LRA-211 RADIOGRAPHIC IMAGE
PRODUCTION QUESTIONS AND
ANSWERS WITH COMPLETE
SOLUTIONS 100% CORRECT!!!
1. 4 things that make an x-ray:
Answer: ✔✔
1. Vacuum
2. Source of electrons
3. High potential difference
4. Deceleration of electrons
Explanation:
To produce x-rays, the following are necessary:
o Vacuum: A vacuum is required inside the x-ray tube to prevent the
electrons from interacting with gas molecules, which would interfere
with the efficient flow of electrons.
o Source of electrons: The filament in the cathode generates the
electrons by heating up, releasing electrons through thermionic
emission.
o High potential difference: A high voltage (kVp) is applied across the
tube, which accelerates the electrons toward the anode at high speed.
o Deceleration of electrons: When the accelerated electrons interact
with the target material (usually tungsten), they decelerate, losing
energy in the form of x-ray photons.
2. Bremsstrahlung Interaction:
Answer: ✔✔
An incident electron interacts with the force field of the nucleus, causing the
electron to slow down, diverting its course. The electron loses energy and
, changes direction. The energy lost is emitted as a bremsstrahlung photon,
and the photon energy is approximately half the difference between the
entering and exiting kinetic energy of the electron.
Explanation:
Bremsstrahlung (or "braking radiation") occurs when an incident electron
passes close to the nucleus of an atom and is slowed down by the
electrostatic force of the nucleus. This deceleration causes the electron to
lose energy, which is emitted as an x-ray photon. The energy of this photon
depends on how much the electron is slowed down. The more significant the
interaction with the nucleus, the higher the energy of the emitted photon.
3. Characteristic Interaction:
Answer: ✔✔
The incident electron interacts with an inner-shell electron, knocking it out
and continuing in a slightly different direction, creating a hole in the inner
shell, which makes the shell unstable.
Explanation:
In characteristic interactions, a high-speed electron from the cathode
strikes an inner-shell electron of the target material (typically tungsten),
ejecting it from the atom. This creates a vacancy in the inner shell (e.g., the
K-shell). An electron from a higher energy level then falls into the vacancy,
emitting an x-ray photon with energy equal to the difference in binding
energies between the shells. This process results in the emission of
characteristic x-rays specific to the target element.
4. Maximum allowed leakage from machine:
Answer: ✔✔ 100 mR per hour at 1 meter
Explanation:
The maximum allowable leakage radiation from an x-ray machine is
regulated to ensure the safety of radiographers and others near the
equipment. The maximum permitted leakage is 100 milliroentgens per
hour (mR/hr) measured at a distance of 1 meter from the tube housing.
PRODUCTION QUESTIONS AND
ANSWERS WITH COMPLETE
SOLUTIONS 100% CORRECT!!!
1. 4 things that make an x-ray:
Answer: ✔✔
1. Vacuum
2. Source of electrons
3. High potential difference
4. Deceleration of electrons
Explanation:
To produce x-rays, the following are necessary:
o Vacuum: A vacuum is required inside the x-ray tube to prevent the
electrons from interacting with gas molecules, which would interfere
with the efficient flow of electrons.
o Source of electrons: The filament in the cathode generates the
electrons by heating up, releasing electrons through thermionic
emission.
o High potential difference: A high voltage (kVp) is applied across the
tube, which accelerates the electrons toward the anode at high speed.
o Deceleration of electrons: When the accelerated electrons interact
with the target material (usually tungsten), they decelerate, losing
energy in the form of x-ray photons.
2. Bremsstrahlung Interaction:
Answer: ✔✔
An incident electron interacts with the force field of the nucleus, causing the
electron to slow down, diverting its course. The electron loses energy and
, changes direction. The energy lost is emitted as a bremsstrahlung photon,
and the photon energy is approximately half the difference between the
entering and exiting kinetic energy of the electron.
Explanation:
Bremsstrahlung (or "braking radiation") occurs when an incident electron
passes close to the nucleus of an atom and is slowed down by the
electrostatic force of the nucleus. This deceleration causes the electron to
lose energy, which is emitted as an x-ray photon. The energy of this photon
depends on how much the electron is slowed down. The more significant the
interaction with the nucleus, the higher the energy of the emitted photon.
3. Characteristic Interaction:
Answer: ✔✔
The incident electron interacts with an inner-shell electron, knocking it out
and continuing in a slightly different direction, creating a hole in the inner
shell, which makes the shell unstable.
Explanation:
In characteristic interactions, a high-speed electron from the cathode
strikes an inner-shell electron of the target material (typically tungsten),
ejecting it from the atom. This creates a vacancy in the inner shell (e.g., the
K-shell). An electron from a higher energy level then falls into the vacancy,
emitting an x-ray photon with energy equal to the difference in binding
energies between the shells. This process results in the emission of
characteristic x-rays specific to the target element.
4. Maximum allowed leakage from machine:
Answer: ✔✔ 100 mR per hour at 1 meter
Explanation:
The maximum allowable leakage radiation from an x-ray machine is
regulated to ensure the safety of radiographers and others near the
equipment. The maximum permitted leakage is 100 milliroentgens per
hour (mR/hr) measured at a distance of 1 meter from the tube housing.
