIDENT PHOTON is DEFLECTED from its ORIGINAL path and continues with DECREASED ENERGY
18
Q

Compton Scatter (when x-ray very gray)

  • ________ travels until it fills a _____ in another _____ (can help stabilize another atom)
  • ________ continue to ____ until ____ by the ______ effect
A

Compton Scatter (when x-ray very gray)

  • RECOIL ELECTRON travels until it fills a VACANCY in another ATOM (can help stabilize another atom)
  • SCATTERED PHOTON continue to INTERACT until ABSORBED by the PHOTOELECTRICAL effect
19
Q

Compton Scatter (when x-ray very gray)

  • Source of ________ and radiation ____ (gray film)
  • Most _____ travels in _____ direction
  • ______ - ____ electron may direct _____ (comes right back at you from patient body)
A

Compton Scatter (when x-ray very gray)

  • Source of OCCUPATIONAL EXPOSURE and radiation FOG (gray film)
  • Most SCATTER travels in FORWARD direction
  • BACKSCATTER - RECOIL electron may direct BACKWARDS (comes right back at you from patient body)
20
Q

Pair Production - doesn’t usually happen in diagnostic

  • __________ must be ___ MeV or ____ (diagnostic does kVP - doesn’t usually meet this requirement)
  • ________ absorbed (collides and hits) by _____ (of atom - becomes unstable)
    *
A

Pair Production - doesn’t usually happen in diagnostic

  • INCIDENT PHOTON ENERGY must be 1.02 MeV or HIGHER (diagnostic does kVP - doesn’t usually meet this requirement)
  • PHOTON ENERGY absorbed (collides and hits) by NUCLEUS (of atom - becomes unstable)
21
Q

Pair Production

  • the ____ becomes ____
  • ____ releases a _____ and ____ to ____ itself
  • this process is called _____
A

Pair Production

  • the NUCLEUS becomes UNSTABLE
  • NUCLEUS releases a POSITRON and NEGATRON to STABILIZE itself
  • this process is called ANNALATION
22
Q

Pair Production

  • Does not occur in _______ of _____
  • More significant in _______
  • Not a significant interaction until ____________ are being used
A

Pair Production

  • Does not occur in DIAGNOSTIC RANGE of ENERGY
  • More significant in RADIATION THERAPY
  • Not a significant interaction until ENERGIES OF 10 MeV are being used
23
Q

Photodisintegration

  • ______ energy photon (__ - ___ MeV or ___)
  • absorption of _____ by ___
  • excited ____ releases _____
A

Photodisintegration

  • EXTREMELY HIGH energy photon (7 - 15 MeV or GREATER)
  • absorption of PHOTON by NUCLEUS
  • excited NUCLEUS releases ALPHA PARTICLES
24
Q

What 2 of the 5 interactions have a significant impact on x-ray images?

A

What 2 of the 5 interactions have a significant impact on x-ray images?

  1. PHOTOELECTRIC ABSORPTION
  2. COMPTON SCATTERING
25
Q

Effect on Technical Factor Selection

As kVp increases (primary beam wavelength gets shorter)

  • the number of _____ transmitted without______ ______
  • decrease probability of _______
  • increase ______ interactions

vice versa is true

A

Effect on Technical Factor Selection

As kVp increases (primary beam wavelength gets shorter)

  • the number of PHOTONS transmitted without INTERACTION INCREASES
  • decrease probability of PHOTOELECTRIC ABSORPTION
  • increase COMPTON interactions

vice versa is true

26
Q

If holding a patient during an x-ray, you’ll get radiation from _______ and patient will get radiation from _______

A

If holding a patient during an x-ray, you’ll get radiation from COMPTON RADIATION and patient will get radiation from PHOTOELECTRIC EXPOSURE

27
Q

Effect on Technical Factor Selection

  • ______ typically predominates within ______x-ray energy range due to ________
A

Effect on Technical Factor Selection

  • COMPTON SCATTER typically predominates within DIAGNOSTIC x-ray energy range due to HIGHER kVp RANGES
28
Q

Effect on Technical Factor Selection

_________ interactions predominate in two circumstances:

  1. _________ ranges (__-__ kEv produced by ___-___ kVp techniques)
  2. In elements with ________ (bone, solid organs)
  • introduction of ________ results in ___________ (where ever contrast is, it’s going to absorb the radiation)
A

Effect on Technical Factor Selection

PHOTOELECTRIC ABSORPTION interactions predominate in two circumstances:

  1. LOWER ENERGY ranges (25-45 kEv produced by 40-70 kVp techniques)
  2. In elements with HIGHER Z# (ATOMIC NUMBER) (bone, solid organs)
  • introduction of CONTRAST AGENTS results in INCREASE PHOTOELECTRIC ABSORPTION (where ever contrast is, it’s going to absorb the radiation)
29
Q

Effects of Technical Factor Selection

When photoelectric absorption predominates:

  • resulting image with have _________ (more ___ to ___)
  • low ___, high ___

Optimum kVp = selecting the kVp which will produce a ________ and save the patient from _______

A

Effects of Technical Factor Selection

When photoelectric absorption predominates:

  • resulting image with have SHORT SCALE CONTRAST (more BLACK to WHITE)
  • low kVp, high mAs

Optimum kVp = selecting the kVp which will produce a GOOD IMAGE QUALITY and save the patient from HIGH RADIATION DOSAGE

30
Q

Effects on Technical Factor Selection

When Compton interactions predominates:

  • resulting image will have _______ (more ___ tones)
  • high ____, low ___
A

Effects on Technical Factor Selection

When Compton interactions predominates:

  • resulting image will have LONG SCALE CONTRAST (more GRAY tones)
  • high kVp, low mAs
31
Q

Patient Radiation Dosage

As photoelectric absorption increases, so does _________ (long energy beam, longer wavelenghs)

A

Patient Radiation Dosage

As photoelectric absorption increases, so does PATIENT’S RADIATION DOSAGE (long energy beam, longer wavelenghs)

32
Q

Radiographer’s Occupational Dosage

As ______ increases, so does the RT radiation exposure

A

Radiographer’s Occupational Dosage

As COMPTON increases, so does the RT radiation exposure

33
Q

Classical Scattering

  • ___ energy
  • interacts with ____
  • ____ significance to ___ imaging (because we filter radiation before it hits patient)
A

Classical Scattering

  • LOW energy
  • interacts with WHOLE ATOM
  • LITTLE significance to DIAGNOSTIC imaging (because we filter radiation before it hits patient)
34
Q

Name 8 qualities of photoelectric absorption (MACKPHIM)

A
  • Moderage energy
  • Atom becomes unstable
  • Characteristic cascade
  • Knock out with inter shell electrons
  • Patient radiation dose is increased
  • Happens at lower kVp levels and high Z#
  • Increase differential absorption
  • More black and white images
35
Q

List 9 qualities of Compton scattering (BLMHIMDIE)

A
  • Backscatter radiation (radiation fog)
  • Less differential absorption
  • Moderate energy
  • Higher kVp ranges
  • Interacts with outer shell electrons
  • More gray tones on film
  • Decrease radiation dosage to patient
  • Increase RT radiation dosage (holding patients)
  • Ejected electron is called a recoil electron

Principles of Radiographic Exposure (18 decks)

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