PRC RadTech common mistakes
PRC RadTech · Understand the traps and how to avoid them.
On kVp/mAs conversion items, the candidate changes the two variables in the same direction (raises kVp and keeps or raises mAs) instead of applying the reciprocal change needed to hold receptor exposure constant.
They memorised the slogan 'kVp up, mAs down' without attaching it to the underlying relationship: a 15% kVp increase roughly doubles receptor exposure, so mAs must be halved to compensate. Under time pressure the slogan loses its direction.
What to do instead
Write the rule as an equation card and drill 15-20 paired items where each stem says which variable changed and asks for the new mAs: +15% kVp means mAs ÷ 2; −15% kVp means mAs × 2. After each answer, verify by asking 'is receptor exposure the same?' before moving on.
Mixes up dose quantities and their units: answers an equivalent-dose or effective-dose question in gray, treats mGy and µGy as interchangeable, or drops the exponent when converting between them.
Absorbed dose, equivalent dose, effective dose and exposure all sound alike and are usually memorised as bare numbers without the unit attached, so the unit dimension never gets checked.
What to do instead
Build a four-row table (quantity → unit → SI → what it measures) and force yourself to write the unit beside every numeric answer; then eliminate any option whose unit is the wrong dimension for what the stem asks, before doing arithmetic.
Computes heat units or checks a tube rating using the single-phase factor for a three-phase or high-frequency generator, or omits the exposure time (seconds) from the calculation.
Heat-unit questions are the only routine multi-step arithmetic in the equipment section; candidates memorise one worked example and transplant its factor and formula to units of a different type.
What to do instead
Keep a one-line formula card (HU = kVp × mA × time × generator factor) plus a factor table by generator type, and practise by reading the stem first for the generator type and the time in seconds before touching the numbers.
Sets the central ray perpendicular to the image receptor on every projection item, ignoring the tube angulation and centring point that the specific projection requires (for example axial views of the coccyx, sacrum, or shoulder outlet views).
Candidates learn positioning as a list of 'patient position + part' and strip off the angulation detail, which is the part of the stem that actually distinguishes the correct answer.
What to do instead
For each region, build a three-column matrix (projection → patient/part position → CR angle and entry point) and rehearse it aloud; in the exam, locate the CR angle phrase in the stem before looking at the options, since many distractors differ only by angle.
Carries a landmark or foraminal orientation rule from one spinal region to another, such as applying the cervical intervertebral foramina rotation to the thoracic spine, or placing the same bony structure anteriorly in two different projections.
Regional anatomy is studied region by region, so each rule is stored with its chapter rather than with a discriminating feature, and the exam deliberately uses the same wording for different regions.
What to do instead
Make a single comparison chart across cervical, thoracic and lumbar for foraminal orientation, CR angle and key landmarks, and sketch each region once from memory; when an item appears, name the region out loud before choosing.
Reads the digital exposure indicator as if it were film optical density: assumes a higher number always means overexposure across all vendors, or ignores the deviation index and answers as though any EI excursion signals a repeat.
The candidate's mental model was built on film-screen density and has not been rebuilt for digital, where the EI scale direction is vendor-specific and the deviation index is the standardised comparison to the target.
What to do instead
Learn the two-layer rule: know the target EI for the department's vendor, know the direction of the scale for that vendor, and use the deviation index to judge magnitude. Practise with items that state the vendor or give a deviation index value and ask for the correct action.
Blames kVp, scatter or grid ratio for a low-contrast image when the stem describes a problem that a window width/level change or a look-up table would fix, and vice versa.
Pre-digital review material collapses all contrast into kVp, so candidates never separate acquisition factors (kVp, scatter, grid, collimation, part thickness) from display factors (window, level, LUT, post-processing).
What to do instead
Before answering any image-quality item, tag the stem as 'acquisition' or 'display'; then only consider options from that list. Build two short lists side by side and test yourself by sorting 20 stems into the two categories without choosing answers first.
Uses the public dose limit for occupational questions, or answers a 'dose limit for a student radiographer / declared pregnant worker / lens' item with a single generic number instead of the limit that applies to that person and averaging period.
Dose limits are memorised as a loose cluster of numbers with no owner attached, and the limits for the lens and for the fetus were revised, so older remembered values compete with the current ones.
What to do instead
Build a limits table with columns for person category, effective dose, lens dose, extremity/skin dose, and the averaging period; add rows for trainees and declared pregnant workers. In the exam, identify the person in the stem first, then read the limit off the row.
Answers scope-of-practice and licensure items from general impression rather than from the Radiologic Technology Act and its implementing rules: who may own or operate X-ray equipment, what the Board versus the Commission does, and which acts are reserved to the licensed technologist.
The legal section feels like trivia, so it gets read once and never tested, leaving only vague impressions such as 'the PRC handles everything' or 'any physician can operate the unit'.
What to do instead
Outline the Act by section headings (title, scope of practice, Board powers, licensing, penalties) and write one sentence per heading in your own words, then practise items that hinge on distinguishing Board functions from Commission functions and on who may legally operate equipment.
Resolves ethics and professional-practice scenarios by picking the option that feels most personally kind or legally safest, rather than the option that matches the code's duties to the patient, to colleagues and to the profession - for example disclosing findings to a relative, or skipping patient identification because the patient is known to them.
Ethics items are treated as 'common sense' and answered quickly, but the distractors are written to be plausible everyday responses, while the keyed answer is the formal duty, often the one that protects confidentiality or patient autonomy even when it seems less helpful.
What to do instead
Adopt a fixed decision rule: identify the primary duty in the stem (beneficence, confidentiality, informed consent, scope of practice, reporting), then choose the option that satisfies that duty and escalates through the proper channel rather than around it. Rehearse with 15 short scenarios and justify each rejection out loud.