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100+ Free ABSNM NMPI Practice Questions

Pass your ABSNM Nuclear Medicine Physics and Instrumentation exam on the first try — instant access, no signup required.

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Which quantum number determines the shape of an electron's orbital?

A
B
C
D
to track
2026 Statistics

Key Facts: ABSNM NMPI Exam

280

Total Questions

180 (Part 1) + 100 (Part 2)

6 hrs

Exam Time

3.5h + 2.5h with lunch break

$1,000+

Exam Fee

ABSNM 2026 fee schedule

NRC

RSO Recognition

10 CFR 35.50

4 yrs

Certification Cycle

100 CE hours for MOC

1x/yr

Exam Frequency

In-person, single date

The ABSNM NMPI exam is a two-part, paper-based exam: Part 1 (180 general questions, 3.5h) + Part 2 (100 specialty questions, 2.5h). Fee: $1,000-$1,030. Administered in-person once per year (May 23, 2026 in Raleigh-Durham, NC). Requires master's/doctorate in physics + 2-3 years medical physics experience. NRC-recognized under 10 CFR 35.50. 4-year certification with 100 CE hours for MOC.

Sample ABSNM NMPI Practice Questions

Try these sample questions to test your ABSNM NMPI exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which quantum number determines the shape of an electron's orbital?
A.Principal quantum number (n)
B.Angular momentum quantum number (l)
C.Magnetic quantum number (ml)
D.Spin quantum number (ms)
Explanation: The angular momentum quantum number (l) determines the shape of the electron orbital (s, p, d, f). The principal quantum number (n) defines the energy level, the magnetic quantum number (ml) defines the spatial orientation, and the spin quantum number (ms) describes the intrinsic spin of the electron.
2What is the primary mode of decay for Tc-99m?
A.Beta-minus emission
B.Isomeric transition (gamma emission)
C.Electron capture
D.Alpha decay
Explanation: Tc-99m decays by isomeric transition, emitting a 140 keV gamma ray as it transitions from the metastable excited state to the ground state of Tc-99. This mono-energetic gamma emission is ideal for imaging with the gamma camera. Tc-99m does not undergo beta-minus, electron capture, or alpha decay.
3A radionuclide has a half-life of 6 hours. What fraction of the original activity remains after 18 hours?
A.1/4
B.1/8
C.1/16
D.1/6
Explanation: After 18 hours, 3 half-lives have elapsed (18/6 = 3). The remaining fraction is (1/2)^3 = 1/8. Each half-life reduces the activity by half, so after one half-life 1/2 remains, after two 1/4, and after three 1/8 of the original activity.
4In secular equilibrium between Mo-99 and Tc-99m, which statement is true?
A.The daughter activity equals the parent activity
B.The daughter activity exceeds the parent activity
C.The parent activity exceeds the daughter activity
D.Both activities decay with the daughter's half-life
Explanation: In secular equilibrium, the parent half-life is much greater than the daughter half-life (Mo-99 t1/2 = 66 h vs Tc-99m t1/2 = 6 h). Once equilibrium is reached, the daughter activity equals the parent activity and both decay with the parent's half-life. This is the principle underlying the Mo-99/Tc-99m generator system.
5Which interaction of gamma rays with matter is most important for photopeak detection in a NaI(Tl) scintillation detector at 140 keV?
A.Compton scattering
B.Photoelectric absorption
C.Pair production
D.Coherent (Rayleigh) scattering
Explanation: At 140 keV in the high-Z NaI(Tl) crystal (effective Z ~ 50), photoelectric absorption dominates. This interaction deposits the full energy of the gamma ray in the crystal, producing the photopeak. Compton scattering deposits only partial energy. Pair production requires photon energies above 1.022 MeV, and coherent scattering does not transfer energy to the detector.
6What is the function of the photomultiplier tube (PMT) in a gamma camera?
A.To collimate incoming gamma rays
B.To convert scintillation light photons into an amplified electrical signal
C.To digitize the analog signal for image reconstruction
D.To discriminate between primary and scattered photons
Explanation: The PMT converts visible light photons from the NaI(Tl) crystal into electrons at the photocathode and amplifies the signal through a series of dynodes, producing a measurable electrical pulse. The collimator defines the geometric field of view, the ADC digitizes the signal, and the pulse height analyzer discriminates energy.
7A dose calibrator is used to measure the activity of a radiopharmaceutical. What type of detector is used in a dose calibrator?
A.NaI(Tl) scintillation detector
B.Pressurized argon ionization chamber
C.Geiger-Mueller tube
D.Cadmium zinc telluride (CZT) semiconductor detector
Explanation: A dose calibrator is a well-type pressurized argon ionization chamber that measures the ionization current produced by gamma rays from the radiopharmaceutical vial. It provides a direct reading of activity in units of mCi or MBq. NaI(Tl) is used in gamma cameras and well counters, GM tubes are used for contamination surveys, and CZT detectors are used in some newer cardiac SPECT cameras.
8The energy resolution of a NaI(Tl) detector for Tc-99m (140 keV) is typically:
A.1-2%
B.5-6%
C.9-10%
D.15-20%
Explanation: The energy resolution of a NaI(Tl) detector is approximately 9-10% at 140 keV, expressed as the full width at half maximum (FWHM) of the photopeak divided by the photopeak energy times 100%. This relatively poor energy resolution (compared to semiconductor detectors at ~5%) makes it more difficult to reject scattered photons but is adequate for clinical imaging with appropriate energy windows.
9What is the purpose of a pulse height analyzer (PHA) in a gamma camera system?
A.To amplify the signal from the photomultiplier tube
B.To select only those pulses within a specified energy window
C.To determine the spatial coordinates of each scintillation event
D.To correct for detector non-uniformity
Explanation: The PHA selects pulses whose amplitudes fall within a preset energy window centered on the photopeak of the radionuclide being imaged. For Tc-99m, a typical window is 15-20% centered at 140 keV. This rejects scattered photons (lower energy) and improves image contrast. Signal amplification is done by the PMT, position logic circuits determine spatial coordinates, and uniformity correction is a separate processing step.
10In counting statistics, if 10,000 counts are collected, what is the standard deviation and percent standard deviation?
A.50 counts, 0.5%
B.100 counts, 1%
C.100 counts, 10%
D.1000 counts, 10%
Explanation: For a Poisson distribution (radioactive decay counting), the standard deviation equals the square root of the total counts: sqrt(10,000) = 100 counts. The percent standard deviation is (100/10,000) x 100% = 1%. This demonstrates that collecting more counts improves counting precision.

About the ABSNM NMPI Exam

The ABSNM NMPI certification designates Diplomates (DABSNM) in nuclear medicine physics. The two-part exam covers general nuclear medicine science (Part 1: 180 questions, 3.5h) and nuclear medicine physics specialty topics (Part 2: 100 questions, 2.5h). Topics include atomic/nuclear physics, radiation detection and measurement, gamma camera and SPECT/PET imaging, quality control, internal dosimetry (MIRD), and radiopharmaceutical science. ABSNM certification is NRC-recognized under 10 CFR 35.50 for RSO eligibility.

Questions

280 scored questions

Time Limit

6 hours (Part 1: 3.5h, Part 2: 2.5h)

Passing Score

Criterion-referenced (not publicly disclosed)

Exam Fee

$1,000–$1,030 (ABSNM)

ABSNM NMPI Exam Content Outline

~35%

Nuclear Physics & Radioactivity

Atomic structure, decay modes, half-life, secular/transient equilibrium, binding energy, nuclear reactions

~25%

Imaging Physics (Planar/SPECT/PET)

Gamma camera, collimators, SPECT reconstruction, attenuation correction, PET coincidence detection, time-of-flight

~20%

Radiation Detection & Measurement

Gas-filled/scintillation/semiconductor detectors, dose calibrators, counting statistics, dead time, energy resolution

~10%

Quality Control

Gamma camera QA, uniformity, spatial resolution, COR, dose calibrator QC, PET scanner QA

~10%

Dosimetry & Radiopharmaceutical Science

MIRD schema, Tc-99m generator, radiochemical purity, dose calculations, NRC regulations

How to Pass the ABSNM NMPI Exam

What You Need to Know

  • Passing score: Criterion-referenced (not publicly disclosed)
  • Exam length: 280 questions
  • Time limit: 6 hours (Part 1: 3.5h, Part 2: 2.5h)
  • Exam fee: $1,000–$1,030

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

ABSNM NMPI Study Tips from Top Performers

1Master radioactive decay equations, half-life calculations, and secular vs transient equilibrium — fundamental to both exam parts
2Know gamma camera physics: collimator types (parallel-hole, pinhole, converging, diverging), uniformity correction, and energy windows
3Understand SPECT reconstruction: FBP vs iterative (OSEM), attenuation correction methods, and center-of-rotation correction
4Study PET physics: coincidence detection, time-of-flight benefit, LSO vs BGO crystal properties, and random/scatter corrections
5Practice counting statistics: chi-square test, standard deviation of counts, propagation of error, minimum detectable activity

Frequently Asked Questions

What is the ABSNM NMPI exam format?

Two-part exam on one day: Part 1 is 180 general questions in 3.5 hours, Part 2 is 100 NMPI specialty questions in 2.5 hours. Paper-based (Scantron) with a provided TI-30XS calculator.

How much does the ABSNM exam cost?

$1,000 by check or $1,030 by credit card. Repeating candidates: $600/$620. The ABSNM Syllabus ($54 value) is included.

Does ABSNM certification qualify me as an RSO?

Yes. ABSNM certification is NRC-recognized under 10 CFR 35.50, which provides a pathway to serve as a Radiation Safety Officer with relevant experience.

When is the 2026 exam?

May 23, 2026 in Raleigh-Durham, North Carolina. The exam is offered once per year, in person only. Application deadline was March 1, 2026.