Free MHP Practice Questions

Question 1

During fluoroscopically guided embolization for ongoing pelvic hemorrhage, cumulative reference air kerma (Ka,r) reaches 6.2 Gy. Equipment performance is normal, and the operator judges that completing the embolization remains necessary to control bleeding. The physicist is asked whether the dose display requires termination. What advice is appropriate?

Accepted Answer

Continue clinically necessary treatment with dose optimization, then arrange dose assessment and appropriate follow-up.

Answer

Terminate irradiation at once because 5 Gy is an upper limit that cannot be exceeded during one procedure.

Answer

Continue without additional dose-management measures because only a measured peak skin dose can trigger follow-up.

Answer

Treat the displayed 6.2 Gy as the peak skin dose and diagnose a radiation skin injury before continuing.

Question 2

A radionuclide calibrator passes its fixed-source constancy check and a vial-based linearity test over the clinical activity range. A Tc-99m solution reads 12% lower after quantitative transfer from a vial to a syringe; the expected reading returns when the solution is transferred back. Decay correction and residual activity have been accounted for. Which explanation best fits this reversible pattern?

Accepted Answer

Container-dependent measurement geometry has not been adequately characterized.

Answer

Ion recombination causes a nonlinear response at the activity being measured.

Answer

The half-life used for decay correction is producing an accumulating timing error.

Answer

Electrometer drift has changed the response to every source measured that day.

Question 3

An adult has received 3.7 GBq of I-131 sodium iodide at an NRC-licensed facility. A documented assessment using realistic contact patterns and all relevant exposure pathways estimates a maximum total effective dose equivalent of 3.2 mSv to any other individual after release. The patient can follow the proposed restrictions. Under 10 CFR 35.75, which disposition is supported?

Accepted Answer

Release with individualized ALARA instructions, including written instructions for the patient.

Answer

Keep the patient hospitalized until each contact's projected dose is below 1 mSv.

Answer

Keep the patient hospitalized because an administered activity above 30 mCi requires inpatient care.

Answer

Release the patient with verbal advice alone because the estimated contact dose is below 5 mSv.

Question 4

A 6 MV treatment vault is being reassessed before a change from conventional delivery to predominantly IMRT. Weekly prescribed dose and primary-beam direction distribution will remain unchanged, but the number of monitor units per delivered gray will increase substantially. Occupancy and beam calibration are unchanged. Which shielding assumption needs revision?

Accepted Answer

Increase leakage workload for the additional monitor units; retain the stated primary-beam dose workload.

Answer

Increase both workloads in proportion to the additional monitor units used per delivered gray.

Answer

Retain both workloads because an unchanged weekly prescribed dose implies unchanged radiation outside the treatment field.

Answer

Apply the primary-beam use factor to the leakage workload to account for the time each wall faces the gantry.

Question 5

At an NRC-licensed hospital, a worker voluntarily declares her pregnancy in writing after the assessed embryo/fetal dose has already reached 4.7 mSv. The radiation safety officer projects an additional 0.35 mSv for the remainder of pregnancy under a monitored work plan without substantial monthly variation. What is the correct regulatory assessment?

Accepted Answer

The plan can comply because this late-declaration provision permits up to 0.5 mSv additional dose.

Answer

The plan cannot comply because the 5 mSv pregnancy limit allows only 0.3 mSv after declaration.

Answer

The plan can comply because a new 5 mSv allowance begins on the date of written declaration.

Answer

The worker must leave all radiation duties because declaration after 4.5 mSv requires complete removal.

Question 6

An Ir-192 HDR afterloader fails to retract its source during treatment. Automatic and remote emergency retraction attempts are unsuccessful, and the room monitor confirms continued irradiation. The authorized user and authorized medical physicist are present, have practiced the unit-specific emergency procedure, and have the designated recovery equipment and a functioning portable survey meter available. Which objective takes priority?

Accepted Answer

End the unintended irradiation by executing the rehearsed source-recovery procedure.

Answer

Reconstruct the delivered dose from the actual source dwell history.

Answer

Preserve controller logs and identify the initiating software fault.

Answer

Keep staff outside the treatment room until the manufacturer's service engineer can attend in person.

Question 7

Particle measurements remain within ISO Class 5 after a nuclear pharmacy adds a lead L-block to its sterile preparation enclosure. During routine manipulations, however, smoke passes over the operator's glove before reaching the exposed vial septum. An alternative layout can preserve the same radiation shielding. Which correction best addresses the demonstrated contamination pathway?

Accepted Answer

Reposition the shielding to restore first-air protection and repeat the dynamic airflow assessment.

Answer

Accept the arrangement because ISO Class 5 particle measurements establish protection of the critical site.

Answer

Increase the room's positive pressure while keeping the shielding and manipulations in their existing positions.

Answer

Retain the layout and increase septum disinfection frequency to compensate for the interrupted airflow.

Question 8

A primary barrier for a 6 MV linac protects a fully occupied office point 6.0 m from the x-ray target. The inner face of the barrier is 3.0 m from the target. Workload is 600 Gy/week at 1 m, the barrier use factor is 0.25, and the design goal is 0.020 mSv/week. For this calculation, assume a numerical photon dose-equivalent conversion of 1 Sv/Gy. Concrete density is 2.35 g/cm³; the first TVL is 37 cm and the equilibrium TVL is 33 cm. Considering only primary radiation, what minimum thickness is required, rounded to the nearest centimeter?

Accepted Answer

180 cm

Answer

176 cm

Answer

197 cm

Answer

199 cm

Question 9

A dose audit finds the same displayed CTDIvol for an abdominal scan of a small child and one of a much larger adolescent. Both values refer to the 32 cm CTDI phantom. Before concluding that the patients received comparable absorbed doses, which step is needed?

Accepted Answer

Estimate SSDE using each patient's size and conversion factors appropriate to the 32 cm reference phantom.

Answer

Accept the comparison because CTDIvol already incorporates each patient's body dimensions during acquisition.

Answer

Multiply each CTDIvol by scan length and use the resulting DLP as that patient's mean organ absorbed dose.

Answer

Compare CTDIvol with adult protocol values because use of the 32 cm phantom removes the need for size correction.

Question 10

After an HDR source exchange, the treatment-planning system and a separate treatment-time checker agree within 0.5%. Both programs import source strength and its reference date from the same oncology information system record. An audit finds that this record still describes the previous source. Which check would have directly broken this common-input failure before treatment?

Accepted Answer

Verify the replacement source strength by independent measurement and reconcile its reference date and recorded value.

Answer

Tighten the agreement criterion between the two calculation programs and reject plans that exceed the smaller tolerance.

Answer

Require two staff members to sign the agreement report produced from the shared source record before treatment.

Answer

Recalculate source decay in both programs using the same stored strength and date immediately before each fraction.

Free MHP Practice Questions

Domain 1: Instrumentation 10% of exam

Question 1

Domain 2: Laboratory Design 5% of exam

Question 2

Domain 3: Standards and Regulations 15% of exam

Question 3

Domain 4: Structural Shielding 15% of exam

Question 4

Question 5

Domain 5: Radiation Oncology 15% of exam

Question 6

Question 7

Domain 6: Diagnostic Imaging 15% of exam

Question 8

Question 9

Domain 7: Nuclear Medicine (molecular imaging) 15% of exam

Question 10

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