Skip to main content

Radiographic Acceptance Testing & Annual Survey

By Troy Zhou, PhD, DABR, DABSNM
• 16 min read
#Quality Control #Accreditation #Image Quality #Patient Safety #Dosimetry

Radiographic acceptance testing establishes a new or repaired X-ray unit's performance baseline against manufacturer specifications and regulatory limits; the periodic physics survey confirms the unit still meets that baseline over time. The two are related but distinct activities, and a defensible quality program treats them that way: acceptance testing is the comprehensive, one-time characterization at installation, while the survey is the recurring check that drift, wear, and component failure have not pushed the unit out of tolerance.

Both are the work of a qualified medical physicist (QMP), and both end in a signed report that a facility relies on for regulatory review, accreditation, and clinical confidence. This guide explains what each evaluation covers, which tolerances apply and where they come from, the governing standards as they stood at the start of 2026, and how the QMP's role fits with the technologist-level ongoing quality control that runs between surveys. It is written for general diagnostic radiographic rooms — not CT, mammography, or fluoroscopy, which have their own dedicated standards.

Introduction

Every radiographic unit degrades. Tubes age, collimator lamps dim, automatic exposure control (AEC) chambers drift, detectors accumulate bad pixels, and calibration slips. The purpose of acceptance testing is to know exactly how the unit performed when it was new or freshly repaired, and the purpose of the periodic physics survey is to confirm it still performs that way — or to catch the degradation before it affects image quality or patient dose.123

The distinction matters because the two evaluations answer different questions. Acceptance testing asks: does this unit meet what we bought and what the regulations require? The baseline it records — tube output per unit of exposure, half-value layer (HVL), beam alignment, AEC behavior — becomes the reference. The periodic survey asks: does the unit still match its baseline and stay within regulatory limits? A survey that finds a 15% drift in output from baseline is meaningful only because the baseline exists.36

This framework is the backbone of DRPS diagnostic radiography physics services, and it is also the structure most state radiation-control programs and accreditation bodies expect to see documented.

Topic Explanation

What is acceptance testing?

Acceptance testing is the comprehensive evaluation a QMP performs when a radiographic unit is new, relocated, or significantly modified, to verify it meets manufacturer specifications and regulatory requirements before clinical use. It is performed once per installation or major change, and it is deliberately thorough because its results become the baseline for the unit's entire service life.3

A radiographic acceptance test typically documents, at minimum:

  • Mechanical and safety inspection (collimator, interlocks, exposure switches, cabling, mechanical stability).
  • Beam quality: half-value layer and total filtration adequacy.
  • Tube potential (kVp) accuracy and reproducibility.
  • Exposure timer accuracy.
  • Output: air kerma per unit of tube current–time product (mGy/mAs), reproducibility, and linearity.
  • Light-field to X-ray-field congruence and beam perpendicularity.
  • AEC performance across thickness and kVp, chamber consistency, and backup timer.
  • Detector performance for the digital imaging system (uniformity, signal response, and spatial resolution appropriate to the system).

For digital radiographic systems, the current consensus reference for the physicist's acceptance tests is AAPM Report No. 150 (Task Group 150); for computed radiography (photostimulable storage phosphor) systems, AAPM Report No. 93 (Task Group 10) remains the applicable acceptance and QC reference.35 The older AAPM Report No. 74 framework has been superseded for digital work by Reports 150 and 151 and should be treated as historical background rather than current guidance.

What is the periodic physics survey?

The periodic physics survey is the recurring evaluation — often annual, but set by the governing rule — that confirms a radiographic unit still performs within its baseline and within regulatory limits. It is usually a focused subset of the acceptance test, oriented toward the parameters most likely to drift and most consequential for dose and image quality.36

The survey is not the only quality activity between installations. Day-to-day and week-to-week ongoing QC — reject-image analysis, exposure-index monitoring, and artifact identification — is performed by radiologic technologists under the physicist's direction, as described in AAPM Report No. 151 (Task Group 151).4 The survey and the ongoing QC program are complementary: the technologist-level program catches fast-developing problems between surveys, and the QMP survey provides the periodic, calibrated, independent check. For more on the technologist-level program, see our guides to repeat-reject analysis and the digital radiography exposure index.

Key Technical Principles

Where the tolerances come from

A recurring source of confusion is which numbers are regulatory and which are consensus practice. They are not the same, and a defensible report should not present a consensus tolerance as a federal requirement.

The U.S. federal performance standards for diagnostic X-ray equipment are in 21 CFR 1020.30 (systems and major components) and 21 CFR 1020.31 (radiographic equipment). These set mandatory requirements including:12

  • Exposure reproducibility: the estimated coefficient of variation of air kerma must be no greater than 0.05.
  • Output linearity: the average air kerma per mAs must not differ by more than 0.10 of their sum between adjacent tube-current (or mAs) settings.
  • Light-field / X-ray-field alignment: within 2% of the source-to-image receptor distance (SID) for each edge, and for positive-beam-limitation systems, the field center within 2% of SID.
  • SID indication accuracy: within 2% of SID.
  • Minimum half-value layer: a minimum HVL applies at each tube potential to confirm adequate beam filtration; for example, for systems manufactured on or after June 10, 2006, the minimum HVL is on the order of 2.1 mm aluminum at 71 kVp and 2.5 mm aluminum at 90 kVp (consult the applicable table for the exact value at a given kVp and manufacture date).

Consensus tolerances from AAPM come on top of the federal floor, not instead of it. For example, AAPM Report No. 150 and common state practice use a kVp accuracy tolerance of within 5 kV or 5%, whichever is greater, and an exposure-timer accuracy near 1 ms for very short exposures — practice limits that the federal standard does not itself specify.3 The IEC 61223-3-8 acceptance and constancy test standard and IAEA Human Health Series No. 47 provide international frameworks for the same parameters.79

The table below separates the two categories for a few representative parameters.

Parameter Typical tolerance Source / type
Exposure reproducibility Estimated coefficient of variation ≤ 0.05 21 CFR 1020.31 — federal requirement 2
Output linearity (adjacent settings) ≤ 0.10 of the sum of adjacent mGy/mAs values 21 CFR 1020.31 — federal requirement 2
Light-field / X-ray-field alignment Within 2% of SID per edge 21 CFR 1020.31 — federal requirement 2
SID indication Within 2% of SID 21 CFR 1020.31 — federal requirement 2
Minimum HVL Table value by kVp (e.g., ~2.5 mm Al at 90 kVp) 21 CFR 1020.30 — federal requirement 1
kVp accuracy Within 5 kV or 5%, whichever is greater AAPM Report 150 — consensus practice 3
Exposure timer accuracy ~1 ms for exposures ≤ 20 ms AAPM Report 150 — consensus practice 3

Worked example: output reproducibility

Reproducibility is one of the most basic acceptance and survey tests, and it illustrates how the federal coefficient-of-variation limit is actually computed. The coefficient of variation (CoV) is the sample standard deviation of repeated air-kerma readings divided by their mean, and the limit is:2

Suppose a physicist makes five exposures at a fixed technique (say 80 kVp, 10 mAs) and records air-kerma readings of 2.05, 2.02, 2.08, 2.00, and 2.06 mGy. The mean is:

The sample standard deviation is:

So the coefficient of variation is:

Because 0.016 is well below 0.05, the unit passes the reproducibility requirement with comfortable margin. A companion test, output linearity, checks that output per mAs is consistent across adjacent settings using the criterion that the difference between two adjacent average mGy/mAs values be no more than 0.10 of their sum; for instance, 0.052 and 0.048 mGy/mAs give a value of 0.004 / 0.100 = 0.04, which passes.2 For the deeper QC background on these parameters, see our articles on kVp accuracy and reproducibility QC and half-value layer and kVp radiography QC.

Clinical Impact

Acceptance testing and periodic surveys protect both image quality and patient dose, which is why they are worth doing well rather than treating as a checkbox. A unit that drifts out of tolerance produces one of two failure modes, and both are harmful.

If output drifts high or the AEC under-terminates, patients receive more dose than necessary for the diagnostic task — the quiet, cumulative kind of over-exposure that reject-and-repeat studies repeatedly surface. Audits of digital radiography reject rates have found overall reject rates around 10%, with positioning the leading cause, underscoring how much repeated exposure a department can carry without a disciplined QC program.10 If output drifts low or beam quality degrades, images become noisy, technologists compensate with higher techniques, and the dose savings of digital imaging evaporate. Exposure-index tracking across multiple units has revealed differences large enough to represent a 60% difference in detector dose between units nominally calibrated to the same target — differences invisible case by case but obvious in the aggregate.11

The periodic survey is what keeps these drifts bounded. By comparing current performance to the acceptance baseline, the QMP can distinguish normal variation from a developing fault and recommend correction before it reaches patients. This is the same logic behind national diagnostic reference levels and achievable doses, which use survey data to benchmark typical practice.12

Practical Optimization Tips

A radiographic acceptance and survey program runs best when the facility treats it as a system, not a once-a-year visit.

1. Keep the baseline accessible and specific

  • Record the acceptance baseline for every measured parameter, with the technique, geometry, and instrument used.
  • Store it where the next physicist and the technologist QC program can find it; a baseline no one can locate is not a baseline.

2. Separate acceptance from the survey — and schedule both

  • Perform full acceptance testing at installation, relocation, or significant repair (for example, tube or generator replacement).
  • Schedule the periodic survey at the interval the governing rule or accreditation program requires, and document the date and result.

3. Run the ongoing technologist QC between surveys

  • Implement reject-image analysis, exposure-index monitoring, and artifact checks per AAPM Report 151, performed by technologists under the physicist's direction.4
  • Trend the results rather than only pass/failing them; a slow drift is only visible over time.

4. Match the instrument and method to the test

  • Use a calibrated, traceable kVp/dose meter appropriate to the beam qualities being tested.
  • Confirm the test geometry (distances, field sizes) matches the baseline conditions so the comparison is valid.

5. Write a report a regulator can read

  • State each parameter, its measured value, the applicable tolerance, the source of that tolerance, and the pass/fail result.
  • Flag any deviation from baseline, not just regulatory failures — a within-limit value that has drifted markedly from baseline is a warning.

Regulatory Considerations

Radiographic equipment sits under federal performance standards, state radiation-control registration and survey rules, and — where applicable — accreditation requirements. Getting the regulatory framing right matters, because overstating a requirement is as much an error as missing one.

  • Federal performance standards. 21 CFR 1020.30 and 1020.31 set the manufacturing and performance requirements the equipment itself must meet (reproducibility, linearity, HVL, alignment, SID indication). These apply to the equipment and are the backbone of the acceptance test.12
  • State radiation-control programs. X-ray machines are regulated by state (and, for the underlying performance standard, federal FDA) authority, not by the NRC. Most states require registration of X-ray machines plus a survey by a qualified person. The frequency and trigger vary: a survey is commonly required for new facilities, never-previously-surveyed facilities, and after any modification that could significantly increase the radiation hazard, with the report submitted to the state within a set window. State inspection frequency is typically risk-based — more frequent for higher-risk modalities, less frequent for low-risk machines. For example, Florida administers X-ray requirements under Chapter 64E-5, Part V, which requires a survey by or under the direction of a qualified person for new and never-surveyed facilities and after significant changes.13 A blanket, nationwide "annual medical physicist survey of every radiographic room" is a common misconception; the one clear federal annual-physicist-survey mandate is for mammography under MQSA, which is a separate program.
  • Accreditation and the QMP's role. The ACR–AAPM technical standard for diagnostic medical physics performance monitoring of radiographic equipment describes the qualified medical physicist's responsibilities for evaluating performance at installation and monitoring it periodically.8 Accreditation programs and some license conditions require a QMP's evaluation and signed report. For the credentialing framework behind "qualified," see our guide to qualified medical physicist credentials and standards and our overview of ACR accreditation physics requirements.

Because the specific survey interval and trigger depend on the state and the machine type, a facility should confirm its obligations against the current rule in its jurisdiction rather than assume a single national cadence. DRPS supports this through accreditation support and medical physicist consulting.

Frequently Asked Questions (FAQs)

What is radiographic acceptance testing?

Acceptance testing is the set of measurements a qualified medical physicist performs on a new, relocated, or significantly repaired radiographic unit to confirm it meets manufacturer specifications and regulatory requirements before clinical use. It establishes the baseline values that every later periodic survey is compared against.

How is acceptance testing different from the annual physics survey?

Acceptance testing is a one-time, comprehensive evaluation against manufacturer specifications and purchase requirements when equipment is installed or substantially modified. The periodic (often annual) physics survey is a recurring, usually shorter evaluation that confirms the unit still performs within its established baseline and within regulatory limits over time.

Who can perform a radiographic physics survey?

A qualified medical physicist (QMP) — typically board-certified in diagnostic medical physics — performs or directs acceptance testing and the periodic survey. Many state radiation-control programs, accreditation bodies, and license conditions require a QMP's evaluation and signed report.

What tolerances apply to radiographic equipment?

Federal performance standards in 21 CFR 1020.31 set requirements such as exposure reproducibility (estimated coefficient of variation no greater than 0.05) and output linearity (no more than 0.10 between adjacent settings), plus light-field/X-ray-field alignment within 2% of the source-to-image distance. Consensus tolerances from AAPM reports add practice limits such as kVp accuracy within 5 kV or 5%, whichever is greater.

Is an annual medical physicist survey of every X-ray machine required by law?

No, not universally. Requirements vary by state and by machine type. Most states require registration of X-ray machines plus a survey by a qualified person for new facilities, never-surveyed facilities, and after modifications that could increase radiation hazard, with inspection frequency set on a risk basis. Mammography is the notable federal exception, requiring an annual physicist survey under MQSA. Always confirm the specific requirement against the current state rule.

What standards govern radiographic QC?

Federal performance standards appear in 21 CFR 1020.30 and 1020.31. Current consensus guidance for digital radiography includes AAPM Report No. 150 for physicist acceptance and QC and AAPM Report No. 151 for ongoing technologist QC. IEC 61223-3-8 and IAEA Human Health Series No. 47 provide international acceptance and constancy test frameworks, and the ACR–AAPM technical standard describes the physicist's performance-monitoring role.

Key Takeaways

  • Acceptance testing sets the baseline; the survey confirms it holds. The two are distinct activities with distinct purposes, and both belong in a defensible program.3
  • Know which tolerances are regulatory. 21 CFR 1020.30/1020.31 set mandatory reproducibility, linearity, HVL, and alignment requirements; AAPM consensus tolerances (e.g., kVp within 5 kV or 5%) sit on top of that floor.123
  • Reproducibility is a coefficient-of-variation test. The estimated CoV of repeated air-kerma readings must be no greater than 0.05.2
  • Ongoing technologist QC fills the gaps between surveys. Reject analysis, exposure-index monitoring, and artifact checks per AAPM Report 151 catch fast-developing problems.41011
  • Do not overstate the survey mandate. Most states require registration plus a qualified-person survey with risk-based frequency; a universal annual physicist survey of every radiographic machine is not the national rule (mammography under MQSA is the exception).13
  • The output is a defensible report. Every parameter, tolerance, source, and result documented, with deviations from baseline flagged.

Conclusion

A radiographic quality program is only as good as the baseline it is built on and the discipline that maintains it. Acceptance testing is the investment that makes every later survey meaningful: it captures, in calibrated detail, how a unit performs when it is known to be good. The periodic survey then does the quieter but equally important work of confirming that the unit has not drifted, and the ongoing technologist QC program keeps watch in between.

For the medical physicist and the facility, the goal is not simply to pass an inspection. It is to run radiographic equipment that is correctly characterized, correctly maintained, and correctly documented — so that image quality is reliable, patient dose stays appropriate to the task, and the program is defensible when a regulator or accreditor asks to see the evidence.

How DRPS Can Help

Diagnostic Radiation Physics Services performs radiographic acceptance testing and periodic physics surveys, establishes and reviews baselines, designs ongoing technologist QC programs, and prepares the signed reports that facilities rely on for state registration, accreditation, and license conditions. Our work is performed by board-certified medical physicists and aligned with 21 CFR 1020.30/1020.31, current AAPM guidance, and the applicable state radiation-control rules.

DRPS supports facilities across our service locations, including Florida, Maryland, Virginia, Washington DC, California, Nevada, New York, Pennsylvania, New Jersey, and Delaware.

A strong acceptance-and-survey program makes the safe, in-tolerance unit the default — not something a facility hopes for between inspections.

Related Resources

References

  1. U.S. Food and Drug Administration. 21 CFR 1020.30: Diagnostic x-ray systems and their major components. ecfr.gov
  2. U.S. Food and Drug Administration. 21 CFR 1020.31: Radiographic equipment. ecfr.gov
  3. American Association of Physicists in Medicine. Acceptance Testing and Quality Control of Digital Radiographic Imaging Systems. AAPM Report No. 150 (Task Group 150). College Park, MD: AAPM; 2024. aapm.org
  4. Jones AK, Heintz P, Geiser W, et al. Ongoing quality control in digital radiography: Report of AAPM Imaging Physics Committee Task Group 151. Med Phys. 2015;42(11):6658-6670. doi:10.1118/1.4932623. PubMed
  5. American Association of Physicists in Medicine. Acceptance Testing and Quality Control of Photostimulable Storage Phosphor Imaging Systems. AAPM Report No. 93 (Task Group 10). College Park, MD: AAPM; 2006. doi:10.37206/94. aapm.org
  6. National Council on Radiation Protection and Measurements. Quality Assurance for Diagnostic Imaging. NCRP Report No. 99. Bethesda, MD: NCRP; 1988. ncrponline.org
  7. International Electrotechnical Commission. Evaluation and routine testing in medical imaging departments — Part 3-8: Acceptance and constancy tests — Imaging performance of X-ray equipment for radiography and radioscopy. IEC 61223-3-8:2024. Geneva: IEC; 2024. iec.ch
  8. American College of Radiology; American Association of Physicists in Medicine. ACR–AAPM Technical Standard for Diagnostic Medical Physics Performance Monitoring of Radiographic Equipment. Revised 2021. aapm.org
  9. International Atomic Energy Agency. Handbook of Basic Quality Control Tests for Diagnostic Radiology. IAEA Human Health Series No. 47. Vienna: IAEA; 2023. iaea.org
  10. Stephenson-Smith B, Neep MJ, Rowntree P. Digital radiography reject analysis of examinations with multiple rejects: an Australian emergency imaging department clinical audit. J Med Radiat Sci. 2021;68(3):245-252. doi:10.1002/jmrs.468. PubMed
  11. Scott AW, Zhou Y, Allahverdian J, Nute JL, Lee C. Evaluation of digital radiography practice using exposure index tracking. J Appl Clin Med Phys. 2016;17(6):343-355. doi:10.1120/jacmp.v17i6.6082. PubMed
  12. National Council on Radiation Protection and Measurements. Reference Levels and Achievable Doses in Medical and Dental Imaging: Recommendations for the United States. NCRP Report No. 172. Bethesda, MD: NCRP; 2012. ncrponline.org
  13. Florida Department of Health. Florida Administrative Code, Chapter 64E-5, Control of Radiation Hazards (Part V, X-rays in the Healing Arts). floridahealth.gov

Related Articles