HESI Radiology Exit Exam prep
Version 2 Exam Questions and
Answers Practice Questions with
Solutions Newest | Already Graded
A+
Q1. Which process describes the electron-target interaction in
which most diagnostic x-rays are produced?
A. A filament electron strikes an orbital electron and removes it
from orbit.
B. Outer shell electrons have a higher energy level, but are not
ionized.
C. The filament electron misses all orbital electrons and interacts
with the target atom nucleus.
D. An outer shell electron fills an inner shell vacancy.
A: C. The filament electron misses all orbital electrons and
interacts with the target atom nucleus.
Rationale: Most diagnostic x-rays are produced
by bremsstrahlung interactions, where a high-speed electron
passes close to the nucleus, slows down, and loses energy in the
form of an x-ray photon. This occurs when the electron misses
orbital electrons and interacts with the nuclear field .
Q2. Which statements accurately describe the dose-response
relationship depicted in the graph? (Select three)
A. A response will occur only at doses of radiation above a specific
,point.
B. A radiation dose below a certain point on the graph is
completely safe.
C. A response will be directly proportional to the radiation dose.
D. All radiation doses carry some risk.
A: A, B, C.
Rationale: The graph describes a threshold (nonlinear) dose-
response model. Below the threshold, no effect is observed;
above it, response is directly proportional to dose. This contrasts
with the linear non-threshold model .
Q3. In the event that a pregnant patient is inadvertently
irradiated, who should perform the calculations necessary to
determine fetal dose?
A. Radiologist
B. Medical physicist
C. Radiation safety officer
D. Health physicist
A: B. Medical physicist.
Rationale: A radiologic physicist specializes in dose calculations
and should be consulted for fetal dose estimation following an
accidental exposure .
Q4. The annual effective dose equivalent limit for infrequent
exposures recommended by the NCRP for a member of the
general public is equal to how many rem(s)?
A. 5 rem
B. 15 rem
C. 0.5 rem
D. 1 rem
A: C. 0.5 rem (500 mrem).
,Rationale: The NCRP recommends a dose limit of 1 mSv (0.1
rem) per year for continuous exposure and 5 mSv (0.5 rem)
per year for infrequent exposure for the general public .
Q5. Which part of the x-ray circuit is controlled by adjusting
the milliamperage (mA) setting to produce heat for
thermionic emission?
A. High-voltage transformer
B. Filament circuit
C. Autotransformer
D. Rectifier circuit
A: B. Filament circuit.
Rationale: The mA selector controls the filament circuit current,
which heats the cathode filament to produce thermionic emission.
Higher mA = more electrons boiled off .
Q6. How many electrons occupy an electrically neutral oxygen
atom's outer shell? (Z=8)
A. 2
B. 4
C. 6
D. 8
A: C. 6.
Rationale: Oxygen has 8 total electrons. The first shell holds 2,
leaving 6 in the outer (valence) shell. The outer shell can hold
up to 8 .
Q7. If a radiographer receives an exposure of 0.05 mSv at 1.5
feet from a portable x-ray unit, what will the exposure be at 6
feet?
A. 0.2 mSv
, B. 0.0125 mSv
C. 0.003 mSv
D. 0.8 mSv
A: C. 0.003 mSv.
Rationale: Inverse square law: I₁/I₂ = (D₂/D₁)². (0.05)/x = (6/1.5)² =
(4)² = 16. x = 0.05/16 = 0.003125 mSv .
Q8. What is the result if the total lead content of a grid is
decreased?
A. Greater image contrast
B. Increased scatter absorption
C. Decreased scatter absorption
D. Higher patient dose
A: C. Decreased scatter absorption.
Rationale: Lead content determines grid efficiency. Less lead =
less scatter absorbed = more scatter reaches the IR, reducing
contrast .
Q9. Which component of radiographic noise in digital
imaging is controlled by the radiographer?
A. Structure mottle
B. Quantum mottle
C. Film graininess
D. Electronic noise
A: B. Quantum mottle.
Rationale: Quantum mottle (photon starvation) is controlled by
selecting appropriate mAs. Too low mAs increases quantum
noise. Structure mottle and electronic noise are equipment-
related .
Version 2 Exam Questions and
Answers Practice Questions with
Solutions Newest | Already Graded
A+
Q1. Which process describes the electron-target interaction in
which most diagnostic x-rays are produced?
A. A filament electron strikes an orbital electron and removes it
from orbit.
B. Outer shell electrons have a higher energy level, but are not
ionized.
C. The filament electron misses all orbital electrons and interacts
with the target atom nucleus.
D. An outer shell electron fills an inner shell vacancy.
A: C. The filament electron misses all orbital electrons and
interacts with the target atom nucleus.
Rationale: Most diagnostic x-rays are produced
by bremsstrahlung interactions, where a high-speed electron
passes close to the nucleus, slows down, and loses energy in the
form of an x-ray photon. This occurs when the electron misses
orbital electrons and interacts with the nuclear field .
Q2. Which statements accurately describe the dose-response
relationship depicted in the graph? (Select three)
A. A response will occur only at doses of radiation above a specific
,point.
B. A radiation dose below a certain point on the graph is
completely safe.
C. A response will be directly proportional to the radiation dose.
D. All radiation doses carry some risk.
A: A, B, C.
Rationale: The graph describes a threshold (nonlinear) dose-
response model. Below the threshold, no effect is observed;
above it, response is directly proportional to dose. This contrasts
with the linear non-threshold model .
Q3. In the event that a pregnant patient is inadvertently
irradiated, who should perform the calculations necessary to
determine fetal dose?
A. Radiologist
B. Medical physicist
C. Radiation safety officer
D. Health physicist
A: B. Medical physicist.
Rationale: A radiologic physicist specializes in dose calculations
and should be consulted for fetal dose estimation following an
accidental exposure .
Q4. The annual effective dose equivalent limit for infrequent
exposures recommended by the NCRP for a member of the
general public is equal to how many rem(s)?
A. 5 rem
B. 15 rem
C. 0.5 rem
D. 1 rem
A: C. 0.5 rem (500 mrem).
,Rationale: The NCRP recommends a dose limit of 1 mSv (0.1
rem) per year for continuous exposure and 5 mSv (0.5 rem)
per year for infrequent exposure for the general public .
Q5. Which part of the x-ray circuit is controlled by adjusting
the milliamperage (mA) setting to produce heat for
thermionic emission?
A. High-voltage transformer
B. Filament circuit
C. Autotransformer
D. Rectifier circuit
A: B. Filament circuit.
Rationale: The mA selector controls the filament circuit current,
which heats the cathode filament to produce thermionic emission.
Higher mA = more electrons boiled off .
Q6. How many electrons occupy an electrically neutral oxygen
atom's outer shell? (Z=8)
A. 2
B. 4
C. 6
D. 8
A: C. 6.
Rationale: Oxygen has 8 total electrons. The first shell holds 2,
leaving 6 in the outer (valence) shell. The outer shell can hold
up to 8 .
Q7. If a radiographer receives an exposure of 0.05 mSv at 1.5
feet from a portable x-ray unit, what will the exposure be at 6
feet?
A. 0.2 mSv
, B. 0.0125 mSv
C. 0.003 mSv
D. 0.8 mSv
A: C. 0.003 mSv.
Rationale: Inverse square law: I₁/I₂ = (D₂/D₁)². (0.05)/x = (6/1.5)² =
(4)² = 16. x = 0.05/16 = 0.003125 mSv .
Q8. What is the result if the total lead content of a grid is
decreased?
A. Greater image contrast
B. Increased scatter absorption
C. Decreased scatter absorption
D. Higher patient dose
A: C. Decreased scatter absorption.
Rationale: Lead content determines grid efficiency. Less lead =
less scatter absorbed = more scatter reaches the IR, reducing
contrast .
Q9. Which component of radiographic noise in digital
imaging is controlled by the radiographer?
A. Structure mottle
B. Quantum mottle
C. Film graininess
D. Electronic noise
A: B. Quantum mottle.
Rationale: Quantum mottle (photon starvation) is controlled by
selecting appropriate mAs. Too low mAs increases quantum
noise. Structure mottle and electronic noise are equipment-
related .
