ARRT REGISTRY EXAM REVIEW EXAM 2026 NEWEST
EXAM PREP WITH COMPLETE QUESTIONS AND CORRECT
ANSWERS WITH RATIONALES | ALREADY GRADED A+|
|BRAND NEW VERSION!!
SECTION 1: RADIATION PROTECTION (Questions 1–75)
Q1. What is the primary purpose of beam restriction?
A) To increase image brightness
B) To minimize patient radiation exposure
C) To reduce examination time
D) To improve contrast resolution
CORRECT ANSWER: B
DETAILED RATIONALE: Beam restriction (collimation) directly reduces the volume
of irradiated tissue. According to the ALARA principle, this is the technologist's
first line of defense. While restricting the beam indirectly improves contrast
resolution (Option D) by reducing scatter, that is a secondary benefit. The
primary purpose, per FDA and NCRP, is patient dose reduction. Brightness
(Option A) is a monitor function, and examination time (Option C) is determined
by technique, not collimation.
Q2. According to NCRP regulations, leakage radiation from the x-ray tube must
NOT exceed:
A) 10 mR/hr
B) 50 mR/hr
C) 100 mR/hr
D) 500 mR/hr
CORRECT ANSWER: C
DETAILED RATIONALE: NCRP Report No. 102 mandates that leakage radiation
measured at 1 meter from the target must not exceed 100 mR/hr when the tube
is operated at maximum mA and kVp for the longest exposure. Option A (10
mR/hr) is the limit for fluoroscopic tabletop intensity. Option D is an outdated
limit.
1
,Q3. What is the minimum source-to-skin distance (SSD) allowed for a mobile
fluoroscopic unit?
A) 8 inches
B) 10 inches
C) 12 inches
D) 15 inches
CORRECT ANSWER: C
DETAILED RATIONALE: The FDA (21 CFR 1020.32) mandates 12 inches (30 cm) for
mobile fluoroscopic units to prevent deterministic skin effects. For stationary
fluoroscopy, the minimum SSD is 15 inches (38 cm). Stationary units allow
greater distance because they are fixed and can accommodate longer SIDs.
Q4. Pregnant technologists should not receive more than ___ rem for the
duration of the pregnancy.
A) 3.0 rem
B) 0.5 rem
C) 0.15 rem
D) 2.5 rem
CORRECT ANSWER: B
DETAILED RATIONALE: The NCRP recommends a maximum of 0.5 rem (500 mrem)
for the entire gestation period, with a monthly limit of 0.05 rem. This is
significantly lower than the annual occupational limit of 5 rem to protect the
developing fetus from stochastic and deterministic effects.
Q5. One rule of radiation protection is that radiation must scatter at LEAST
how many times before reaching the operator?
A) 1
B) 2
C) 3
D) 4
2
,CORRECT ANSWER: B
DETAILED RATIONALE: Scatter radiation must undergo at least two interactions
(two "bounces") before reaching the operator. Each scatter interaction reduces
the energy and intensity of the primary beam. Single-scatter (Compton) photons
still carry significant energy and are the main source of occupational exposure.
Q6. What is the annual effective dose limit for a radiologic technologist?
A) 1 rem (10 mSv)
B) 5 rem (50 mSv)
C) 10 rem (100 mSv)
D) 25 rem (250 mSv)
CORRECT ANSWER: B
DETAILED RATIONALE: The NCRP and ICRP set the occupational annual limit at 5
rem (50 mSv) for whole-body effective dose. This applies to declared pregnant
workers (0.5 rem total), the general public (0.1 rem), and extremities (50 rem).
Q7. What is the cardinal rule of radiation protection?
A) Shielding, distance, and collimation
B) Time, distance, and shielding
C) Filtration, collimation, and shielding
D) Time, collimation, and shielding
CORRECT ANSWER: B
DETAILED RATIONALE: The three cardinal principles are Time (minimize exposure
duration), Distance (maximize distance from source per inverse square law), and
Shielding (use lead aprons, barriers). Collimation and filtration are equipment
controls, not cardinal rules.
Q8. The inverse square law states that intensity is:
A) Directly proportional to the square of the distance
3
, B) Inversely proportional to the square of the distance
C) Directly proportional to the distance
D) Inversely proportional to the distance
CORRECT ANSWER: B
DETAILED RATIONALE: I1/I2 = (D2/D1)^2. As distance doubles, intensity decreases
to one-quarter. This is critical for technologists: doubling distance from the
patient reduces scatter exposure by 75%.
Q9. What is the primary source of occupational radiation exposure during
fluoroscopy?
A) Primary beam
B) Leakage radiation from the tube
C) Scatter radiation from the patient
D) Secondary radiation from the table
CORRECT ANSWER: C
DETAILED RATIONALE: The patient is the primary source of scatter radiation in
fluoroscopy. The primary beam is mostly absorbed by the patient, and leakage is
minimal due to housing shielding. Scatter originates at the patient's entry site
and is most intense on the technologist's side.
Q10. Which type of radiation interaction produces the most scatter in diagnostic
radiography?
A) Photoelectric absorption
B) Compton scattering
C) Coherent (Thomson) scattering
D) Pair production
CORRECT ANSWER: B
DETAILED RATIONALE: Compton scattering is the dominant interaction in the
diagnostic energy range (30–150 kVp). It produces a scattered photon with
reduced energy, which contributes to film fog and occupational exposure.
4
EXAM PREP WITH COMPLETE QUESTIONS AND CORRECT
ANSWERS WITH RATIONALES | ALREADY GRADED A+|
|BRAND NEW VERSION!!
SECTION 1: RADIATION PROTECTION (Questions 1–75)
Q1. What is the primary purpose of beam restriction?
A) To increase image brightness
B) To minimize patient radiation exposure
C) To reduce examination time
D) To improve contrast resolution
CORRECT ANSWER: B
DETAILED RATIONALE: Beam restriction (collimation) directly reduces the volume
of irradiated tissue. According to the ALARA principle, this is the technologist's
first line of defense. While restricting the beam indirectly improves contrast
resolution (Option D) by reducing scatter, that is a secondary benefit. The
primary purpose, per FDA and NCRP, is patient dose reduction. Brightness
(Option A) is a monitor function, and examination time (Option C) is determined
by technique, not collimation.
Q2. According to NCRP regulations, leakage radiation from the x-ray tube must
NOT exceed:
A) 10 mR/hr
B) 50 mR/hr
C) 100 mR/hr
D) 500 mR/hr
CORRECT ANSWER: C
DETAILED RATIONALE: NCRP Report No. 102 mandates that leakage radiation
measured at 1 meter from the target must not exceed 100 mR/hr when the tube
is operated at maximum mA and kVp for the longest exposure. Option A (10
mR/hr) is the limit for fluoroscopic tabletop intensity. Option D is an outdated
limit.
1
,Q3. What is the minimum source-to-skin distance (SSD) allowed for a mobile
fluoroscopic unit?
A) 8 inches
B) 10 inches
C) 12 inches
D) 15 inches
CORRECT ANSWER: C
DETAILED RATIONALE: The FDA (21 CFR 1020.32) mandates 12 inches (30 cm) for
mobile fluoroscopic units to prevent deterministic skin effects. For stationary
fluoroscopy, the minimum SSD is 15 inches (38 cm). Stationary units allow
greater distance because they are fixed and can accommodate longer SIDs.
Q4. Pregnant technologists should not receive more than ___ rem for the
duration of the pregnancy.
A) 3.0 rem
B) 0.5 rem
C) 0.15 rem
D) 2.5 rem
CORRECT ANSWER: B
DETAILED RATIONALE: The NCRP recommends a maximum of 0.5 rem (500 mrem)
for the entire gestation period, with a monthly limit of 0.05 rem. This is
significantly lower than the annual occupational limit of 5 rem to protect the
developing fetus from stochastic and deterministic effects.
Q5. One rule of radiation protection is that radiation must scatter at LEAST
how many times before reaching the operator?
A) 1
B) 2
C) 3
D) 4
2
,CORRECT ANSWER: B
DETAILED RATIONALE: Scatter radiation must undergo at least two interactions
(two "bounces") before reaching the operator. Each scatter interaction reduces
the energy and intensity of the primary beam. Single-scatter (Compton) photons
still carry significant energy and are the main source of occupational exposure.
Q6. What is the annual effective dose limit for a radiologic technologist?
A) 1 rem (10 mSv)
B) 5 rem (50 mSv)
C) 10 rem (100 mSv)
D) 25 rem (250 mSv)
CORRECT ANSWER: B
DETAILED RATIONALE: The NCRP and ICRP set the occupational annual limit at 5
rem (50 mSv) for whole-body effective dose. This applies to declared pregnant
workers (0.5 rem total), the general public (0.1 rem), and extremities (50 rem).
Q7. What is the cardinal rule of radiation protection?
A) Shielding, distance, and collimation
B) Time, distance, and shielding
C) Filtration, collimation, and shielding
D) Time, collimation, and shielding
CORRECT ANSWER: B
DETAILED RATIONALE: The three cardinal principles are Time (minimize exposure
duration), Distance (maximize distance from source per inverse square law), and
Shielding (use lead aprons, barriers). Collimation and filtration are equipment
controls, not cardinal rules.
Q8. The inverse square law states that intensity is:
A) Directly proportional to the square of the distance
3
, B) Inversely proportional to the square of the distance
C) Directly proportional to the distance
D) Inversely proportional to the distance
CORRECT ANSWER: B
DETAILED RATIONALE: I1/I2 = (D2/D1)^2. As distance doubles, intensity decreases
to one-quarter. This is critical for technologists: doubling distance from the
patient reduces scatter exposure by 75%.
Q9. What is the primary source of occupational radiation exposure during
fluoroscopy?
A) Primary beam
B) Leakage radiation from the tube
C) Scatter radiation from the patient
D) Secondary radiation from the table
CORRECT ANSWER: C
DETAILED RATIONALE: The patient is the primary source of scatter radiation in
fluoroscopy. The primary beam is mostly absorbed by the patient, and leakage is
minimal due to housing shielding. Scatter originates at the patient's entry site
and is most intense on the technologist's side.
Q10. Which type of radiation interaction produces the most scatter in diagnostic
radiography?
A) Photoelectric absorption
B) Compton scattering
C) Coherent (Thomson) scattering
D) Pair production
CORRECT ANSWER: B
DETAILED RATIONALE: Compton scattering is the dominant interaction in the
diagnostic energy range (30–150 kVp). It produces a scattered photon with
reduced energy, which contributes to film fog and occupational exposure.
4
