Patient Interactions and X-ray Emission Spectrum MCQs

Which of the following x-ray interactions occurs with inner-shell electrons and results in total absorption of the incoming photon?

A) Compton effect

B) Photoelectric effect

C) Coherent scattering

D) Pair production

B) Photoelectric effect

How does the atomic number (Z#) of tissue affect the probability of a photoelectric interaction?

A) Direct relationship (higher Z# increases probability)

B) Inverse relationship (higher Z# decreases probability)

C) There is no relationship

D) It decreases exponentially

A) Direct relationship (higher Z# increases probability)

Which interaction involves outer-shell electrons and is the primary source of occupational radiation exposure for healthcare workers?

A) Photoelectric effect

B) Coherent scattering

C) Compton effect

D) Photodisintegration

C) Compton effect

How does the atomic number of the absorber affect the occurrence of Compton scattering?

A) Direct relationship

B) Inverse relationship

C) It is not dependent on the atomic number

D) It increases proportionally with atomic number

C) It is not dependent on the atomic number

Which interaction occurs at very low energies, does not ionize the atom, and reemits a photon with the same energy, wavelength, and frequency?

A) Compton effect

B) Photoelectric effect

C) Coherent scattering

D) Pair production

C) Coherent scattering

On an x-ray emission spectrum, what does the continuous portion (the bell-shaped curve) represent?

A) Characteristic radiation

B) Bremsstrahlung radiation

C) Coherent scatter

D) Photoelectric absorption

B) Bremsstrahlung radiation

What does the discrete line on the x-ray emission spectrum represent?

A) Bremsstrahlung radiation

B) Compton scatter

C) K-characteristic radiation

D) Filtration level

C) K-characteristic radiation

How does doubling the mA or mAs affect the x-ray emission spectrum?

A) Shifts the curve to the right

B) Increases only the discrete line energy

C) Doubles the height (amplitude) of the curve

D) Decreases the average beam energy

C) Doubles the height (amplitude) of the curve

What is the overall effect of increasing tube filtration on the x-ray beam?

A) Decreases average energy and increases quantity

B) Increases average energy (quality) and decreases quantity

C) Increases both quality and quantity

D) Decreases both quality and quantity

B) Increases average energy (quality) and decreases quantity

How does an increase in kVp affect the continuous portion of the x-ray emission spectrum?

A) Decreases amplitude and shifts to the left

B) Increases amplitude and shifts the curve to the right

C) Increases amplitude but does not affect average energy

D) Only affects the discrete emission lines

B) Increases amplitude and shifts the curve to the right

What unit is used to measure x-ray beam quantity (intensity)?

A) Sievert (Sv)

B) Air kerma (Gy) or C/kg

C) Becquerel (Bq)

D) Effective dose

B) Air kerma (Gy) or C/kg

Which of the following is considered the primary factor controlling x-ray beam quantity?

A) kVp

B) Filtration

C) mAs

D) SID

C) mAs

If the mA is doubled, how is the x-ray beam quantity affected?

A) It is halved

B) It is doubled

C) It increases by a factor of four

D) It remains unchanged

B) It is doubled

Beam quantity varies with kVp as a function of which mathematical relationship?

A) Direct proportion

B) Inversely proportional

C) Directly proportional to the square of the ratio of change

D) Inversely proportional to the square of the distance

C) Directly proportional to the square of the ratio of change

According to the 15% rule, a 15% increase in kVp has the equivalent output effect as:

A) Doubling the mAs

B) Halving the mAs

C) Tripling the mAs

D) Reducing distance by half

A) Doubling the mAs

Which law states that the intensity of the x-ray beam is inversely proportional to the square of the distance?

A) Reciprocity Law

B) Ohm's Law

C) Inverse Square Law

D) Planck's Law

C) Inverse Square Law

What is the primary purpose of adding filtration to the x-ray beam?

A) To increase beam quantity

B) To remove low-energy photons and reduce patient dose

C) To increase the maximum energy of the beam

D) To increase scatter production

B) To remove low-energy photons and reduce patient dose

Which of the following terms describes the penetrating power of the x-ray beam?

A) Quantity

B) Quality

C) Intensity

D) Exposure

B) Quality

What is the primary controlling factor of x-ray beam quality?

A) mAs

B) SID

C) kVp

D) Focal spot size

C) kVp

What term describes x-ray beams produced with high kVp settings?

A) Soft beams

B) Hard (high-quality) beams

C) Coherent beams

D) Low-quality beams

B) Hard (high-quality) beams

How does filtration affect the average energy (quality) of the x-ray beam?

A) It decreases the average energy

B) It has no effect on quality

C) It increases the average energy

D) It reduces the beam to monoenergetic photons

C) It increases the average energy

What is defined as the thickness of absorbing material necessary to reduce the beam intensity to half its original value?

A) Half Value Layer (HVL)

B) Tenth Value Layer (TVL)

C) Linear attenuation coefficient

D) Grid ratio

A) Half Value Layer (HVL)

What is the normal HVL range for general diagnostic x-ray beams?

A) 1-2 mm Al

B) 3-5 mm Al

C) 6-8 mm Al

D) 10-12 mm Al

B) 3-5 mm Al

According to Title 21 CFR, x-ray tubes operating at 80 kVp must have a minimum HVL of:

A) 1.5 mm Al equivalency

B) 2.3 mm Al equivalency

C) 3.0 mm Al equivalency

D) 4.5 mm Al equivalency

B) 2.3 mm Al equivalency

What type of radiation emerges from the patient to form the radiographic image?

A) Primary radiation

B) Remnant (exit) radiation

C) Leakage radiation

D) Characteristic radiation

B) Remnant (exit) radiation

What is the term for the different ratio of absorption and transmission as x-rays pass through different body structures?

A) Attenuation

B) Differential attenuation

C) Coherent scattering

D) Spatial resolution

B) Differential attenuation

Attenuation is defined as the reduction in the number of x-ray photons in the beam due to:

A) Transmission only

B) Absorption only

C) Absorption and scattering

D) Increased filtration

C) Absorption and scattering

As tissue thickness increases by 4 to 5 cm, x-ray beam attenuation generally increases such that the transmitted beam is reduced by:

A) 15%

B) 25%

C) 50%

D) 75%

C) 50%

Which tissue type has a higher atomic number and absorbs more radiation than fat or air?

A) Muscle

B) Bone

C) Lung

D) Adipose tissue

B) Bone

How does increasing tissue density (compactness of particles) affect beam attenuation?

A) It decreases attenuation

B) It increases attenuation

C) It has no effect on attenuation

D) It increases transmission

B) It increases attenuation

For every change of 4 cm in tissue thickness, how should the radiographer adjust the mAs to maintain exposure?

A) Increase by 15%

B) Double or halve the mAs

C) Triple the mAs

D) Keep mAs constant and change SID

B) Double or halve the mAs

What effect does increasing kVp by 15% have on the probability of photoelectric absorption?

A) Increases the probability

B) Decreases the probability

C) Has no effect

D) Doubles the probability

B) Decreases the probability

The Compton effect is dependent on which of the following?

A) Atomic number of the tissue

B) Energy of the incoming photon

C) Thickness of the tissue

D) Density of the tissue

B) Energy of the incoming photon

What does remnant radiation consist of?

A) Primary radiation only

B) Transmitted and scattered radiation

C) Scattered radiation only

D) Absorbed radiation only

B) Transmitted and scattered radiation

How does increasing the kVp affect the relative proportion of Compton scatter versus photoelectric absorption?

A) It increases the proportion of photoelectric absorption

B) It increases the relative proportion of Compton scatter

C) It eliminates all Compton scattering

D) It has no effect on the ratio of interactions

B) It increases the relative proportion of Compton scatter

Why is using kVp to adjust beam quantity less desirable than using mAs?

A) kVp has no effect on beam quantity

B) kVp is too difficult to adjust on modern consoles

C) kVp also influences beam penetrability and scatter production

D) kVp changes do not affect patient dose

C) kVp also influences beam penetrability and scatter production

Comparing adipose tissue (fat) and muscle tissue, which statement is true regarding attenuation?

A) Adipose tissue is denser and attenuates more

B) Muscle tissue is denser and attenuates more

C) Both attenuate radiation equally

D) Muscle tissue transmits more radiation than adipose tissue

B) Muscle tissue is denser and attenuates more

What is defined as the difference between adjacent brightness levels/pixel values visible on the display monitor?

A) Subject contrast

B) Image contrast

C) Spatial resolution

D) Receptor exposure

B) Image contrast

Which digital post-processing feature is used to change image contrast?

A) Window level

B) Window width

C) Look-up table

D) Spatial frequency

B) Window width

Which digital post-processing feature is used to change image brightness?

A) Window level

B) Window width

C) Look-up table

D) Spatial frequency

A) Window level

What term describes an image with few gray levels, a short/narrow dynamic range, and a greater difference in brightness levels?

A) Long scale / Low contrast

B) Short scale / High contrast

C) High scale / Low contrast

D) Long scale / High contrast

B) Short scale / High contrast

How does an increase in kVp affect subject contrast?

A) Increases subject contrast (short scale)

B) Decreases subject contrast (long scale / increase grayscale)

C) Has no effect on subject contrast

D) Eliminates subject contrast entirely

B) Decreases subject contrast (long scale / increase grayscale)

To maintain receptor exposure when increasing x-ray photon quality (penetrability), you should:

A) Decrease kVp by 15% and double mAs

B) Increase kVp by 15% and double mAs

C) Increase kVp by 15% and halve mAs

D) Decrease kVp by 15% and halve mAs

C) Increase kVp by 15% and halve mAs

Why is raising kVp preferred over raising mAs when increasing radiographic technique?

A) It increases skin exposure

B) It achieves desired image quality while reducing patient exposure

C) It increases the number of low-energy photons

D) It decreases beam penetration

B) It achieves desired image quality while reducing patient exposure

Which type of contrast agent is radiopaque, has a high atomic number (Z#), and appears as high brightness/white on a digital image?

A) Positive contrast agent (like Barium)

B) Negative contrast agent (like Air)

C) Neutral contrast agent

D) Radiolucent agent

A) Positive contrast agent (like Barium)

Which of the following is NOT a primary cause of scatter radiation?

A) High levels of kVp

B) Large field sizes (decreased collimation)

C) Large body parts or thickness

D) High grid frequency

D) High grid frequency

Unwanted exposure to the image receptor resulting from Compton interactions is also known as:

A) Spatial resolution

B) Fog / Scatter

C) Attenuation

D) Latitude

B) Fog / Scatter

When grid ratio increases, what happens to receptor exposure?

A) Receptor exposure increases

B) Receptor exposure decreases

C) Receptor exposure remains unchanged

D) Receptor exposure doubles

B) Receptor exposure decreases

To maintain receptor exposure when switching to a higher grid ratio, the radiographer must:

A) Decrease mAs

B) Increase mAs

C) Decrease kVp

D) Increase SID

B) Increase mAs

What term describes the grid's ability to tolerate variations in central ray (CR) alignment without causing significant grid cutoff?

A) Grid ratio

B) Grid frequency

C) Grid latitude

D) Grid radius

C) Grid latitude

Which type of grid has lead strips that run parallel to the short axis of the grid?

A) Long-dimension grid

B) Short-dimension grid

C) Crossed grid

D) Focused grid

B) Short-dimension grid

What type of grid cutoff error occurs when the central ray is not centered to the middle of a focused grid?

A) Off-level

B) Off-center

C) Off-focus

D) Upside down

B) Off-center

What artifact is characterized by a "zebra" appearance and occurs when the sampling frequency of the CR reader is similar to the grid frequency?

A) Grid cutoff

B) Moiré effect (Aliasing)

C) Quantum mottle

D) Double exposure

B) Moiré effect (Aliasing)

How does increasing OID (Object-to-Image Distance) affect the amount of scatter radiation reaching the image receptor?

A) Increases scatter reaching the IR

B) Reduces scatter reaching the IR (air gap effect)

C) Has no effect on scatter

D) Eliminates primary beam transmission

B) Reduces scatter reaching the IR (air gap effect)

What is the effect of filtration on the average energy of the x-ray beam?

A) Decreases average energy

B) Increases average energy

C) Has no effect on average energy

D) Decreases beam penetration

B) Increases average energy

What is the minimum kVp setting typically set when a grid is used?

A) 50 kVp or higher

B) 60 kVp or higher

C) 70 kVp or higher

D) 90 kVp or higher

C) 70 kVp or higher

Which type of grid has lead strips angled to match the divergence of the x-ray beam?

A) Parallel grid

B) Linear grid

C) Focused grid

D) Crossed grid

C) Focused grid

Which grid error occurs when the tube is angled across the grid lines or the grid itself is tilted?

A) Off-level

B) Off-center

C) Off-focus

D) Upside down

A) Off-level

How does a lower ratio grid compare to a higher ratio grid regarding grid latitude?

A) Lower ratio grids have lower grid latitude

B) Lower ratio grids have higher grid latitude (more flexible)

C) Grid ratio has no effect on grid latitude

D) Higher ratio grids are more forgiving of misalignment

B) Lower ratio grids have higher grid latitude (more flexible)

How does scatter radiation affect the image contrast?

A) It increases image contrast

B) It decreases image contrast

C) It has no effect on image contrast

D) It increases the visibility of details

B) It decreases image contrast

Which of the following contrast agents is negative and radiolucent, appearing as low brightness/black on a digital image?

A) Barium

B) Iodine

C) Air

D) Gadolinium

C) Air

During a photoelectric interaction, what is the result of the electron cascade effect in tissue atoms?

A) High-energy primary photons

B) Low-energy secondary photons

C) High-energy scatter photons

D) Recoil electrons

B) Low-energy secondary photons

Which of the following describes the secondary radiation produced during a photoelectric cascade in low atomic number tissue atoms?

A) High energy and diagnostic

B) Low energy and non-diagnostic

C) High energy and non-diagnostic

D) Monoenergetic and diagnostic

B) Low energy and non-diagnostic

What are the three direct results of a Compton scattering event?

A) Photoelectron, characteristic photon, and excitation

B) Ionized atom, recoil electron, and a scattered photon

C) Positron, negatron, and annihilation radiation

D) Nuclear excitation, proton emission, and fission

B) Ionized atom, recoil electron, and a scattered photon

In coherent scattering, how does the reemitted scatter photon compare to the incoming x-ray photon?

A) It has half the energy

B) It has twice the frequency

C) It has the same energy, wavelength, and frequency

D) It has a longer wavelength and lower energy

C) It has the same energy, wavelength, and frequency

Which of the following is NOT one of the five factors that change the appearance of the x-ray emission spectrum?

A) Tube filtration

B) Generator type

C) Target material

D) Object-to-image distance (OID)

D) Object-to-image distance (OID)

On the x-ray emission spectrum, what represents the total number of Bremsstrahlung x-rays produced?

A) The position of the discrete line

B) The area under the continuous curve

C) The starting point on the y-axis

D) The x-axis intercept of the discrete line

B) The area under the continuous curve

Which K-shell characteristic x-ray energies are considered a useful portion of the x-ray beam?

A) 9, 11, and 12 keV

B) 30, 40, and 50 keV

C) 57, 66, 68, and 69 keV

D) 80, 90, and 100 keV

C) 57, 66, 68, and 69 keV

How does using a target material with a higher atomic number affect the x-ray emission spectrum?

A) Decreases the continuous curve height and shifts the discrete line left

B) Increases the curve amplitude and shifts the position of the discrete line

C) Decreases both continuous and discrete portions

D) Shifts only the continuous curve to the left without changing amplitude

B) Increases the curve amplitude and shifts the position of the discrete line

What happens to the kinetic energy of filament electrons when kVp is increased?

A) It decreases

B) It remains constant

C) It increases

D) It drops to zero

C) It increases

How does the Compton effect vary with the atomic number of the tissue?

A) Directly proportional

B) Inversely proportional

C) It is independent of the tissue atomic number

D) It varies as the square of the atomic number

C) It is independent of the tissue atomic number

If a radiographer decreases tissue thickness by 4 cm, how should the mAs be adjusted?

A) Double the mAs

B) Reduce the mAs to one-half

C) Increase kVp by 15%

D) Decrease kVp by 15%

B) Reduce the mAs to one-half