Nuclear Medicine Technology Certification Practice
Exam
NMTCB / ARRT Board Review – 2026/2027 Edition
120 Practice Questions with Correct Answers &
Rationales
1. What is the annual occupational dose limit for the lens of the eye according to the
NRC?
A. 15 mSv
B. 50 mSv
C. 150 mSv
D. 500 mSv
Correct Answer: C. 150 mSv
Rationale: The NRC updated the occupational dose limit for the lens of the eye to 150
mSv/year (15 rem) in alignment with ICRP recommendations. This reduces the previous
limit of 500 mSv to better protect against radiation-induced cataracts. Option A is the
limit for embryo/fetus during pregnancy. Option B is the total effective dose equivalent
limit for whole body. Option D was the previous lens limit.
2. Which principle of radiation protection states that exposure should be kept "as low as
reasonably achievable"?
A. Time
B. Distance
C. Shielding
D. ALARA
,Correct Answer: D. ALARA
Rationale: ALARA (As Low As Reasonably Achievable) is the fundamental radiation
safety principle requiring optimization of protection considering economic and social
factors. Time, distance, and shielding are practical methods to implement ALARA but
are not the overarching principle itself.
3. A technologist receives 0.02 mR/hr at 1 meter from a patient injected with Tc-99m.
What is the approximate exposure at 2 meters?
A. 0.005 mR/hr
B. 0.01 mR/hr
C. 0.04 mR/hr
D. 0.08 mR/hr
Correct Answer: A. 0.005 mR/hr
Rationale: The inverse square law states intensity is inversely proportional to the
square of distance. Doubling distance (1m → 2m) reduces exposure to 1/4: 0.02 ÷ 4 =
0.005 mR/hr. This principle is critical for minimizing staff exposure during patient care.
4. Which personnel monitoring device provides the most accurate record of
occupational radiation exposure for nuclear medicine technologists?
A. Film badge
B. Pocket dosimeter
C. Thermoluminescent dosimeter (TLD)
D. Geiger-Müller counter
Correct Answer: C. Thermoluminescent dosimeter (TLD)
Rationale: TLDs offer superior accuracy, wide dose range, tissue equivalence, and re-
readability compared to film badges. Pocket dosimeters provide immediate readings
but are less reliable for official records. GM counters measure area radiation, not
personal dose.
,5. What is the primary purpose of a "radiation area" sign per NRC regulations?
A. To mark storage for radioactive materials
B. To indicate areas where radiation levels exceed 5 mrem/hr at 30 cm
C. To designate patient injection rooms
D. To identify waste disposal locations
Correct Answer: B. To indicate areas where radiation levels exceed 5 mrem/hr at 30
cm
Rationale: NRC 10 CFR 20.1902 defines a "Radiation Area" as any location where
radiation levels could result in an individual receiving >5 mrem in one hour at 30 cm.
This signage alerts personnel to implement protective measures. Higher thresholds
define "High Radiation Areas."
6. Which radionuclide requires the thickest lead shielding for equivalent activity?
A. Tc-99m (140 keV)
B. I-131 (364 keV)
C. F-18 (511 keV annihilation photons)
D. In-111 (171 & 245 keV)
Correct Answer: C. F-18 (511 keV annihilation photons)
Rationale: Higher energy photons require thicker shielding. F-18 emits 511 keV
annihilation photons from positron decay, requiring ~50% more lead thickness than I-
131's 364 keV gamma for equivalent attenuation. Tc-99m's 140 keV photons are most
easily shielded.
7. A pregnant technologist declares her pregnancy. What is the monthly dose limit to
the embryo/fetus?
A. 0.5 mSv
B. 5 mSv
C. 50 mSv
, D. No limit if declared
Correct Answer: A. 0.5 mSv
Rationale: NRC regulations limit embryo/fetus dose to 0.5 mSv (50 mrem) per month
once pregnancy is declared, with a total limit of 5 mSv for the entire gestation. This is
significantly lower than occupational limits to protect developing tissues.
8. Which action BEST minimizes radiation exposure during radiopharmaceutical
administration?
A. Wearing two lead aprons
B. Using tongs or syringe shields
C. Standing behind a lead barrier for all procedures
D. Limiting patient contact time to <1 minute
Correct Answer: B. Using tongs or syringe shields
Rationale: Syringe shields reduce hand exposure by 90%+ during injection, directly
addressing the highest-exposure task. While time/distance/shielding are all important,
syringe shielding provides the most practical, high-impact protection for routine
injections.
9. What is the half-value layer (HVL) primarily used to assess?
A. Radiopharmaceutical purity
B. Shielding effectiveness
C. Camera resolution
D. Patient dose calculation
Correct Answer: B. Shielding effectiveness
Rationale: HVL measures the thickness of material required to reduce radiation
intensity by 50%, directly quantifying shielding performance. It is critical for designing
safe storage, transport, and work areas. It does not assess radiopharmaceutical quality
or imaging parameters.
Exam
NMTCB / ARRT Board Review – 2026/2027 Edition
120 Practice Questions with Correct Answers &
Rationales
1. What is the annual occupational dose limit for the lens of the eye according to the
NRC?
A. 15 mSv
B. 50 mSv
C. 150 mSv
D. 500 mSv
Correct Answer: C. 150 mSv
Rationale: The NRC updated the occupational dose limit for the lens of the eye to 150
mSv/year (15 rem) in alignment with ICRP recommendations. This reduces the previous
limit of 500 mSv to better protect against radiation-induced cataracts. Option A is the
limit for embryo/fetus during pregnancy. Option B is the total effective dose equivalent
limit for whole body. Option D was the previous lens limit.
2. Which principle of radiation protection states that exposure should be kept "as low as
reasonably achievable"?
A. Time
B. Distance
C. Shielding
D. ALARA
,Correct Answer: D. ALARA
Rationale: ALARA (As Low As Reasonably Achievable) is the fundamental radiation
safety principle requiring optimization of protection considering economic and social
factors. Time, distance, and shielding are practical methods to implement ALARA but
are not the overarching principle itself.
3. A technologist receives 0.02 mR/hr at 1 meter from a patient injected with Tc-99m.
What is the approximate exposure at 2 meters?
A. 0.005 mR/hr
B. 0.01 mR/hr
C. 0.04 mR/hr
D. 0.08 mR/hr
Correct Answer: A. 0.005 mR/hr
Rationale: The inverse square law states intensity is inversely proportional to the
square of distance. Doubling distance (1m → 2m) reduces exposure to 1/4: 0.02 ÷ 4 =
0.005 mR/hr. This principle is critical for minimizing staff exposure during patient care.
4. Which personnel monitoring device provides the most accurate record of
occupational radiation exposure for nuclear medicine technologists?
A. Film badge
B. Pocket dosimeter
C. Thermoluminescent dosimeter (TLD)
D. Geiger-Müller counter
Correct Answer: C. Thermoluminescent dosimeter (TLD)
Rationale: TLDs offer superior accuracy, wide dose range, tissue equivalence, and re-
readability compared to film badges. Pocket dosimeters provide immediate readings
but are less reliable for official records. GM counters measure area radiation, not
personal dose.
,5. What is the primary purpose of a "radiation area" sign per NRC regulations?
A. To mark storage for radioactive materials
B. To indicate areas where radiation levels exceed 5 mrem/hr at 30 cm
C. To designate patient injection rooms
D. To identify waste disposal locations
Correct Answer: B. To indicate areas where radiation levels exceed 5 mrem/hr at 30
cm
Rationale: NRC 10 CFR 20.1902 defines a "Radiation Area" as any location where
radiation levels could result in an individual receiving >5 mrem in one hour at 30 cm.
This signage alerts personnel to implement protective measures. Higher thresholds
define "High Radiation Areas."
6. Which radionuclide requires the thickest lead shielding for equivalent activity?
A. Tc-99m (140 keV)
B. I-131 (364 keV)
C. F-18 (511 keV annihilation photons)
D. In-111 (171 & 245 keV)
Correct Answer: C. F-18 (511 keV annihilation photons)
Rationale: Higher energy photons require thicker shielding. F-18 emits 511 keV
annihilation photons from positron decay, requiring ~50% more lead thickness than I-
131's 364 keV gamma for equivalent attenuation. Tc-99m's 140 keV photons are most
easily shielded.
7. A pregnant technologist declares her pregnancy. What is the monthly dose limit to
the embryo/fetus?
A. 0.5 mSv
B. 5 mSv
C. 50 mSv
, D. No limit if declared
Correct Answer: A. 0.5 mSv
Rationale: NRC regulations limit embryo/fetus dose to 0.5 mSv (50 mrem) per month
once pregnancy is declared, with a total limit of 5 mSv for the entire gestation. This is
significantly lower than occupational limits to protect developing tissues.
8. Which action BEST minimizes radiation exposure during radiopharmaceutical
administration?
A. Wearing two lead aprons
B. Using tongs or syringe shields
C. Standing behind a lead barrier for all procedures
D. Limiting patient contact time to <1 minute
Correct Answer: B. Using tongs or syringe shields
Rationale: Syringe shields reduce hand exposure by 90%+ during injection, directly
addressing the highest-exposure task. While time/distance/shielding are all important,
syringe shielding provides the most practical, high-impact protection for routine
injections.
9. What is the half-value layer (HVL) primarily used to assess?
A. Radiopharmaceutical purity
B. Shielding effectiveness
C. Camera resolution
D. Patient dose calculation
Correct Answer: B. Shielding effectiveness
Rationale: HVL measures the thickness of material required to reduce radiation
intensity by 50%, directly quantifying shielding performance. It is critical for designing
safe storage, transport, and work areas. It does not assess radiopharmaceutical quality
or imaging parameters.
