Exam 1 Radiographic Imaging and
Exposure with Accurate Solutions
Who discovered x-rays? - correct Answer-Dr. Wilhelm Conrad Roentgen
Where were x-rays discovered? - correct Answer-Wurzburg University, Germany
When were x-rays discovered? - correct Answer-November 8, 1895
Fluorescence - correct Answer-The instantaneous production of light resulting from the
interaction of some type of energy (x-rays in this case) and some element compound
(barium plantiocyanide).
List the two properties of x-rays. - correct Answer-It can behave both like waves and
particles.
Wavelength - correct Answer-Represents the number of waves passing a given point
per given unit of time. It's values are given in units of angstroms.
Frequency - correct Answer-The number of waves passing a given point per given unit
of time. Its values are given in units of Hertz (Hz).
Effective Focal Spot - correct Answer-Refers to the focal spot size as a measure directly
under the anode target.
Leakage Radiation - correct Answer-Refers to any x-ray, other than the primary beam,
that escapes the tube housing. The tube housing is lined with lead to shielding for
leakage radiation.
Focal Spot - correct Answer-Small area on t he target (anode) where x-rays are formed.
Bremsstrahlung Radiation - correct Answer-Happens at the anode:
- Projectile electron
- Avoids orbital electrons
- Gets very close to the nucleus
- Strong electrostatic force of nucleus causes electron to slow
- Then loses energy and changes direction
- Energy loss reappears as x-ray
- With below 70kVp (because tungsten), Brems happen 100% of the time
- About 85% of the time total
, Characteristic Radiation - correct Answer-Happens at anode
- Projectile electron interacts with inner k-shell electron
- Electron must have enough energy to eject electron from orbit (~6.95kVp)
- When K shell electron is ejected from orbit, out shell electron drops into open position
- Creates energy difference
- Which is emitted as x-rays (70kVp+)
- 15% of total interactions
Electric Current - correct Answer-The speed of the electrons in the tube current
determines the quality or energy of the x-rays that are produced. The quality of energy
of the x-rays, in turn, determines the penetrability of the primary beam- measured in kV.
Tube Current - correct Answer-Refers to the flow of electrons from the cathode to the
anode and measured in units called milliam
peres (mA).
kVp - correct Answer-- The kilovoltage determines the speed at which the electrons in
the tube current move. The speed of the electrons traveling from the cathode to the
anode increases as the kVp applied across the x-ray tube increases
- The higher the energy of the x-ray photons, the greater their penetrability, or ease with
which the move through tissue.
- Quality refers to the energy level of the radiation.
mAs - correct Answer-The millamperage is the unit used to measure tube current
(electrons between cathode and anode).
When current is applied to the filament, it causes a certain amount of thermionic
emission.
- Based on the amount of thermionic emission, there is a space charge consisting of a
certain number of electrons.
- The mA indicates the number of the electrons flowing in the tube per second- therefore
quantity.
Voltage Ripple - correct Answer-Describes the voltage waveforms of how much the
voltage varies during x-ray production.
Single Phase Unit - correct Answer-Said to be 100% because there is total variation in
the voltage waveform, from peak voltage to zero voltage.
Three phase unit - correct Answer-- 13% for a 6-pulse model
Exposure with Accurate Solutions
Who discovered x-rays? - correct Answer-Dr. Wilhelm Conrad Roentgen
Where were x-rays discovered? - correct Answer-Wurzburg University, Germany
When were x-rays discovered? - correct Answer-November 8, 1895
Fluorescence - correct Answer-The instantaneous production of light resulting from the
interaction of some type of energy (x-rays in this case) and some element compound
(barium plantiocyanide).
List the two properties of x-rays. - correct Answer-It can behave both like waves and
particles.
Wavelength - correct Answer-Represents the number of waves passing a given point
per given unit of time. It's values are given in units of angstroms.
Frequency - correct Answer-The number of waves passing a given point per given unit
of time. Its values are given in units of Hertz (Hz).
Effective Focal Spot - correct Answer-Refers to the focal spot size as a measure directly
under the anode target.
Leakage Radiation - correct Answer-Refers to any x-ray, other than the primary beam,
that escapes the tube housing. The tube housing is lined with lead to shielding for
leakage radiation.
Focal Spot - correct Answer-Small area on t he target (anode) where x-rays are formed.
Bremsstrahlung Radiation - correct Answer-Happens at the anode:
- Projectile electron
- Avoids orbital electrons
- Gets very close to the nucleus
- Strong electrostatic force of nucleus causes electron to slow
- Then loses energy and changes direction
- Energy loss reappears as x-ray
- With below 70kVp (because tungsten), Brems happen 100% of the time
- About 85% of the time total
, Characteristic Radiation - correct Answer-Happens at anode
- Projectile electron interacts with inner k-shell electron
- Electron must have enough energy to eject electron from orbit (~6.95kVp)
- When K shell electron is ejected from orbit, out shell electron drops into open position
- Creates energy difference
- Which is emitted as x-rays (70kVp+)
- 15% of total interactions
Electric Current - correct Answer-The speed of the electrons in the tube current
determines the quality or energy of the x-rays that are produced. The quality of energy
of the x-rays, in turn, determines the penetrability of the primary beam- measured in kV.
Tube Current - correct Answer-Refers to the flow of electrons from the cathode to the
anode and measured in units called milliam
peres (mA).
kVp - correct Answer-- The kilovoltage determines the speed at which the electrons in
the tube current move. The speed of the electrons traveling from the cathode to the
anode increases as the kVp applied across the x-ray tube increases
- The higher the energy of the x-ray photons, the greater their penetrability, or ease with
which the move through tissue.
- Quality refers to the energy level of the radiation.
mAs - correct Answer-The millamperage is the unit used to measure tube current
(electrons between cathode and anode).
When current is applied to the filament, it causes a certain amount of thermionic
emission.
- Based on the amount of thermionic emission, there is a space charge consisting of a
certain number of electrons.
- The mA indicates the number of the electrons flowing in the tube per second- therefore
quantity.
Voltage Ripple - correct Answer-Describes the voltage waveforms of how much the
voltage varies during x-ray production.
Single Phase Unit - correct Answer-Said to be 100% because there is total variation in
the voltage waveform, from peak voltage to zero voltage.
Three phase unit - correct Answer-- 13% for a 6-pulse model
