ABR Cheat Sheet 2026

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

1. Which parameter most directly controls spatial resolution in a CT scanner? → Detector aperture and reconstruction kernel
2. Which quality control test on a linear accelerator uses a Winston-Lutz phantom? → Isocenter coincidence between radiation and mechanical isocenters
3. Which of the following is the most effective method to reduce patient dose during fluoroscopic procedures? → Increasing source-to-skin distance
4. What is the primary difference between positron emission tomography (PET) and single-photon emission computed tomography (SPECT)? → PET uses positrons and gamma rays for imaging
5. Which ethical principle is most directly applicable to medical ethics and law? → Beneficence — acting in the patient's best interest
6. What ACR/AAPM quality control test for CT scanners evaluates the system's ability to reproduce a known CT number for water? → CT number accuracy and uniformity test
7. Which QA procedure is specifically designed to test the end-to-end accuracy of a stereotactic radiosurgery (SRS) system? → End-to-End (E2E) test
8. What is the standard of care requirement for diagnostic procedures in clinical practice? → The level of care a reasonably competent practitioner would provide
9. Which ethical principle is most directly applicable to documentation standards? → Beneficence — acting in the patient's best interest
10. What is the primary advantage of a flat-panel detector over an image intensifier in fluoroscopy? → Larger field of view with less geometric distortion and better DQE uniformity
11. How should a practitioner handle an unexpected finding during patient safety protocols procedures? → Document it and follow established protocols for further evaluation
12. According to TG-142, what is the recommended monthly tolerance for beam flatness (non-IMRT) on a linear accelerator? → ±2%
13. What does the term 'penumbra' refer to in radiation therapy beam physics? → The region at the beam edge where dose falls rapidly from high to low values
14. Which AAPM protocol provides dosimetry recommendations for low-energy photon brachytherapy sources such as 125I seeds? → TG-43
15. What is the primary purpose of using lead shielding during radiological procedures? → To prevent unnecessary radiation exposure to healthy tissues
16. Which QA parameter is evaluated during a 'picket fence' test on a linear accelerator? → MLC leaf positioning accuracy
17. How should a practitioner handle an unexpected finding during treatment planning procedures? → Document it and follow established protocols for further evaluation
18. What is the role of bolus material in radiation therapy? → To bring the dose closer to the surface of the skin
19. What is the purpose of beam filtration in diagnostic radiography? → Remove low-energy photons
20. What is the standard of care requirement for documentation standards in clinical practice? → The level of care a reasonably competent practitioner would provide
21. Which evidence-based approach is most important when applying treatment planning principles? → Integrating current research with clinical expertise and patient values
22. AAPM TG-43 provides the formalism for calculating dose rates in: → Brachytherapy source dosimetry
23. Which ethical principle is most directly applicable to clinical assessment methods? → Beneficence — acting in the patient's best interest
24. Which ethical principle is most directly applicable to treatment planning? → Beneficence — acting in the patient's best interest
25. In the context of American Board of Radiology Medical Physics Exam, what is the primary goal of patient communication? → Optimal patient outcomes and safety
26. In IMRT, what is the purpose of multi-leaf collimator (MLC) leaf sequencing? → To create complex fluence patterns that conform dose to the tumor while sparing OARs
27. What is the standard of care requirement for pharmacology basics in clinical practice? → The level of care a reasonably competent practitioner would provide
28. How should a practitioner handle an unexpected finding during pharmacology basics procedures? → Document it and follow established protocols for further evaluation
29. What is the primary mechanism of x-ray production in an x-ray tube? → Bremsstrahlung radiation
30. In the context of American Board of Radiology Medical Physics Exam, what is the primary goal of treatment planning? → Optimal patient outcomes and safety