Free ABR-NMP-P2 Practice Questions

Question 1

A crescent-shaped cold band crosses the liver dome on attenuation-corrected FDG PET but is absent from the non-attenuation-corrected images. Respiratory misregistration places CT lung over part of the liver's emission volume. Reconstructing the same PET events after correcting this alignment removes the band. What happened in the original reconstruction?

Accepted Answer

CT lung coefficients caused insufficient compensation for attenuation of hepatic coincidences.

Answer

Liver coefficients assigned to lung caused excessive attenuation compensation.

Answer

An overestimated injected activity scaled the entire hepatic uptake distribution downward.

Answer

Respiratory motion blurred hepatic activity out of the band in both PET reconstructions.

Question 2

Before bone imaging, a dual-head gamma camera develops a focal count deficit on an extrinsic flood. Both intrinsic floods are normal. With a verified uniform source, the deficit follows one collimator when that collimator is transferred between heads; inspection confirms bent septa. An undamaged, compatible replacement is available. Choose the appropriate restriction on clinical use.

Accepted Answer

Remove the damaged collimator from service and qualify the replacement with the required QC.

Answer

Suspend both heads pending replacement of their intrinsic uniformity corrections.

Answer

Retain the collimator after acquiring an extrinsic correction map that removes the visible deficit.

Answer

Reserve the damaged collimator for planar examinations, where its defect will not generate tomographic rings.

Question 3

An adult treated with I-131 is clinically ready for discharge from a U.S. NRC-licensed facility. A documented, patient-specific assessment predicts a total effective dose equivalent of 3.2 mSv to the most-exposed other individual, with lower doses to everyone else. The proposed home precautions are feasible, and the patient can follow them. No additional license restriction applies. Under 10 CFR 35.75, which disposition is appropriate?

Accepted Answer

Authorize release with instructions, including written precautions, to keep other individuals' doses as low as reasonably achievable.

Answer

Continue inpatient isolation until the projected dose to every other individual is below 1 mSv.

Answer

Authorize release with verbal advice alone because the projected dose is below the 5-mSv release criterion.

Answer

Require an unrestricted-area hourly dose-rate limit to be met before considering the individualized release assessment.

Question 4

A wipe sample produces a background-subtracted signal of 34 counts. For this validated counting method and measurement configuration, the critical level LC is 23 net counts and the detection limit LD is 49 net counts. The method uses 5% false-positive and false-negative error probabilities. A reviewer marks the result 'not detected' because 34 is below 49. How should that decision be revised?

Accepted Answer

Report detection; LC governs this decision, whereas LD describes the method's detection capability.

Answer

Report no detection because the net signal remains below LD.

Answer

Report a 95% probability that the sample contains activity because the result lies between LC and LD.

Answer

Classify the result as indeterminate until a repeat measurement produces a net signal above LD.

Question 5

Relative stress Rb-82 PET perfusion images appear homogeneous. Absolute stress myocardial blood flow, however, is below the laboratory's validated reference interval in all three coronary territories, while resting flow is within its reference interval. Vasodilator preparation, tracer delivery, dynamic sampling, motion correction, and calibration have been verified. Which conclusion reconciles the relative and quantitative findings?

Accepted Answer

Relative normalization can conceal global impairment of vasodilator flow without identifying its specific vascular cause.

Answer

The homogeneous relative images exclude physiologically important disease, so the absolute flow findings should be disregarded.

Answer

The absence of a regional defect establishes isolated microvascular disease rather than epicardial coronary disease.

Answer

The global stress-flow reduction establishes three-vessel obstructive epicardial coronary disease.

Question 6

For a 72-kg patient injected with F-18 FDG at 09:00, the pre-injection assay is 320 MBq and the post-injection syringe residual is 20 MBq; both assay values have already been corrected to 09:00. There is no extravasation or additional residual. PET begins at 10:50. The image activity concentration, decay-corrected to scan start rather than injection time, is 6.25 kBq/mL in a lesion. Using an F-18 half-life of 110 minutes and conventional body-weight normalization, what SUV should be reported?

Accepted Answer

3.00

Answer

1.50

Answer

2.81

Answer

3.21

Question 7

At the end of an HDR brachytherapy fraction, the console indicates that the Ir-192 source is retracted. The room monitor remains elevated, and a functioning portable survey meter localizes a strong field to the patient's applicator. The prescribed external emergency-retraction attempt does not change the readings. The trained authorized team is present. What takes priority now?

Accepted Answer

Use the rehearsed emergency procedure to separate the patient from the unretracted source.

Answer

Keep the patient immobilized behind the closed treatment-room door until the service engineer arrives.

Answer

Reconstruct the delivered dose before considering an in-room intervention.

Answer

Reset the console and repeat its source-position check before declaring a retraction failure.

Question 8

An I-131 SPECT phantom study using a low-energy collimator shows star-shaped streaks around a hot source. The pattern persists at low count rates and with adequate angular sampling. A narrower window around 364 keV reduces counts but leaves the streaks. Which acquisition change most directly addresses the source of this artifact?

Accepted Answer

Use high-energy collimation with septa appropriate for the I-131 photon emissions.

Answer

Acquire more projection angles to distribute the streak counts across additional views.

Answer

Decrease pixel size to resolve source and penetration counts.

Answer

Narrow the 364-keV window further to reject photons that pass through collimator septa.

Question 9

A well-counter assay records 10,000 gross counts in 100 seconds. A separate, matched blank records 4,000 counts in 200 seconds. Background is stable, the measurements are independent and Poisson-distributed, and decay, dead time, and timing uncertainty are negligible. Which net count rate and one-standard-deviation counting uncertainty belong in the assay result?

Accepted Answer

80.0 ± 1.05 counts/s

Answer

80.0 ± 0.89 counts/s

Answer

80.0 ± 0.95 counts/s

Answer

100.0 ± 1.00 counts/s

Question 10

A PET electronics upgrade improves coincidence timing resolution from 600 ps to 300 ps without changing the crystal dimensions or ring geometry. Matched, high-count point-source tests show essentially unchanged reconstructed spatial FWHM. A reviewer calls the upgrade ineffective because the spatial FWHM did not halve. Select the technically sound response.

Accepted Answer

Better along-line-of-response localization can reduce image noise without halving the point-source FWHM.

Answer

Unchanged spatial FWHM invalidates the measured improvement in timing resolution.

Answer

Finer reconstruction voxels are necessary before improved timing can provide any image-noise advantage.

Answer

The timing improvement is useful only if the accepted coincidence window is narrowed by the same factor.

Free ABR-NMP-P2 Practice Questions

Domain 1: Radiation Protection, Safety, Professionalism and Ethics

Question 1

Question 2

Domain 2: PET & Hybrid

Question 3

Question 4

Question 5

Domain 3: Single photon imaging systems including scintillation cameras, solid state cameras and hybrids

Question 6

Question 7

Domain 4: Radiation measurements including dose calibrators, well counters, survey meters, thyroid probes

Question 8

Question 9

Domain 5: Clinical Procedures

Question 10

That's 10 of 1,030