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Physics > X-Ray and Gamma Ray Interactions Ch. 5 & 7 > Flashcards

X-Ray and Gamma Ray Interactions Ch. 5 & 7 Flashcards

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1
Q

Monoenergetic photon beams interacting with tissue are attenuated:

A. Linearly
B. Exponentially
C. Proportional to the density of tissue
D. None of the above

A

B. Exponentially

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2
Q

Most often when a photon undergoes scattering:

A. It gains energy
B. Its energy remains unchanged
C. Its energy decreases
D. None of the above

A

C. Its energy decreases

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3
Q

Which coefficient is used to calculate energy absorbed:

A. Attenuation
B. Transfer
C. Absorption
D. Scatter

A

C. Absorption

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4
Q

The annihilation radiation produces:

A. 2 electrons
B. 1 electron and 1 positron
C. 2 photons and energy of 0.511 MeV each
D. 1 photon of 1.02 MeV

A

C. 2 photons and energy of 0.511 MeV each

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5
Q

A half value layer of a photon beam is:

A. The thickness required to reduce the beam to half of its initial intensity
B. Half of the number of photons in the beam
C. The photon beam is blocked into half
D. None of the above

A

A. The thickness required to reduce the beam to half of its initial intensity

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6
Q

X-rays and gamma rays in their interaction with tissue

A. Produce high speed electrons
B. Deposit energy
C. Undergo scattering
D. Produce ionization
E. All of the above

A

E. All of the above

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7
Q

Photons transfer their energy directly to tissue by:

A. Scatter
B. The production of Cerenkov radiation
C. Absorption
D. Attenuation
E. Production of bremsstrahlung

A

C. Absorption

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8
Q

The major type of interaction in megavoltage photon therapy is:

A. Photoelectric
B. Compton
C. Pair production
D. Triplet production

A

B. Compton

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9
Q

The photoelectric process of interaction is between the photons and:

A. The nucleus of the atom
B. The orbital electrons
C. Either of the above
D. None of the above

A

B. The orbital electrons

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10
Q

What is the threshold energy for pair production:

A. 0.511 MeV
B. 1.02 MeV
C. 1.533 MeV
D. 981 MeV

A

B. 1.02 MeV

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11
Q

The probability that a photon interacts with a material is:

A. Dependent on its density
B. Proportional to the total attenuation coeffeicient
C. Inversely proportional to the number of protons in the atom
D. All of the above

A

B. Proportional to the total attenuation coeffeicient

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12
Q

Which of the following materials will be most effective in attenuating a high energy
photon beam:

A. Air
B. Water
C. Lead
D. Copper

A

C. Lead

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13
Q

Pair production becomes significant (i.e., not accounted for in routine calculations)
in tissue above:

A. 5 MeV
B. 10 MeV
C. 15 MeV
D. 20 MeV

A

B. 10 MeV

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14
Q

The mass attenuation for photons in soft tissue:

A. Is maximum at 25 MeV
B. Increases continuously with energy
C. Decreases continuously with energy
D. Decreases to about 3 MeV, then increases

A

C. Decreases continuously with energy

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15
Q

Charged particles interact with body tissues by:

A. Photoelectric process
B. Triplet production
C. Ionization and excitation
D. All of the above

A

C. Ionization and excitation

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16
Q

X-rays are more likely to be produced by interaction between:

A. Alpha particles and nuclei
B. Protons and nuclei
C. Electrons and nuclei
D. Neutrons and nuclei

A

C. Electrons and nuclei

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17
Q

The rate of kinetic energy loss per unit path length by a charged particle is called:

A. Linear attenuation coefficient
B. Stopping power
C. Mass energy absorption coefficient
D. All of the above

A

B. Stopping power

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18
Q

The rate of energy loss by a charged particle is:

A. Proportional to the particle charge
B. Proportional to the square of the particle charge
C. Independent of the charge
D. None of the above

A

B. Proportional to the square of the particle charge

19
Q

Heavy particles lose most of their energy:

A. Immediately as they enter the medium
B. In the middle of their range
C. Near the end of their range
D. Equally throughout their range

A

C. Near the end of their range

20
Q

The Bragg peak is not observed in electrons because of their:

A. High speed
B. Negative charge
C. Small mass
D. Short life span

A

C. Small mass

21
Q

Excitation produced by electron beams is of:

A. Nucleus of the atom
B. Neutrons of the atom
C. Orbital electrons of the atom
D. Protons of the atom

A

C. Orbital electrons of the atom

22
Q

Which of the following particles will penetrate the deepest in tissue:

A. 20 keV Auger electron
B. 10 MeV alpha particle
C. 20 keV proton
D. 1 MeV positron
E. 2 MeV beta particle

A

E. 2 MeV beta particle

23
Q

When an electron is ejected from an atom and leaves an ionization track it is called:

A. A characteristic electron
B. An Auger electron
C. A delta ray
D. An electrostatic charge

A

C. A delta ray

24
Q

In the production of bremsstrahlung, the electron:

A. Ejects a cloud of electrons
B. Slows down and loses some of its energy as an x-ray photon
C. Produces a heavy particle
D. Ejects an electron from the atom

A

B. Slows down and loses some of its energy as an x-ray photon

25
Q

Neutrons are:

A. Directly ionizing particles
B. Indirectly ionizing particles
C. Electromagnetic radiation
D. Radiofrequency radiation

A

B. Indirectly ionizing particles

26
Q

Most neutron interactions in soft tissue produce:

A. Recoil protons
B. High energy electrons
C. Visible light
D. Auger electrons

A

A. Recoil protons

27
Q

The most efficient absorber of neutrons is:

A. Copper
B. Aluminum
C. Borated polyethylene
D. Lead

A

C. Borated polyethylene

28
Q

When exposed to the same neutron beam, which of the following tissues receives a
higher absorbed dose:

A. Muscle
B. Lung
C. Fat
D. Brain

A

C. Fat

29
Q

Neutron dose estimates have a higher uncertainty because they:

A. Are difficult to detect
B. Lose significant energy in air
C. Do not produce ionization
D. Produce diverse secondary radiation

A

D. Produce diverse secondary radiation

30
Q

In order for a photon to ionize an atom, its energy must be:
a. greater than the binding energy of an electron in the atom
b. less than the binding energy of an electron in the atom
c. equal to the binding energy of an electron in the atom
d. none of the above

A

a. greater than the binding energy of an electron in the atom

31
Q

Ionization implies the removal of an electron from the atom.
True
False

A

True

32
Q

In coherent scattering, the energy of the photon is:
a. increased
b. decreased
c. unchanged
d. none of the above

A

c. unchanged

33
Q

The major type of interaction in megavoltage photon therapy is:
a. photoelectric
b. compton
c. pair production
d. triplet production

A

b. compton

34
Q

The only interaction in which the likelihood increases with an increase in photon energy:
a. Compton
b. Pair Production
c. Photoelectric
d. Coherent
e. None of the above

A

b. Pair Production

35
Q

The second HVL of a photon beam is the same as the first HVL:
a. for all x-ray tube generated photon beams
b. only if the energy is below 100 kVp
c. only if the beam is monoenergetic (e.g. gamma rays)
d. never; it is always less

A

c. only if the beam is monoenergetic (e.g. gamma rays)

36
Q

The amount of attenuation of a photon beam by a material depends upon:

a. energy of photon
b. linear attenuation coefficient of the material
c. thickness of the material
d. all of the above

A

d. all of the above

37
Q

Ionization implies:
A. an excited state of the atom
B. the production of x-rays
C. the removal of an electron from the atom
D. a neutral state of the atom

A

C. the removal of an electron from the atom

38
Q

The amount of attenuation of a photon beam by a material depends upon:
A. energy of the photon
B. linear attenuation coefficient of the material
C. thickness of the material
D. all of the above

A

D. all of the above

39
Q

In coherent scattering the energy of the photon is:
A. increased
B. decreased
C. unchanged
D. none of the above

A

C. unchanged

40
Q

The photoelectric process is most significant in the energy range of:
A. 1 keV to 100 keV
B. 100 keV to 500 keV
C. 500 keV to 1 MeV
D. 1 MeV to 5 MeV

A

A. 1 keV to 100 keV

41
Q

When a photon undergoes a Compton process:
A. a photon of reduced energy is scattered
B. it is completely absorbed
C. characteristic x-rays are produced
D. two Compton electrons are produced

A

A. a photon of reduced energy is scattered

42
Q

The linear attenuation coefficient (μ) for monoenergetic photons is equal to:
A. HVL x 1.44
B. 0.693/HVL
C. HVL x 0.693
D. (HVL) to the power half

A

B. 0.693/HVL

43
Q

Pair Production refers to:
A. two orbital electrons are ejected from the atom
B. one electron and one positron is ejected from the atom
C. in the field of the nucleus, the energy of the interacting photon is
converted into a positron and an electron
D. any of the above

A

C. in the field of the nucleus, the energy of the interacting photon is
converted into a positron and an electron

Physics (11 decks)

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