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NUCLEAR MEDICINE BOARD REVIEW
|PRACTICE QUESTIONS AND ANSWERS |
LATEST UPDATE 2026/2027 | EXAM REVIEW.
TABLE OF CONTENTS
1. Physics, Instrumentation, and Quality Control (25 Questions)
2. Radiopharmacy and Radiopharmaceuticals (20 Questions)
3. Radiation Safety and Regulatory Compliance (15 Questions)
4. Skeletal and Cardiovascular Imaging (15 Questions)
5. Pulmonary, GI, Renal, and Endocrine Imaging (15 Questions)
6. Oncologic, CNS, and Infection Imaging (10 Questions)
, Page |2
SECTION 1: PHYSICS, INSTRUMENTATION, AND QUALITY CONTROL
Question 1: An atomic nucleus contains 39 protons and 50 neutrons. What is its mass
number (A)?
A) 39
B) 50
C) 89
D) 11
Correct Answer: C) 89
The mass number (A) is the sum of protons and neutrons: A = 39 + 50 = 89. The atomic
number (Z) is 39 (protons), and the neutron number (N) is 50.
Question 2: What is the primary physical interaction responsible for image formation in
gamma camera imaging?
A) Compton scattering
B) Photoelectric absorption
C) Pair production
D) Coherent scattering
Correct Answer: B) Photoelectric absorption
Photoelectric absorption is the primary interaction that contributes to image formation in
gamma camera imaging. When a gamma photon undergoes photoelectric absorption in the
scintillation crystal, its entire energy is deposited, producing a light flash that contributes to
the image. Compton scattering events are largely rejected by the pulse height analyzer.
Question 3: What is the primary mode of decay for Technetium-99m?
A) Alpha decay
B) Isomeric transition
C) Beta-minus decay
D) Positron emission
Correct Answer: B) Isomeric transition
Tc-99m decays by isomeric transition, emitting a 140 keV gamma ray and transitioning to the
ground state, Tc-99. This nearly pure gamma emission with an ideal energy is why Tc-99m is
, Page |3
the workhorse of diagnostic nuclear medicine. Its 6-hour half-life is also well suited for
clinical procedures.
Question 4: What is the primary photon energy of Tc-99m used for gamma camera imaging?
A) 140 keV
B) 364 keV
C) 511 keV
D) 159 keV
Correct Answer: A) 140 keV
The primary photon energy of Tc-99m is 140 keV, which is ideal for gamma camera imaging
because it is high enough to penetrate tissue but low enough to be efficiently detected by
sodium iodide crystals. For comparison, I-131 emits 364 keV, and annihilation photons are
511 keV.
Question 5: In PET imaging, what is the energy of each annihilation photon produced when
a positron encounters an electron?
A) 140 keV
B) 364 keV
C) 511 keV
D) 159 keV
Correct Answer: C) 511 keV
When a positron annihilates with an electron, both particles' rest masses are converted into
two 511 keV gamma photons emitted at approximately 180 degrees to each other. This 511
keV energy is characteristic of PET imaging and enables coincidence detection.
Question 6: Which scintillation crystal is most commonly used in gamma cameras?
A) Bismuth germanate (BGO)
B) Sodium iodide activated with thallium (NaI(Tl))
C) Lutetium oxyorthosilicate (LSO)
D) Cesium iodide (CsI)
Correct Answer: B) Sodium iodide activated with thallium (NaI(Tl))
, Page |4
Thallium-activated sodium iodide (NaI(Tl)) is the standard scintillation crystal for gamma
cameras due to its high light output, which provides good energy resolution at the 140 keV
energy of Tc-99m. BGO and LSO are used in PET detectors.
Question 7: Which type of collimator is best suited for imaging a patient with a high body
mass index (BMI)?
A) Low-energy high-resolution (LEHR) collimator
B) Low-energy all-purpose (LEAP) collimator
C) Medium-energy general-purpose (MEGP) collimator
D) High-energy general-purpose (HEGP) collimator
Correct Answer: C) Medium-energy general-purpose (MEGP) collimator
MEGP collimators provide thicker septa and longer holes to reduce septal penetration from
higher-energy photons and scattered radiation, which is more prevalent in larger patients.
LEHR and LEAP collimators are designed for low-energy photons and may allow septal
penetration in obese patients, degrading image quality.
Question 8: The type of scintillation camera collimator that can only magnify the portion of
the anatomy in the image is a:
A) Parallel-hole collimator
B) Diverging collimator
C) Converging collimator
D) Pinhole collimator
Correct Answer: C) Converging collimator
Converging collimators magnify the image, which is useful for imaging small organs in
larger patients. Pinhole collimators also magnify but invert the image. Diverging collimators
minify the image, allowing visualization of larger areas.
Question 9: What is the purpose of the pulse height analyzer in a gamma camera?
A) To focus the gamma rays onto the crystal
B) To reject scattered photons and accept photopeak events
C) To amplify the signal from the photomultiplier tubes
D) To convert light into an electrical signal
NUCLEAR MEDICINE BOARD REVIEW
|PRACTICE QUESTIONS AND ANSWERS |
LATEST UPDATE 2026/2027 | EXAM REVIEW.
TABLE OF CONTENTS
1. Physics, Instrumentation, and Quality Control (25 Questions)
2. Radiopharmacy and Radiopharmaceuticals (20 Questions)
3. Radiation Safety and Regulatory Compliance (15 Questions)
4. Skeletal and Cardiovascular Imaging (15 Questions)
5. Pulmonary, GI, Renal, and Endocrine Imaging (15 Questions)
6. Oncologic, CNS, and Infection Imaging (10 Questions)
, Page |2
SECTION 1: PHYSICS, INSTRUMENTATION, AND QUALITY CONTROL
Question 1: An atomic nucleus contains 39 protons and 50 neutrons. What is its mass
number (A)?
A) 39
B) 50
C) 89
D) 11
Correct Answer: C) 89
The mass number (A) is the sum of protons and neutrons: A = 39 + 50 = 89. The atomic
number (Z) is 39 (protons), and the neutron number (N) is 50.
Question 2: What is the primary physical interaction responsible for image formation in
gamma camera imaging?
A) Compton scattering
B) Photoelectric absorption
C) Pair production
D) Coherent scattering
Correct Answer: B) Photoelectric absorption
Photoelectric absorption is the primary interaction that contributes to image formation in
gamma camera imaging. When a gamma photon undergoes photoelectric absorption in the
scintillation crystal, its entire energy is deposited, producing a light flash that contributes to
the image. Compton scattering events are largely rejected by the pulse height analyzer.
Question 3: What is the primary mode of decay for Technetium-99m?
A) Alpha decay
B) Isomeric transition
C) Beta-minus decay
D) Positron emission
Correct Answer: B) Isomeric transition
Tc-99m decays by isomeric transition, emitting a 140 keV gamma ray and transitioning to the
ground state, Tc-99. This nearly pure gamma emission with an ideal energy is why Tc-99m is
, Page |3
the workhorse of diagnostic nuclear medicine. Its 6-hour half-life is also well suited for
clinical procedures.
Question 4: What is the primary photon energy of Tc-99m used for gamma camera imaging?
A) 140 keV
B) 364 keV
C) 511 keV
D) 159 keV
Correct Answer: A) 140 keV
The primary photon energy of Tc-99m is 140 keV, which is ideal for gamma camera imaging
because it is high enough to penetrate tissue but low enough to be efficiently detected by
sodium iodide crystals. For comparison, I-131 emits 364 keV, and annihilation photons are
511 keV.
Question 5: In PET imaging, what is the energy of each annihilation photon produced when
a positron encounters an electron?
A) 140 keV
B) 364 keV
C) 511 keV
D) 159 keV
Correct Answer: C) 511 keV
When a positron annihilates with an electron, both particles' rest masses are converted into
two 511 keV gamma photons emitted at approximately 180 degrees to each other. This 511
keV energy is characteristic of PET imaging and enables coincidence detection.
Question 6: Which scintillation crystal is most commonly used in gamma cameras?
A) Bismuth germanate (BGO)
B) Sodium iodide activated with thallium (NaI(Tl))
C) Lutetium oxyorthosilicate (LSO)
D) Cesium iodide (CsI)
Correct Answer: B) Sodium iodide activated with thallium (NaI(Tl))
, Page |4
Thallium-activated sodium iodide (NaI(Tl)) is the standard scintillation crystal for gamma
cameras due to its high light output, which provides good energy resolution at the 140 keV
energy of Tc-99m. BGO and LSO are used in PET detectors.
Question 7: Which type of collimator is best suited for imaging a patient with a high body
mass index (BMI)?
A) Low-energy high-resolution (LEHR) collimator
B) Low-energy all-purpose (LEAP) collimator
C) Medium-energy general-purpose (MEGP) collimator
D) High-energy general-purpose (HEGP) collimator
Correct Answer: C) Medium-energy general-purpose (MEGP) collimator
MEGP collimators provide thicker septa and longer holes to reduce septal penetration from
higher-energy photons and scattered radiation, which is more prevalent in larger patients.
LEHR and LEAP collimators are designed for low-energy photons and may allow septal
penetration in obese patients, degrading image quality.
Question 8: The type of scintillation camera collimator that can only magnify the portion of
the anatomy in the image is a:
A) Parallel-hole collimator
B) Diverging collimator
C) Converging collimator
D) Pinhole collimator
Correct Answer: C) Converging collimator
Converging collimators magnify the image, which is useful for imaging small organs in
larger patients. Pinhole collimators also magnify but invert the image. Diverging collimators
minify the image, allowing visualization of larger areas.
Question 9: What is the purpose of the pulse height analyzer in a gamma camera?
A) To focus the gamma rays onto the crystal
B) To reject scattered photons and accept photopeak events
C) To amplify the signal from the photomultiplier tubes
D) To convert light into an electrical signal
