Nuclear Medicine Technology Certification Practice Exam
NMTCB / ARRT Style
2026/2027 Edition
Total Questions: 120
Time Limit: 4 hours (simulated)
Passing Score: 75% (90 correct)
Section 1: Radiation Safety & Protection (Questions 1–20)
1. Which of the following is the primary annual occupational effective dose limit for a
nuclear medicine technologist (whole body) as recommended by the NRC?
A. 5 mSv
B. 50 mSv
C. 500 mSv
D. 1 mSv
Correct Answer: B. 50 mSv
Rationale: The NRC occupational dose limit for whole-body exposure is 5 rem (50 mSv).
The public limit is 1 mSv.
2. Time, distance, and shielding are the cardinal principles of radiation protection.
Doubling the distance from a point source of radiation reduces exposure by a factor of:
A. 2
B. 4
C. 1/2
D. 8
Correct Answer: B. 4
Rationale: Inverse square law: Intensity ∝ 1/d². Doubling distance reduces exposure to
1/4.
,3. Which shielding material is most effective for gamma photons from Tc-99m (140
keV)?
A. Lead
B. Plastic
C. Aluminum
D. Water
Correct Answer: A. Lead
Rationale: Lead has high atomic number and density, ideal for gamma energies <200
keV.
4. A technologist receives a whole-body dose of 2 mSv per month. What is the annual
dose, assuming no other exposures?
A. 12 mSv
B. 24 mSv
C. 48 mSv
D. 6 mSv
Correct Answer: B. 24 mSv
Rationale: 2 mSv × 12 months = 24 mSv, below the 50 mSv limit.
5. ALARA stands for:
A. As Low As Reasonably Achievable
B. As Low As Readily Available
C. Always Lower Absolute Radiation Average
D. Acceptable Limits for Acute Radiation Accidents
Correct Answer: A. As Low As Reasonably Achievable
Rationale: ALARA is the fundamental radiation safety principle to minimize exposure.
6. Which type of radiation interaction with matter is primarily responsible for producing
an image in a gamma camera?
A. Photoelectric effect
B. Compton scatter
C. Pair production
D. Coherent scatter
,Correct Answer: A. Photoelectric effect
Rationale: Photoelectric absorption gives positional information; Compton scatter
degrades image contrast.
7. The maximum allowed dose to a pregnant declared pregnant worker (fetus) per
month is:
A. 0.5 mSv
B. 5 mSv
C. 0.05 mSv
D. 1 mSv
Correct Answer: A. 0.5 mSv
Rationale: NRC: 5 mSv total gestation, not to exceed 0.5 mSv per month.
8. A contaminated technologist’s hand reads 2000 cpm on a pancake GM probe
(efficiency 20% for Tc-99m). Approximate activity in nCi?
A. 0.45 nCi
B. 45 nCi
C. 450 nCi
D. 4.5 nCi
Correct Answer: B. 45 nCi
Rationale: 2000 cpm / 0.20 = 10,000 dpm; 10,000 dpm / 2.22e6 dpm/µCi = 0.0045 µCi =
45 nCi.
9. Which is the most appropriate action if a drop of blood containing 1 mCi of Tc-99m
spills on the floor?
A. Wipe with paper towel and discard in regular trash
B. Notify RSO, cordon off area, use absorbent pads, survey
C. Ignore if background reading is normal
D. Use bleach and mop immediately
Correct Answer: B. Notify RSO, cordon off area, use absorbent pads, survey
Rationale: Spills >1 mCi require RSO notification and proper contamination control.
10. The term “rem” is equivalent to:
A. rad × QF
, B. Gy × Sv
C. R × BEF
D. mGy × Wr
Correct Answer: A. rad × QF
Rationale: rem = rad × quality factor (now Sievert = Gy × Wr).
11. Which of the following will most effectively reduce occupational exposure during a
Tc-99m injection?
A. Using a lead-lined syringe shield
B. Wearing double gloves
C. Using a longer needle
D. Injecting rapidly
Correct Answer: A. Using a lead-lined syringe shield
Rationale: Shielding directly attenuates gamma rays; gloves protect against
contamination only.
12. A patient who received I-131 sodium iodide for thyroid cancer therapy (100 mCi) is
being discharged. Which of the following is a required instruction?
A. Avoid contact with pregnant women for 24 hours
B. Sleep in a separate bed for 3–7 days
C. No special precautions needed
D. Double-flush toilet only once
Correct Answer: B. Sleep in a separate bed for 3–7 days
Rationale: NRC release criteria include minimizing exposure to others; separate bed for
several days.
13. Which survey instrument is best for detecting low-energy (<30 keV) contamination?
A. Ion chamber
B. NaI(Tl) scintillation probe
C. GM pancake
D. Cutie pie
Correct Answer: C. GM pancake
Rationale: GM pancake has thin window, high sensitivity for low-energy beta/gamma.
NMTCB / ARRT Style
2026/2027 Edition
Total Questions: 120
Time Limit: 4 hours (simulated)
Passing Score: 75% (90 correct)
Section 1: Radiation Safety & Protection (Questions 1–20)
1. Which of the following is the primary annual occupational effective dose limit for a
nuclear medicine technologist (whole body) as recommended by the NRC?
A. 5 mSv
B. 50 mSv
C. 500 mSv
D. 1 mSv
Correct Answer: B. 50 mSv
Rationale: The NRC occupational dose limit for whole-body exposure is 5 rem (50 mSv).
The public limit is 1 mSv.
2. Time, distance, and shielding are the cardinal principles of radiation protection.
Doubling the distance from a point source of radiation reduces exposure by a factor of:
A. 2
B. 4
C. 1/2
D. 8
Correct Answer: B. 4
Rationale: Inverse square law: Intensity ∝ 1/d². Doubling distance reduces exposure to
1/4.
,3. Which shielding material is most effective for gamma photons from Tc-99m (140
keV)?
A. Lead
B. Plastic
C. Aluminum
D. Water
Correct Answer: A. Lead
Rationale: Lead has high atomic number and density, ideal for gamma energies <200
keV.
4. A technologist receives a whole-body dose of 2 mSv per month. What is the annual
dose, assuming no other exposures?
A. 12 mSv
B. 24 mSv
C. 48 mSv
D. 6 mSv
Correct Answer: B. 24 mSv
Rationale: 2 mSv × 12 months = 24 mSv, below the 50 mSv limit.
5. ALARA stands for:
A. As Low As Reasonably Achievable
B. As Low As Readily Available
C. Always Lower Absolute Radiation Average
D. Acceptable Limits for Acute Radiation Accidents
Correct Answer: A. As Low As Reasonably Achievable
Rationale: ALARA is the fundamental radiation safety principle to minimize exposure.
6. Which type of radiation interaction with matter is primarily responsible for producing
an image in a gamma camera?
A. Photoelectric effect
B. Compton scatter
C. Pair production
D. Coherent scatter
,Correct Answer: A. Photoelectric effect
Rationale: Photoelectric absorption gives positional information; Compton scatter
degrades image contrast.
7. The maximum allowed dose to a pregnant declared pregnant worker (fetus) per
month is:
A. 0.5 mSv
B. 5 mSv
C. 0.05 mSv
D. 1 mSv
Correct Answer: A. 0.5 mSv
Rationale: NRC: 5 mSv total gestation, not to exceed 0.5 mSv per month.
8. A contaminated technologist’s hand reads 2000 cpm on a pancake GM probe
(efficiency 20% for Tc-99m). Approximate activity in nCi?
A. 0.45 nCi
B. 45 nCi
C. 450 nCi
D. 4.5 nCi
Correct Answer: B. 45 nCi
Rationale: 2000 cpm / 0.20 = 10,000 dpm; 10,000 dpm / 2.22e6 dpm/µCi = 0.0045 µCi =
45 nCi.
9. Which is the most appropriate action if a drop of blood containing 1 mCi of Tc-99m
spills on the floor?
A. Wipe with paper towel and discard in regular trash
B. Notify RSO, cordon off area, use absorbent pads, survey
C. Ignore if background reading is normal
D. Use bleach and mop immediately
Correct Answer: B. Notify RSO, cordon off area, use absorbent pads, survey
Rationale: Spills >1 mCi require RSO notification and proper contamination control.
10. The term “rem” is equivalent to:
A. rad × QF
, B. Gy × Sv
C. R × BEF
D. mGy × Wr
Correct Answer: A. rad × QF
Rationale: rem = rad × quality factor (now Sievert = Gy × Wr).
11. Which of the following will most effectively reduce occupational exposure during a
Tc-99m injection?
A. Using a lead-lined syringe shield
B. Wearing double gloves
C. Using a longer needle
D. Injecting rapidly
Correct Answer: A. Using a lead-lined syringe shield
Rationale: Shielding directly attenuates gamma rays; gloves protect against
contamination only.
12. A patient who received I-131 sodium iodide for thyroid cancer therapy (100 mCi) is
being discharged. Which of the following is a required instruction?
A. Avoid contact with pregnant women for 24 hours
B. Sleep in a separate bed for 3–7 days
C. No special precautions needed
D. Double-flush toilet only once
Correct Answer: B. Sleep in a separate bed for 3–7 days
Rationale: NRC release criteria include minimizing exposure to others; separate bed for
several days.
13. Which survey instrument is best for detecting low-energy (<30 keV) contamination?
A. Ion chamber
B. NaI(Tl) scintillation probe
C. GM pancake
D. Cutie pie
Correct Answer: C. GM pancake
Rationale: GM pancake has thin window, high sensitivity for low-energy beta/gamma.
