The Day-Before-Exam Guide

The 30 pilot questions are mixed in and look identical to scored ones, so if a question feels bizarre or impossible, it may not even count. Answer it, let it go, move on. Your full appointment is about 4 hours 10 minutes (tutorial, NDA, and survey take up the rest).

Where the points are (scored questions)

Procedures + Image Production = over half the exam. Positioning and technique-factor questions are where prepared people win.

• No new material tonight. Cramming new content the night before trades sleep (which you need) for facts you won't retain. Review this sheet, then close the books.
• Pack now, not tomorrow: two valid, unexpired forms of ID. Your primary must be government-issued with your photo and signature, the second must be signed as well, and the names must match your ARRT record exactly.
• Plan the drive. Know the route and parking. Arrive at least 30 minutes early. Arriving 15+ minutes late can forfeit your appointment.
• Sleep beats studying. A rested brain retrieves; a fried one freezes. Aim for a full night.
• Morning: eat something real, skim this sheet once, and stop. Confidence is a skill. Act like someone who's about to pass, because you are.
• At the center: lockers are provided for personal items; you'll get an erasable noteboard. First thing after you're allowed to write, brain-dump your formulas onto the noteboard. Then they're free for the rest of the exam.

At the test center

• Everything goes in the locker. Phone, smartwatch, calculator, study guides, jacket/hoodie. Empty your pockets too. Nothing personal comes into the exam room, so don't plan to reference anything.
• Check-in photographs you and your ID. Smartwatches and jewelry or hairclips wider than ¼ inch aren't allowed. Leave them at home.
• 18-minute tutorial, then a 2-minute window to accept the NDA. Miss that window and you forfeit the attempt. Accept promptly, and don't write on your noteboard until after you do.
• Breaks are allowed, but the clock keeps running. Leaving for more than 10 minutes triggers an incident report. Use the restroom before you start.
• Noteboard & marker only: no scratch paper and no calculator, so do every calculation on the board. Raise your hand for a fresh one if you fill it.
• Answer every question. There's no penalty for guessing and an unanswered item is scored wrong; you need a scaled 75 to pass.
• Dress in layers for unpredictable room temperature. Any ADA accommodation (earplugs, extra time) must be pre-approved by ARRT with your application. The center can't grant it on the spot.

RADAR: the method for every question

Pacing & strategy rules

• You have ~1 minute per question. Most take 30 seconds; that banks time for the hard ones. Check the on-screen timer at question 60, 115, and 170.
• Never leave a question unanswered. There's no penalty for guessing. Your score is purely the number correct. If unsure: guess, flag it, and return at the end.
• Don't change answers without a concrete reason. "It felt wrong on review" is not a reason. "I misread 'except'" is.
• Two-pass elimination on hard questions: kill the two options you know are wrong, then pick between the remaining two using the concept. A coin flip you've weighted to ~50%+ beats a blank stare at four options.
• Read "EXCEPT / NOT / LEAST" twice. Half the "trick" questions on this exam are just a missed qualifier.
• A weird question ≠ you're failing. It may be one of the 30 pilots. Answer and move on. Momentum is worth more than certainty.

The formulas and the memorize-cold numbers each live on their own one-page sheet now, short enough to write out on the noteboard in your first 15 minutes. Tonight, print them or open them once more:

Patient-care vitals (adult norms)

Decode the projection name: free points

The projection name tells you the beam path: first word = where the beam ENTERS, second word = where it EXITS (the IR side).

• Mediolateral = enters medial, exits lateral → the lateral surface is against the IR (the routine lateral ankle and lateral calcaneus are mediolateral; the axial calcaneus is plantodorsal).
• AP = posterior surface against IR. PA = anterior surface against IR (palm down for the hand/wrist).
• If a question names a projection you've never heard of, decode it. It's an easy question in a disguise.

The oblique rules (the #1 trap zone)

Classic CR angles

• Stochastic effects: probability rises with dose, no threshold, severity independent of dose: cancer and genetic effects. This is what radiation protection (ALARA) is built around.
• Deterministic effects: threshold exists, severity increases with dose: skin erythema, epilation, cataracts, and fetal malformation & growth effects. (Childhood cancer from prenatal exposure, by contrast, is stochastic, with no threshold.)
• Most radiosensitive cells: lymphocytes. Law of Bergonié & Tribondeau: sensitivity is highest in cells that are immature, undifferentiated, and rapidly dividing.
• Most radiosensitive cell-cycle phase: mitosis (M); most resistant: late S.
• Indirect effect dominates with diagnostic x-rays: the photon ionizes water (radiolysis), creating free radicals that then damage DNA. Direct action (photon hits DNA itself) is the minority pathway at diagnostic energies.
• Whole-body lethality: the human LD_50/60 ≈ 3.5 Gy (350 rad): the dose killing half of those exposed within 60 days without medical support.
• Three cardinal principles of protection: time, distance, shielding. Distance is the most powerful (inverse square law).

• Absolutes are usually wrong. "Always," "never," "all," "none," "only": one exception kills them, and medicine rarely deals in absolutes.
• Two opposite options → one is usually the answer. When two choices are direct opposites (AP vs. PA, increase vs. decrease, cephalad vs. caudad), the test is making you choose between them. Spend your focus there.
• The longest, most-qualified answer is often correct: the right choice frequently needs the extra clause to be fully true. A tiebreaker, not a law.
• A number that's an order of magnitude off is a giveaway. If three options cluster and one is wildly larger or smaller, it's usually the trap, not the answer.
• Grammar that doesn't fit the stem (a/an, singular/plural) quietly rules an option out.

Someone will offer to tell you what was on their test. Turn it down, for two separate reasons.

• It describes their exam, not yours. What anyone remembers afterward is a handful of items, reconstructed from a stressful morning. Rebuilding tonight around "mine was loaded with grids" means betting your last hours on one person's partial memory of a different sitting.
• It is a conduct issue, and it reaches both people. ARRT's Rules of Ethics count disclosing exam content, repeating questions or answers in wording close to the real thing, as subverting the examination process. The rule reaches content someone picked up by talking to an examinee, so being on the listening end puts you inside it rather than safely outside it.