ARRT Cheat Sheet 2026

The 30 highest-yield ARRT facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Why should metformin be held after contrast media administration in patients with diabetes? → Risk of lactic acidosis if renal function is impaired
2. What is the recommended minimum waiting period after a severe contrast reaction before re-administering contrast, if clinically necessary? → No standard waiting period — premedication protocol is the key precaution
3. In a lateral projection of the paranasal sinuses, the central ray should be directed to a point: → Midway between the outer canthus and the EAM.
4. Nephrogenic systemic fibrosis (NSF) is a rare complication associated with which contrast agent in patients with severe renal failure? → Gadolinium-based contrast
5. During a barium swallow examination, which position best demonstrates a posterior esophageal impression or defect? → RAO projection
6. How does increasing kVp affect the scatter radiation reaching the image receptor? → Increases scatter production, reducing image contrast
7. In digital radiography, which exposure indicator value signifies optimal exposure on most current CR/DR systems? → EI of 300 (system-dependent target near 300)
8. An AP oblique projection of the shoulder (Grashey method) is performed primarily to demonstrate which of the following? → An open glenohumeral joint space.
9. A patient is positioned for an AP axial projection of the sacrum. Which of the following describes the correct central ray (CR) orientation and centering point? → 15 degrees cephalad, centered 2 inches superior to the pubic symphysis
10. When a patient arrives for a radiologic evaluation, an intravenous contrast injection is necessary. What is the creatinine normal range? → 0.6–1.5 mg per 100 milliliters
11. What is the most common mild adverse reaction to iodinated contrast media? → Nausea and vomiting
12. What does spatial resolution in a digital image system refer to? → The ability to resolve small, closely spaced objects as separate structures
13. In computed radiography (CR), what is the primary function of the photostimulable phosphor (PSP) within the imaging plate? → To absorb the remnant beam energy and store it as a latent image.
14. What does a deviation index (DI) of 0 indicate in a digital imaging system? → Exposure is exactly at the target exposure index
15. What is extravasation in the context of contrast media administration? → Leakage of contrast into surrounding tissue at the injection site
16. The guiding philosophy of radiation protection, which states that all exposures should be kept as low as reasonably achievable, is known by which acronym? → ALARA
17. Which type of contrast agent is routinely used for a double-contrast barium enema? → Low-density barium sulfate with air
18. What is the primary purpose of obtaining a scout (KUB) radiograph before administering contrast for a fluoroscopic GI study? → To assess existing pathology, bowel preparation adequacy, and set technique factors
19. What prevents the helpful x-ray beams from exposing people to unwanted radiation when imaging certain bodily parts? → Collimation
20. What are the post-examination instructions for patients receiving a barium enema? → Consume a lot of liquids.
21. At one meter's distance from the X-ray source, leakage radiation cannot be greater than _________. → 100 mR/hr
22. A patient reports a prior contrast reaction described as 'hives and itching.' How is this reaction classified? → Mild allergic-like reaction
23. Before administering iodinated contrast media, which lab value is most critical to assess renal function? → Serum creatinine / eGFR
24. When evaluating an AP pelvis radiograph for proper positioning, which of the following indicates the patient was not rotated? → The iliac alae and obturator foramina are symmetric.
25. What is the 15% rule in radiographic technique adjustment? → Increasing kVp by 15% has the same effect on exposure as doubling mAs
26. During an upper GI double-contrast examination, what is the primary advantage of the double-contrast technique over single-contrast? → It provides superior mucosal detail enabling detection of small lesions
27. Which of the following is a key characteristic of the photoelectric effect in diagnostic imaging? → It results in total absorption of the incident x-ray photon.
28. A scoliosis series including AP right and left bending projections (Ferguson method) is ordered. What is the primary purpose of performing these bending views? → To differentiate between structural and functional scoliosis
29. A three-way acute abdomen series is ordered on an ambulatory patient. Which of the following combinations of projections is typically included in this series? → AP supine, AP upright, and PA chest
30. When changing from an 8:1 ratio grid to a 12:1 ratio grid for a particular examination, which of the following consequences should the technologist anticipate? → An increase in image contrast.