Nuclear Medicine – NMTCB Practice Exam 2025/2026
This study guide covers the five major NMTCB content domains: Radiation Physics and
Detection, Radiation Safety and Regulations, Pharmaceutical and Radiopharmaceutical Agents,
Instrumentation Operation and Quality Control, and Clinical Procedures. Candidates will review
radionuclide characteristics, radiopharmacy calculations, imaging instrumentation, quality
assurance procedures, SPECT/PET imaging principles, patient care, and diagnostic nuclear
medicine protocols commonly encountered in clinical practice. The material is designed to
strengthen technical knowledge, reinforce clinical decision-making skills, and support
comprehensive preparation for the Certified Nuclear Medicine Technologist (CNMT)
certification examination
Nuclear Medicine – NMTCB Practice Exam 2025/2026
Radiopharmaceuticals, Radiation Safety, SPECT Imaging –
Radiology Course
Question 1
The most commonly used radionuclide in diagnostic nuclear medicine is:
A) Iodine-131
B) Technetium-99m
C) Thallium-201
D) Gallium-67
Answer: B) Technetium-99m
Rationale: Technetium-99m is the most commonly used radionuclide due to its ideal
physical characteristics: 6-hour half-life, 140 keV gamma emission (ideal for gamma
cameras), and availability from molybdenum-99 generators. It is used in over 80% of all
nuclear medicine procedures.
,Question 2
The half-life of Technetium-99m is approximately:
A) 6 hours
B) 12 hours
C) 24 hours
D) 3 days
Answer: A) 6 hours
Rationale: Technetium-99m has a physical half-life of approximately 6 hours (specifically
6.02 hours). This is ideal for diagnostic imaging as it provides adequate time for
procedures while limiting patient radiation dose.
Question 3
Which of the following is the parent isotope in the Technetium-99m generator?
A) Technetium-99
B) Molybdenum-99
C) Iodine-131
D) Xenon-133
Answer: B) Molybdenum-99
Rationale: The Technetium-99m generator contains Molybdenum-99 as the parent
isotope, which decays to Technetium-99m (the daughter isotope) with a half-life of 66
hours. The generator is commonly called a "moly" generator.
Question 4
The elution process in a Technetium-99m generator uses which solution?
,A) Normal saline (0.9% NaCl)
B) Sterile water
C) Ethanol
D) Heparinized saline
Answer: A) Normal saline (0.9% NaCl)
Rationale: Normal saline is passed through the generator column to elute (wash out) the
Technetium-99m as sodium pertechnetate (NaTcO₄). The process is called milking the
generator.
Question 5
The principle of operation for the Technetium-99m generator is based on:
A) Chromatographic separation
B) Distillation
C) Filtration
D) Centrifugation
Answer: A) Chromatographic separation
Rationale: The generator uses alumina (aluminum oxide) column chromatography.
Molybdenum-99 is adsorbed onto the alumina column, while Technetium-99m is eluted
with saline based on their different chemical properties.
Question 6
Which of the following is NOT a method for assessing eluate purity?
A) Aluminum ion breakthrough test
B) Radionuclide purity test
C) Bacterial endotoxin test
D) Osmolality test
Answer: D) Osmolality test
Rationale: Quality control tests for eluates include aluminum breakthrough, radionuclide
, purity (Mo-99 content), pH, sterility, and bacterial endotoxin tests. Osmolality is not a
standard test.
Question 7
The allowable breakthrough limit for Molybdenum-99 in the eluate is:
A) < 0.15 µCi Mo-99 per mCi of Tc-99m
B) < 1.0 µCi Mo-99 per mCi of Tc-99m
C) < 10 µCi Mo-99 per mCi of Tc-99m
D) < 0.01 µCi Mo-99 per mCi of Tc-99m
Answer: A) < 0.15 µCi Mo-99 per mCi of Tc-99m
Rationale: The acceptable limit for Mo-99 breakthrough in a Tc-99m eluate is less than
0.15 microcuries of Mo-99 per millicurie of Tc-99m at the time of injection, ensuring
patient safety.
Question 8
The gamma energy peak of Technetium-99m is approximately:
A) 80 keV
B) 100 keV
C) 140 keV
D) 364 keV
Answer: C) 140 keV
Rationale: Technetium-99m emits a gamma ray at approximately 140 keV, which is
ideally suited for imaging with gamma cameras and is the primary energy peak for Tc-
99m imaging.
This study guide covers the five major NMTCB content domains: Radiation Physics and
Detection, Radiation Safety and Regulations, Pharmaceutical and Radiopharmaceutical Agents,
Instrumentation Operation and Quality Control, and Clinical Procedures. Candidates will review
radionuclide characteristics, radiopharmacy calculations, imaging instrumentation, quality
assurance procedures, SPECT/PET imaging principles, patient care, and diagnostic nuclear
medicine protocols commonly encountered in clinical practice. The material is designed to
strengthen technical knowledge, reinforce clinical decision-making skills, and support
comprehensive preparation for the Certified Nuclear Medicine Technologist (CNMT)
certification examination
Nuclear Medicine – NMTCB Practice Exam 2025/2026
Radiopharmaceuticals, Radiation Safety, SPECT Imaging –
Radiology Course
Question 1
The most commonly used radionuclide in diagnostic nuclear medicine is:
A) Iodine-131
B) Technetium-99m
C) Thallium-201
D) Gallium-67
Answer: B) Technetium-99m
Rationale: Technetium-99m is the most commonly used radionuclide due to its ideal
physical characteristics: 6-hour half-life, 140 keV gamma emission (ideal for gamma
cameras), and availability from molybdenum-99 generators. It is used in over 80% of all
nuclear medicine procedures.
,Question 2
The half-life of Technetium-99m is approximately:
A) 6 hours
B) 12 hours
C) 24 hours
D) 3 days
Answer: A) 6 hours
Rationale: Technetium-99m has a physical half-life of approximately 6 hours (specifically
6.02 hours). This is ideal for diagnostic imaging as it provides adequate time for
procedures while limiting patient radiation dose.
Question 3
Which of the following is the parent isotope in the Technetium-99m generator?
A) Technetium-99
B) Molybdenum-99
C) Iodine-131
D) Xenon-133
Answer: B) Molybdenum-99
Rationale: The Technetium-99m generator contains Molybdenum-99 as the parent
isotope, which decays to Technetium-99m (the daughter isotope) with a half-life of 66
hours. The generator is commonly called a "moly" generator.
Question 4
The elution process in a Technetium-99m generator uses which solution?
,A) Normal saline (0.9% NaCl)
B) Sterile water
C) Ethanol
D) Heparinized saline
Answer: A) Normal saline (0.9% NaCl)
Rationale: Normal saline is passed through the generator column to elute (wash out) the
Technetium-99m as sodium pertechnetate (NaTcO₄). The process is called milking the
generator.
Question 5
The principle of operation for the Technetium-99m generator is based on:
A) Chromatographic separation
B) Distillation
C) Filtration
D) Centrifugation
Answer: A) Chromatographic separation
Rationale: The generator uses alumina (aluminum oxide) column chromatography.
Molybdenum-99 is adsorbed onto the alumina column, while Technetium-99m is eluted
with saline based on their different chemical properties.
Question 6
Which of the following is NOT a method for assessing eluate purity?
A) Aluminum ion breakthrough test
B) Radionuclide purity test
C) Bacterial endotoxin test
D) Osmolality test
Answer: D) Osmolality test
Rationale: Quality control tests for eluates include aluminum breakthrough, radionuclide
, purity (Mo-99 content), pH, sterility, and bacterial endotoxin tests. Osmolality is not a
standard test.
Question 7
The allowable breakthrough limit for Molybdenum-99 in the eluate is:
A) < 0.15 µCi Mo-99 per mCi of Tc-99m
B) < 1.0 µCi Mo-99 per mCi of Tc-99m
C) < 10 µCi Mo-99 per mCi of Tc-99m
D) < 0.01 µCi Mo-99 per mCi of Tc-99m
Answer: A) < 0.15 µCi Mo-99 per mCi of Tc-99m
Rationale: The acceptable limit for Mo-99 breakthrough in a Tc-99m eluate is less than
0.15 microcuries of Mo-99 per millicurie of Tc-99m at the time of injection, ensuring
patient safety.
Question 8
The gamma energy peak of Technetium-99m is approximately:
A) 80 keV
B) 100 keV
C) 140 keV
D) 364 keV
Answer: C) 140 keV
Rationale: Technetium-99m emits a gamma ray at approximately 140 keV, which is
ideally suited for imaging with gamma cameras and is the primary energy peak for Tc-
99m imaging.
