NMTCB RS 2026 Exam Prep: Radiation Safety
Certification Practice Questions with Answer
Rationales Dosimetry | Regulations | Exposure
Control | Radioactive Materials | Clinical Review
Section 1: Dosimetry & Personnel Monitoring (Questions 1–15)
Question 1
The annual occupational whole-body dose limit for radiation workers under 10
CFR Part 20 is:
A) 1 mSv (0.1 rem)
B) 5 mSv (0.5 rem)
C) 50 mSv (5 rem)
D) 500 mSv (50 rem)
Answer: C
Rationale: The NRC establishes the annual occupational Total Effective Dose
Equivalent (TEDE) limit at 50 mSv (5 rem) per year. This limit applies to the sum of
external and internal doses. It is significantly higher than the public dose limit of 1
mSv per year .
Question 2
The annual occupational dose limit for the lens of the eye is:
A) 20 mSv (2 rem)
B) 50 mSv (5 rem)
C) 150 mSv (15 rem)
D) 500 mSv (50 rem)
Answer: C
,Rationale: The current regulatory limit for the lens of the eye for occupational
exposure is 150 mSv (15 rem) per year. This limit exists to prevent deterministic
effects such as radiation-induced cataracts. Note that some recent guidance
recommends lower limits, but the federal regulatory limit remains 150 mSv .
Question 3
The annual dose limit for the skin and extremities for occupational workers is:
A) 50 mSv (5 rem)
B) 150 mSv (15 rem)
C) 250 mSv (25 rem)
D) 500 mSv (50 rem)
Answer: D
Rationale: The NRC sets the annual dose limit for the skin (shallow dose
equivalent) and extremities (hands, forearms, feet, ankles) at 500 mSv (50 rem)
per year. This higher limit reflects the lower radiation sensitivity of these tissues
compared to the whole body .
Question 4
The dose limit for a declared pregnant radiation worker during the entire
gestation period is:
A) 0.5 mSv (50 mrem)
B) 5 mSv (500 mrem)
C) 50 mSv (5 rem)
D) 500 mSv (50 rem)
Answer: B
Rationale: The NRC requires that the dose to the embryo/fetus of a declared
pregnant worker not exceed 5 mSv (500 mrem) during the entire gestation period.
,This is significantly lower than the occupational worker limit to protect the
developing fetus from radiation effects .
Question 5
The annual dose limit for members of the public in unrestricted areas is:
A) 1 mSv (0.1 rem)
B) 5 mSv (0.5 rem)
C) 10 mSv (1 rem)
D) 50 mSv (5 rem)
Answer: A
Rationale: The NRC limits public exposure in unrestricted areas to 1 mSv (0.1 rem)
per year. Additionally, the dose rate in any unrestricted area must not exceed 2
mrem (0.02 mSv) in any one hour .
Question 6
The dose rate limit in an unrestricted area is:
A) 0.1 mrem/hr
B) 2 mrem/hr
C) 5 mrem/hr
D) 10 mrem/hr
Answer: B
Rationale: An unrestricted area is defined as one where a person could not
receive a dose in excess of 2 mrem/hr. Restricted areas are controlled-access
areas for radiation protection purposes .
Question 7
, Which dosimeter type uses thermally stimulated luminescence to record dose?
A) Film badge
B) TLD (Thermoluminescent dosimeter)
C) OSL (Optically stimulated luminescence) badge
D) Geiger-Müller tube
Answer: B
Rationale: TLDs store energy in crystal lattice defects and release light when
heated, with the light output proportional to the absorbed dose. OSL badges use
optically stimulated luminescence (light stimulation rather than heat), while film
badges use photographic film .
Question 8
A radiation worker's whole-body dosimeter reads 3 mSv for the year. Which
statement is true?
A) The worker has exceeded the annual occupational limit
B) The worker is well within the annual limit of 50 mSv
C) The worker must be immediately removed from radiation work
D) The worker has exceeded the public dose limit
Answer: B
Rationale: The annual occupational whole-body dose limit is 50 mSv (5 rem) per
year. A dose of 3 mSv is well below this limit and represents a typical annual dose
for a nuclear medicine technologist. The public dose limit of 1 mSv applies to
members of the general public, not radiation workers .
Question 9
The term "committed effective dose equivalent (CEDE)" refers to:
Certification Practice Questions with Answer
Rationales Dosimetry | Regulations | Exposure
Control | Radioactive Materials | Clinical Review
Section 1: Dosimetry & Personnel Monitoring (Questions 1–15)
Question 1
The annual occupational whole-body dose limit for radiation workers under 10
CFR Part 20 is:
A) 1 mSv (0.1 rem)
B) 5 mSv (0.5 rem)
C) 50 mSv (5 rem)
D) 500 mSv (50 rem)
Answer: C
Rationale: The NRC establishes the annual occupational Total Effective Dose
Equivalent (TEDE) limit at 50 mSv (5 rem) per year. This limit applies to the sum of
external and internal doses. It is significantly higher than the public dose limit of 1
mSv per year .
Question 2
The annual occupational dose limit for the lens of the eye is:
A) 20 mSv (2 rem)
B) 50 mSv (5 rem)
C) 150 mSv (15 rem)
D) 500 mSv (50 rem)
Answer: C
,Rationale: The current regulatory limit for the lens of the eye for occupational
exposure is 150 mSv (15 rem) per year. This limit exists to prevent deterministic
effects such as radiation-induced cataracts. Note that some recent guidance
recommends lower limits, but the federal regulatory limit remains 150 mSv .
Question 3
The annual dose limit for the skin and extremities for occupational workers is:
A) 50 mSv (5 rem)
B) 150 mSv (15 rem)
C) 250 mSv (25 rem)
D) 500 mSv (50 rem)
Answer: D
Rationale: The NRC sets the annual dose limit for the skin (shallow dose
equivalent) and extremities (hands, forearms, feet, ankles) at 500 mSv (50 rem)
per year. This higher limit reflects the lower radiation sensitivity of these tissues
compared to the whole body .
Question 4
The dose limit for a declared pregnant radiation worker during the entire
gestation period is:
A) 0.5 mSv (50 mrem)
B) 5 mSv (500 mrem)
C) 50 mSv (5 rem)
D) 500 mSv (50 rem)
Answer: B
Rationale: The NRC requires that the dose to the embryo/fetus of a declared
pregnant worker not exceed 5 mSv (500 mrem) during the entire gestation period.
,This is significantly lower than the occupational worker limit to protect the
developing fetus from radiation effects .
Question 5
The annual dose limit for members of the public in unrestricted areas is:
A) 1 mSv (0.1 rem)
B) 5 mSv (0.5 rem)
C) 10 mSv (1 rem)
D) 50 mSv (5 rem)
Answer: A
Rationale: The NRC limits public exposure in unrestricted areas to 1 mSv (0.1 rem)
per year. Additionally, the dose rate in any unrestricted area must not exceed 2
mrem (0.02 mSv) in any one hour .
Question 6
The dose rate limit in an unrestricted area is:
A) 0.1 mrem/hr
B) 2 mrem/hr
C) 5 mrem/hr
D) 10 mrem/hr
Answer: B
Rationale: An unrestricted area is defined as one where a person could not
receive a dose in excess of 2 mrem/hr. Restricted areas are controlled-access
areas for radiation protection purposes .
Question 7
, Which dosimeter type uses thermally stimulated luminescence to record dose?
A) Film badge
B) TLD (Thermoluminescent dosimeter)
C) OSL (Optically stimulated luminescence) badge
D) Geiger-Müller tube
Answer: B
Rationale: TLDs store energy in crystal lattice defects and release light when
heated, with the light output proportional to the absorbed dose. OSL badges use
optically stimulated luminescence (light stimulation rather than heat), while film
badges use photographic film .
Question 8
A radiation worker's whole-body dosimeter reads 3 mSv for the year. Which
statement is true?
A) The worker has exceeded the annual occupational limit
B) The worker is well within the annual limit of 50 mSv
C) The worker must be immediately removed from radiation work
D) The worker has exceeded the public dose limit
Answer: B
Rationale: The annual occupational whole-body dose limit is 50 mSv (5 rem) per
year. A dose of 3 mSv is well below this limit and represents a typical annual dose
for a nuclear medicine technologist. The public dose limit of 1 mSv applies to
members of the general public, not radiation workers .
Question 9
The term "committed effective dose equivalent (CEDE)" refers to:
