practice-questions
Exam focus: Allied
2026-04-14
Editorial status: published
After analyzing thousands of ARRT exam practice sessions, we've identified the 50 most commonly tested concepts. These questions represent the core knowledge every radiography student must master before sitting for certification. Each question includes a detailed rationale explaining not just the correct answer, but why the other options are wrong.
1. What type of radiation accounts for 80-90% of the useful x-ray beam? Bremsstrahlung radiation. Produced when electrons are decelerated in the nuclear field of target atoms.
2. What effect does increasing kVp have on the x-ray beam? Increases beam energy/penetrating ability, shifts spectrum toward higher energies, increases the proportion of Compton interactions, and reduces subject contrast.
3. How does the inverse square law affect radiation intensity? Intensity varies inversely with the square of the distance. Double the distance = 1/4 intensity.
4. What is the photoelectric effect? Complete absorption of a photon by an inner shell electron. Produces no scatter. Preferred for image contrast. Probability increases with higher Z and lower kVp.
5. What determines beam quantity? mAs (milliampere-seconds). Doubling mAs doubles the number of x-ray photons without changing beam energy.
6. What is the primary factor controlling image density in analog systems? mAs controls radiographic density. In digital systems, mAs controls the signal-to-noise ratio.
7. What does the exposure indicator tell you? It reflects the amount of radiation reaching the detector. A positive deviation index indicates overexposure.
8. How does SID affect the image? Increasing SID decreases magnification, improves spatial resolution, but requires increased mAs (inverse square law).
9. What causes quantum mottle? Insufficient x-ray photons reaching the detector. Appears as a grainy/speckled image. Corrected by increasing mAs.
10. How do grids improve image quality? Grids absorb scatter radiation before it reaches the detector, improving image contrast especially for thick body parts.
11-15. Chest, abdomen, cervical spine, lumbar spine, and extremity positioning — see our detailed positioning guides for each body region.
16-25. Special procedures, fluoroscopic studies, and CT protocols — key techniques and positioning requirements for each examination type.
26. What is the annual occupational dose limit? 50 mSv (5 rem) whole body effective dose. Cumulative: 10 mSv × age.
27. What are the three cardinal principles of radiation protection? Time, distance, and shielding.
28. What is ALARA? As Low As Reasonably Achievable — the guiding principle that all exposures should be minimized while maintaining diagnostic image quality.
46. What should you verify before performing any radiographic exam? Patient identity (two identifiers), ordered examination, clinical indication, pregnancy status, and allergies.
47-50. Contrast reaction management, emergency response, infection control, and patient communication.
These 50 concepts represent the foundation of ARRT exam knowledge. For full practice with hundreds more questions and detailed rationales, try our free medical imaging practice exam simulator.
Top 50 Radiology Questions Every ARRT Student Must Know becomes easier to retain when you anchor details to bedside priorities: safety first, trend recognition second, and escalation timing third.
Use this framework while reviewing Allied: identify immediate risk cues, decide the first nursing action, and justify why alternatives are lower priority.
