TEXAS NUCLEAR MEDICINE TECHNOLOGIST
LICENSE EXAM PRACTICE QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES 2026 Q&A | INSTANT
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1. Which radionuclide is most commonly used for routine bone
scans?
A. Tl-201
B. Ga-67
C. Tc-99m MDP
D. I-123
Rationale: Tc-99m MDP localizes in areas of osteoblastic
activity, making it ideal for bone scintigraphy.
2. The physical half-life of Tc-99m is:
A. 12 hours
B. 3 hours
C. 6 hours
D. 24 hours
Rationale: Tc-99m has a 6-hour physical half-life, suitable for
imaging and patient safety.
,3. The primary gamma energy of Tc-99m is:
A. 80 keV
B. 140 keV
C. 364 keV
D. 511 keV
Rationale: Tc-99m emits a 140-keV photon ideal for gamma
camera imaging.
4. PET imaging typically uses which photon energy?
A. 140 keV
B. 364 keV
C. 200 keV
D. 511 keV
Rationale: PET utilizes annihilation photons produced at 511
keV.
5. Which organ is the critical organ for I-131 sodium iodide
therapy?
A. Liver
B. Thyroid
C. Bladder
D. Spleen
Rationale: The thyroid concentrates iodine, leading to the
highest radiation dose.
6. What is the primary purpose of a collimator?
A. Increase count rate
,B. Control direction of photons
C. Improve energy resolution
D. Reduce scatter
Rationale: Collimators restrict photon direction to form a
usable image.
7. The acronym ALARA stands for:
A. As Low As Radiation Allowed
B. As Low As Reasonably Achievable
C. As Long As Radiation Acceptable
D. All Regulations Always Reduced
Rationale: ALARA guides radiation dose minimization in
practice.
8. A SPECT scan improves image quality by providing:
A. Faster acquisition
B. True 3-D reconstruction
C. Lower radiation dose
D. No attenuation
Rationale: SPECT collects multiple planar views for 3D
reconstruction.
9. A dose calibrator measures:
A. Energy
B. Geometry
C. Radioactivity
D. Spatial distortion
, Rationale: Dose calibrators measure activity in becquerels or
curies.
10. Which radiopharmaceutical is used for lung perfusion
imaging?
A. Tc-99m DTPA
B. Tc-99m MAA
C. Tc-99m RBCs
D. Tc-99m HMPAO
Rationale: MAA particles lodge in pulmonary capillaries for
perfusion mapping.
11. The recommended needle gauge for radiopharmaceutical IV
injection is:
A. 14-16
B. 18-20
C. 21-25
D. 30
Rationale: 21–25 gauges balance flow and patient comfort.
12. Excessive free pertechnetate in a thyroid scan appears as
uptake in the:
A. Liver
B. Stomach and salivary glands
C. Kidneys only
D. Bone
LICENSE EXAM PRACTICE QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES 2026 Q&A | INSTANT
DOWNLOAD PDF
1. Which radionuclide is most commonly used for routine bone
scans?
A. Tl-201
B. Ga-67
C. Tc-99m MDP
D. I-123
Rationale: Tc-99m MDP localizes in areas of osteoblastic
activity, making it ideal for bone scintigraphy.
2. The physical half-life of Tc-99m is:
A. 12 hours
B. 3 hours
C. 6 hours
D. 24 hours
Rationale: Tc-99m has a 6-hour physical half-life, suitable for
imaging and patient safety.
,3. The primary gamma energy of Tc-99m is:
A. 80 keV
B. 140 keV
C. 364 keV
D. 511 keV
Rationale: Tc-99m emits a 140-keV photon ideal for gamma
camera imaging.
4. PET imaging typically uses which photon energy?
A. 140 keV
B. 364 keV
C. 200 keV
D. 511 keV
Rationale: PET utilizes annihilation photons produced at 511
keV.
5. Which organ is the critical organ for I-131 sodium iodide
therapy?
A. Liver
B. Thyroid
C. Bladder
D. Spleen
Rationale: The thyroid concentrates iodine, leading to the
highest radiation dose.
6. What is the primary purpose of a collimator?
A. Increase count rate
,B. Control direction of photons
C. Improve energy resolution
D. Reduce scatter
Rationale: Collimators restrict photon direction to form a
usable image.
7. The acronym ALARA stands for:
A. As Low As Radiation Allowed
B. As Low As Reasonably Achievable
C. As Long As Radiation Acceptable
D. All Regulations Always Reduced
Rationale: ALARA guides radiation dose minimization in
practice.
8. A SPECT scan improves image quality by providing:
A. Faster acquisition
B. True 3-D reconstruction
C. Lower radiation dose
D. No attenuation
Rationale: SPECT collects multiple planar views for 3D
reconstruction.
9. A dose calibrator measures:
A. Energy
B. Geometry
C. Radioactivity
D. Spatial distortion
, Rationale: Dose calibrators measure activity in becquerels or
curies.
10. Which radiopharmaceutical is used for lung perfusion
imaging?
A. Tc-99m DTPA
B. Tc-99m MAA
C. Tc-99m RBCs
D. Tc-99m HMPAO
Rationale: MAA particles lodge in pulmonary capillaries for
perfusion mapping.
11. The recommended needle gauge for radiopharmaceutical IV
injection is:
A. 14-16
B. 18-20
C. 21-25
D. 30
Rationale: 21–25 gauges balance flow and patient comfort.
12. Excessive free pertechnetate in a thyroid scan appears as
uptake in the:
A. Liver
B. Stomach and salivary glands
C. Kidneys only
D. Bone
