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HESI Radiology Exit Exam prep Version 1 2026-2027 BANK
QUESTIONS WITH DETAILED VERIFIED ANSWERS EXAM
QUESTIONS WILL COME FROM HERE (100% CORRECT
ANSWERS A+ GRADED
1. Which interaction of x-ray photons with matter is primarily
responsible for producing the radiographic image?
A. Photoelectric effect
B. Compton scattering
C. Pair production
D. Coherent scattering
Answer: A. Photoelectric effect. The photoelectric effect involves
complete absorption of the incident x-ray photon, leading to
differential absorption based on tissue density and atomic number. This
differential absorption creates the contrast that forms the radiographic
image.
2. The primary source of occupational radiation exposure to a radiologic
technologist is from which of the following?
A. The primary beam
B. Leakage radiation from the tube housing
C. Compton scattered photons from the patient
D. Off-focus radiation
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Answer: C. Compton scattered photons from the patient. During an
exposure, the patient becomes the largest source of scattered
radiation. The technologist, when standing behind a protective barrier
or wearing lead apparel, is exposed mainly to this secondary radiation.
3. Which of the following grid ratios will most effectively clean up
scatter radiation but also requires the highest patient dose?
A. 5:1
B. 8:1
C. 10:1
D. 16:1
Answer: D. 16:1. Higher grid ratios have more lead strips perpendicular
to the interspace material, making them more effective at absorbing
scattered radiation. However, they require a significant increase in
milliampere-seconds (mAs) to maintain adequate image receptor
exposure, thus increasing patient dose.
4. What is the primary function of the AEC (Automatic Exposure
Control) system?
A. To automatically select the optimal kilovoltage peak (kVp)
B. To reduce patient motion by shortening exposure time
C. To terminate the exposure once a predetermined amount of
radiation is transmitted to the image receptor
D. To automatically adjust the source-to-image distance (SID)
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Answer: C. To terminate the exposure once a predetermined amount of
radiation is transmitted to the image receptor. The AEC system, using
ionization chambers, measures radiation exiting the patient and stops
the timer when a sufficient signal has been received to produce a
diagnostic image.
5. According to the inverse square law, if the source-to-image distance
(SID) is doubled, the radiation intensity at the image receptor will:
A. Be doubled
B. Be reduced to one-half
C. Be reduced to one-quarter
D. Remain unchanged
Answer: C. Be reduced to one-quarter. The inverse square law states
that intensity is inversely proportional to the square of the distance (I ∝
1/D^2). If distance is doubled, intensity becomes 1/(2^2) = 1/4 of its
original value.
6. Which of the following describes the process of thermionic emission
in an x-ray tube?
A. The production of x-rays when high-speed electrons hit the anode
B. The boiling off of electrons from the filament when it is heated
C. The focusing of electrons into a beam by the focusing cup
D. The rotation of the anode to dissipate heat
Answer: B. The boiling off of electrons from the filament when it is
heated. Passing a high current through the tungsten filament raises its
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temperature, imparting sufficient kinetic energy to the outer-shell
electrons to overcome the binding energy and escape the metal
surface. This cloud of electrons is the source of the tube current.
7. Which component of the x-ray tube is the actual source of the useful
x-ray beam?
A. The filament
B. The focusing cup
C. The actual focal spot
D. The effective focal spot
Answer: C. The actual focal spot. The actual focal spot is the physical
area on the anode target that is bombarded by the electron stream.
The effective focal spot is the projection of this area onto the patient
and image receptor, influenced by the anode angle.
8. The line-focus principle explains how:
A. The anode angle is directly proportional to the actual focal spot size
B. The anode angle is inversely proportional to the effective focal spot
size
C. By angling the anode target, the effective focal spot is made much
smaller than the actual focal spot, while maintaining a large heat-
dissipation area
D. The cathode filament is angled to produce a uniform electron beam
Answer: C. By angling the anode target, the effective focal spot is made
much smaller than the actual focal spot, while maintaining a large heat-
HESI Radiology Exit Exam prep Version 1 2026-2027 BANK
QUESTIONS WITH DETAILED VERIFIED ANSWERS EXAM
QUESTIONS WILL COME FROM HERE (100% CORRECT
ANSWERS A+ GRADED
1. Which interaction of x-ray photons with matter is primarily
responsible for producing the radiographic image?
A. Photoelectric effect
B. Compton scattering
C. Pair production
D. Coherent scattering
Answer: A. Photoelectric effect. The photoelectric effect involves
complete absorption of the incident x-ray photon, leading to
differential absorption based on tissue density and atomic number. This
differential absorption creates the contrast that forms the radiographic
image.
2. The primary source of occupational radiation exposure to a radiologic
technologist is from which of the following?
A. The primary beam
B. Leakage radiation from the tube housing
C. Compton scattered photons from the patient
D. Off-focus radiation
,2|Page
Answer: C. Compton scattered photons from the patient. During an
exposure, the patient becomes the largest source of scattered
radiation. The technologist, when standing behind a protective barrier
or wearing lead apparel, is exposed mainly to this secondary radiation.
3. Which of the following grid ratios will most effectively clean up
scatter radiation but also requires the highest patient dose?
A. 5:1
B. 8:1
C. 10:1
D. 16:1
Answer: D. 16:1. Higher grid ratios have more lead strips perpendicular
to the interspace material, making them more effective at absorbing
scattered radiation. However, they require a significant increase in
milliampere-seconds (mAs) to maintain adequate image receptor
exposure, thus increasing patient dose.
4. What is the primary function of the AEC (Automatic Exposure
Control) system?
A. To automatically select the optimal kilovoltage peak (kVp)
B. To reduce patient motion by shortening exposure time
C. To terminate the exposure once a predetermined amount of
radiation is transmitted to the image receptor
D. To automatically adjust the source-to-image distance (SID)
,3|Page
Answer: C. To terminate the exposure once a predetermined amount of
radiation is transmitted to the image receptor. The AEC system, using
ionization chambers, measures radiation exiting the patient and stops
the timer when a sufficient signal has been received to produce a
diagnostic image.
5. According to the inverse square law, if the source-to-image distance
(SID) is doubled, the radiation intensity at the image receptor will:
A. Be doubled
B. Be reduced to one-half
C. Be reduced to one-quarter
D. Remain unchanged
Answer: C. Be reduced to one-quarter. The inverse square law states
that intensity is inversely proportional to the square of the distance (I ∝
1/D^2). If distance is doubled, intensity becomes 1/(2^2) = 1/4 of its
original value.
6. Which of the following describes the process of thermionic emission
in an x-ray tube?
A. The production of x-rays when high-speed electrons hit the anode
B. The boiling off of electrons from the filament when it is heated
C. The focusing of electrons into a beam by the focusing cup
D. The rotation of the anode to dissipate heat
Answer: B. The boiling off of electrons from the filament when it is
heated. Passing a high current through the tungsten filament raises its
, 4|Page
temperature, imparting sufficient kinetic energy to the outer-shell
electrons to overcome the binding energy and escape the metal
surface. This cloud of electrons is the source of the tube current.
7. Which component of the x-ray tube is the actual source of the useful
x-ray beam?
A. The filament
B. The focusing cup
C. The actual focal spot
D. The effective focal spot
Answer: C. The actual focal spot. The actual focal spot is the physical
area on the anode target that is bombarded by the electron stream.
The effective focal spot is the projection of this area onto the patient
and image receptor, influenced by the anode angle.
8. The line-focus principle explains how:
A. The anode angle is directly proportional to the actual focal spot size
B. The anode angle is inversely proportional to the effective focal spot
size
C. By angling the anode target, the effective focal spot is made much
smaller than the actual focal spot, while maintaining a large heat-
dissipation area
D. The cathode filament is angled to produce a uniform electron beam
Answer: C. By angling the anode target, the effective focal spot is made
much smaller than the actual focal spot, while maintaining a large heat-
