ARRT Nuclear Medicine common mistakes
ARRT Nuclear Medicine · Understand the traps and how to avoid them.
Answers procedure questions by matching a radiopharmaceutical name to a memorized scan title, even when the stem describes a different mechanism, such as choosing sulfur colloid for a GI bleed because both were studied together.
Procedure lists are memorized as isolated facts rather than as mechanism-to-indication pairs, and exam stems use clinical wording that does not repeat the scan name.
What to do instead
Build and rehearse a two-column table of radiopharmaceutical and localization mechanism versus clinical indication and typical timing; for every practice stem, state the mechanism before selecting the study.
Uses a fixed standard imaging time for every study instead of adjusting for radiopharmaceutical kinetics and patient factors, such as failing to delay hepatobiliary imaging when the gallbladder is not seen or mistiming a renal scan after diuretic administration.
Protocol times are learned as numbers rather than as consequences of uptake and clearance, while question stems add patient-specific variables.
What to do instead
For each protocol, write the physiologic rationale for the start time and any delayed views, then practice decision rules for when to delay imaging or administer an adjunct.
Selects or prepares a radiopharmaceutical without checking formulation and patient-specific constraints, such as MAA particle number in pulmonary hypertension or pediatric dosing, oxidant levels in pertechnetate, or aluminum breakthrough in generator eluate.
Attention focuses on the isotope name and overlooks formulation limits and quality attributes that are tested in scenario form.
What to do instead
Use a pre-administration checklist covering prescribed activity, particle count and volume, radionuclidic and radiochemical purity, generator eluate limits, and patient-specific contraindications.
Calculates administered or remaining activity without consistent decay correction and unit conversion, such as using calibration-time activity as the injected activity or mixing mCi and MBq in the same equation.
Half-lives are memorized without the exponential decay setup, and time units or activity units create traps.
What to do instead
Write A(t) = A0 times e to the minus 0.693 t over T1/2 with t and T1/2 in the same unit; convert all activities to one unit before calculating and check the result with a rough half-life estimate.
Pairs an isotope with the wrong collimator or energy window out of habit, such as selecting a low-energy collimator for I-131 or a 140-keV window for F-18.
Collimator and window facts are memorized separately from isotope photon energy, but exam items combine them.
What to do instead
Create an isotope card listing principal photon energy, required collimator type, and window setting; practice rejecting options that mismatch energy or septal thickness.
Interprets PET/CT images or SUV values without accounting for attenuation correction, blood glucose, uptake time, or lean-body-mass normalization.
SUV is treated as a fixed tumor marker rather than a semi-quantitative index affected by acquisition and patient variables.
What to do instead
For each PET question, list the assumptions behind SUV and check whether the stem changes glucose, uptake time, reconstruction, or attenuation correction; compare lesions with background rather than relying only on absolute cutoffs.
Applies radiation dose limits to the wrong group or uses inverse-square and shielding formulas without converting units or distinguishing exposure rate from accumulated dose.
Limits, units, and geometry are learned as separate facts, while exam stems combine them in one calculation.
What to do instead
Make a one-page reference of dose limits by category and practice calculations with dimensional analysis, separating mSv, mGy, and mR and separating activity from exposure rate.
Responds to a radioactive spill by decontaminating immediately without first securing the area, surveying, using appropriate PPE, or segregating waste, or uses a dose-rate meter to quantify removable contamination.
Spill response is memorized as a sequence of actions rather than as a survey-and-containment decision tree, and survey instruments are confused.
What to do instead
Rehearse a spill algorithm: warn and secure, survey with the appropriate detector, contain, decontaminate from low to high, re-survey, and document; distinguish survey-meter readings from wipe-test contamination.
Mixes up QC test frequency and acceptance limits, such as daily energy peaking versus weekly uniformity, dose calibrator constancy versus linearity, or when a chi-square test applies.
QC tables are memorized by rows without anchoring each test to its purpose, instrument, and corrective action.
What to do instead
Build a QC matrix by instrument with columns for test, frequency, limit, and action if failed; group tests by purpose such as accuracy, constancy, linearity, geometry, resolution, and sensitivity.
Skips or rushes patient screening and preparation, such as not checking pregnancy or breastfeeding status, renal function, recent contrast, fasting or glucose, or medications that block uptake.
Attention stays on the imaging protocol and treats screening as paperwork, while exam stems hide contraindications in the patient history.
What to do instead
Use a structured pre-scan checklist and practice history-hunt questions by identifying the one medication, laboratory value, or condition that changes timing, dose, or whether to proceed.