HighYield Ultrasound · QA & Accreditation
Ultrasound QA & Accreditation Toolkit
Ultrasound systems drift and transducers degrade — dead elements, lens cracks, delamination — long before the failure is obvious on a clinical image. A structured quality-assurance (QA) programme catches that decline, protects diagnostic accuracy and patient safety, and is a hard requirement for ACR, AIUM and IAC accreditation. This toolkit sets out why QA matters, the routine test set with methods, frequencies and tolerances, the phantoms and testers you need, the accreditation programmes compared, and the governance/records that tie it together — with printable log and checklist blocks.
Test methods, frequencies and tolerances summarised from AIUM Routine Quality Assurance of Clinical Ultrasound Equipment (v2.0), AAPM ultrasound QC guidance, ACR Ultrasound Accreditation and QC requirements, IAC and IPEM. Tolerances and frequencies vary by programme, equipment and jurisdiction — always follow your medical-physics service, the accrediting body’s current requirements and the manufacturer’s instructions for use.
Why QA matters
Ultrasound is often thought of as a “safe, self-calibrating” modality — the operator sees the image live, so surely a bad probe would be obvious? In practice it is not. Transducers and systems degrade gradually and invisibly: an experienced sonographer unconsciously compensates by adding gain, pressing harder or changing angle, masking a fault until it is severe enough to cost a diagnosis. QA exists to detect that hidden decline objectively, before it reaches the patient.1,2
How transducers and systems fail
Dead / weak elements
Individual piezoelectric elements fail electrically. A few dead elements produce a vertical drop-out band in the image and degrade lateral resolution and sensitivity along that line. Element loss is the single most common transducer fault and the classic reason a probe should be retired.
Lens cracks & wear
The acoustic lens/matching layer is soft and cracks, delaminates or abrades with handling and cleaning. A cracked lens causes artifact, sensitivity loss and — critically — is an infection-control and electrical-safety breach (fluid ingress to a patient-contact surface).
Delamination
Separation of the lens, matching or backing layers from the element stack. Produces reverberation artifact, dead zones and reduced penetration. Often invisible externally but obvious on a uniformity phantom.
Cable & connector faults
Flexing fractures conductors; bent connector pins drop channels. Intermittent drop-out, flicker or whole-sector loss. A frequent cause of “the machine is broken” call-outs that trace to a cable, not the system.
System / monitor drift
Beam-former, gain-calibration and above all display drift shift grey-scale rendering over time. A miscalibrated or ambient-light-swamped monitor makes correctly-acquired data look wrong.
Image-quality drift
The net result: reduced depth of penetration, degraded resolution, poorer low-contrast (cyst) detectability and non-uniformity — each of which lowers diagnostic confidence and raises the chance of a missed or mischaracterised lesion.
The three drivers of a QA programme
| Driver | What it protects | What QA delivers |
|---|---|---|
| Diagnostic quality | Accurate diagnosis — penetration, resolution, contrast and measurement accuracy | Objective, trended evidence that image quality is stable and within tolerance; early detection of drift |
| Patient safety | Freedom from electrical, burn and cross-infection hazard | Physical inspection catches cracked lenses, frayed cables and worn housings before they harm a patient |
| Accreditation & medico-legal | ACR / AIUM / IAC status, funding eligibility, defensibility | Documented equipment QC is a mandatory accreditation deliverable and a traceable record for governance and litigation |
Who does QA?
A workable programme is layered: daily/each-use visual and physical checks by the sonographer or radiographer at the point of care; periodic phantom-based image-quality tests by a designated QA lead or medical physicist; and annual comprehensive performance and electrical-safety testing by a clinical/medical physicist or qualified engineer. The exact split and cadence is set locally and by the accrediting body (Tab 2 and Tab 4).1,5
Routine QA tests
The routine test set breaks into two layers: frequent, tool-free checks anyone can do (visual/physical inspection, in-air reverberation for element drop-out), and periodic phantom-based measurements that quantify image quality against baseline. The table below is the working reference — method, who, how often and the action tolerance. Treat the figures as representative: exact tolerances and frequencies are set by your medical-physics service and accrediting body.1,3,5
QA test reference table
| Test | Method | Frequency / who | Tolerance / action |
|---|---|---|---|
| Physical / visual inspection | Inspect transducer face, lens, housing, cable and connector, and system controls/wheels/locks. Look for lens cracks, delamination, bulges, frayed cable, bent pins. | Each use / daily · sonographer | Any crack, bulge, exposed conductor or fluid ingress → remove from service. Zero tolerance for lens/housing breach. |
| Transducer element testing | Scan in air (or against a flat reflector) and inspect the reverberation pattern for vertical drop-out lines; or use a dedicated element tester (e.g. First Call). | Weekly–monthly / at fault · sonographer or physicist | Investigate any persistent drop-out band. Element-loss limits are set locally; a cluster of adjacent dead elements typically fails. |
| Image uniformity | Scan a uniform region of the tissue-mimicking phantom; assess for horizontal/vertical shadows, dead zones or bright/dark bands across the field. | Monthly–quarterly / QA lead | No new non-uniformity vs baseline. New dark bands suggest dead elements/delamination. |
| Depth of penetration (max depth of visualisation) | At maximum output and focus set deep, with gain raised, read the deepest depth at which speckle/echoes are still visible in the phantom. | Monthly–quarterly / QA lead | Typically within ≈1 cm of baseline for that probe/setting. A fall in penetration is a sensitive early sign of probe/system decline. |
| Axial resolution | Image closely-spaced resolution pins aligned along the beam axis; find the smallest pin separation resolvable in depth. | Quarterly–annual / physicist | No degradation vs baseline (better axial resolution at higher frequency is expected). |
| Lateral resolution | Image pins perpendicular to the beam at set depths; find the smallest separation resolvable side-to-side (worsens with depth and away from focus). | Quarterly–annual / physicist | No degradation vs baseline at matched depth/focus. |
| Distance / calliper accuracy | Measure known pin separations vertically (axial/depth) and horizontally (lateral) with the on-screen callipers. | Quarterly–annual / physicist | Error <3% or <3 mm, whichever is greater (axial usually held tighter, ~1–2%). |
| Anechoic-target / cystic detection | Image the anechoic (cyst-mimicking) targets at increasing depth; assess edge sharpness, correct anechoic centre and absence of fill-in. | Quarterly–annual / physicist | Smallest cyst resolved and fill-in ≥ baseline. New fill-in or missing small cysts indicates loss of low-contrast/resolution performance. |
| Grey-scale / dynamic range & low-contrast | Image stepped-echogenicity (contrast) targets; confirm the expected number of grey levels/steps is distinguishable and low-contrast targets are seen. | Quarterly–annual / physicist | Same number of grey-scale steps and low-contrast targets visible as at baseline. |
| Image uniformity & artifacts (full-field) | Full-field review for reverberation, comet-tail, drop-out and dead-zone artifacts across the image. | Quarterly–annual / physicist | No new artifacts vs baseline reference image. |
| Monitor / display QC | Assess viewing-monitor grey-scale rendering, contrast, brightness and ambient light (SMPTE / greyscale pattern); relevant to reporting workstations too. | Monthly / QA lead + annual physicist | All grey-scale steps distinguishable; display within calibration; control ambient light. |
| Doppler performance (where used) | On a Doppler flow phantom: velocity accuracy, sample-volume/gate position, colour box registration, sensitivity/penetration and flow direction. | Annual / physicist (IAC-accredited vascular/echo) | Velocity error within programme tolerance; correct colour registration and direction. |
| Electrical safety | Leakage-current and earth-continuity testing of the system and transducers per the medical-electrical-equipment standard. | Annual / biomedical engineer | Within IEC 60601 leakage limits; fail → out of service. |
Test equipment & phantoms
QA measurements are only as good as the test object behind them. Ultrasound QA uses tissue-mimicking phantoms (grey-scale/B-mode), Doppler flow phantoms and dedicated element testers. Each answers a different question.6,7
Tissue-mimicking (grey-scale) phantoms
A tissue-mimicking phantom is a block of material whose speed of sound (~1540 m/s) and attenuation mimic soft tissue, with embedded targets. It is the workhorse of B-mode QA. Major vendors include CIRS, Gammex/Sun Nuclear and ATS (CIRS).
| Embedded target | What it measures |
|---|---|
| Background tissue-mimicking gel | Depth of penetration (max depth of visualisation); overall sensitivity and uniformity |
| Vertical pin group | Axial (depth) distance/calliper accuracy |
| Horizontal pin group | Lateral (horizontal) distance/calliper accuracy |
| Closely-spaced pin pairs | Axial and lateral spatial resolution |
| Anechoic (cystic) targets, varied size/depth | Cyst detectability, edge sharpness, fill-in — low-contrast performance |
| Stepped grey-scale / contrast targets | Grey-scale, dynamic range and low-contrast object detectability |
Doppler flow phantoms
Grey-scale phantoms cannot assess flow. A Doppler flow phantom pumps a blood-mimicking fluid through a vessel at a known velocity within tissue-mimicking surround, letting you verify:
- Velocity accuracy — does the measured velocity match the set flow?
- Sample-volume / gate placement and spectral display
- Colour-flow box registration, sensitivity and correct flow direction
- Doppler penetration — deepest depth flow is still detected
These are the tests that matter for IAC-accredited vascular and echocardiography services, where velocity measurements drive diagnosis (e.g. carotid stenosis thresholds).8
Element / transducer testers
Dedicated tools drive each element and read its response to detect dead or weak elements more objectively than the in-air method. The best-known is FirstCall (Sonora/Unisyn), which produces a per-element report. Handheld/impedance testers also flag element and cable faults. These are especially valuable for a fleet, where systematic element mapping catches decline early and supports repair-vs-replace decisions.
Tissue-mimicking phantom
B-MODEPenetration, resolution, distance accuracy, cyst detection, grey-scale/uniformity. The core QA test object.
Doppler flow phantom
DOPPLERVelocity accuracy, colour registration, flow sensitivity/penetration. Essential for vascular/echo QA.
Element tester (FirstCall)
TRANSDUCERPer-element drive/response mapping — objective dead-element detection and fleet surveillance.
Display test pattern
MONITORSMPTE / grey-scale pattern for viewing-monitor and reporting-workstation QC.
Accreditation programmes
In many jurisdictions QA is not optional — it is the price of accreditation, and accreditation is often the price of reimbursement. The main programmes overlap heavily on principle (documented QC, qualified personnel, image-quality review) but differ in scope and detail. All require reaccreditation every 3 years.9,10,11
| Programme | Scope | Clinical image-quality review | Personnel & CME | Equipment QC & documentation |
|---|---|---|---|---|
| ACR Ultrasound (US)9 | General, OB, gynae, vascular, paediatric modules — apply for every module the site performs. | Submit clinical images + measurements per module; reviewed against ACR criteria; phantom images may be requested. | Physician/interpreting-provider qualifications + sonographer credentialing; ongoing CME. | QC documented to stated minimum frequencies (routine QC no longer submitted with the application, and semiannual QC no longer required — but QC must still be performed & recorded). |
| AIUM Practice Accreditation (US)10 | Whole-practice accreditation across the specialties performed. | Case submission reviewed against AIUM standards; final-report standards applied. | Designated Director of Ultrasound (licensed provider meeting AIUM training guidelines); sonographers registered in each specialty within one cycle; ≥1 registered sonographer per specialty. | Standards for QA of clinical practice, equipment maintenance/calibration and record-keeping. |
| IAC — Vascular Testing (US)11 | Vascular-lab accreditation (carotid, venous, arterial, etc.). | Case studies submitted for peer review; strong emphasis on measurement/velocity accuracy and reporting. | Medical director + technical staff; sonographer credentialing requirement; CME. | Documented QA/QI programme, equipment maintenance and Doppler performance; self-evaluation against IAC Standards. |
| IAC — Echocardiography (US)11 | Adult/paediatric TTE, TEE, stress echo. | Case review of studies and reports against IAC echo Standards. | Medical director, sonographer credentialing, CME. | QA/QI programme, equipment QC including Doppler/velocity performance. |
| UK / Europe (IPEM, national)5 | Governed through clinical-governance/quality frameworks rather than a single US-style accreditation body; IPEM/EFSUMB give the technical QA standard; UK bodies (e.g. via UKAS-type schemes) accredit services. | Local governance + peer review; national imaging-quality frameworks. | Professional registration (e.g. HCPC), recognised training, CPD. | Medical-physics-led routine QA to IPEM guidance; documented programme and records. |
Governance & records
A test that is not recorded, trended and acted on is not QA — it is a chore. Governance is what turns individual measurements into a defensible, closed-loop programme: logs, action limits, escalation, decontamination records and audit. This is exactly what an accreditation visit inspects.1,9
Action limits & escalation
Every trended parameter needs a defined action limit and an owner. A simple three-tier scheme works:
| Level | Trigger | Action |
|---|---|---|
| PASS | Within tolerance of baseline | Log result, continue in service, watch the trend. |
| INVESTIGATE | Drift approaching tolerance, or a new minor artifact | Repeat test, check technique/phantom, log, notify QA lead, schedule physics review. |
| FAIL / STOP | Out of tolerance; cracked lens; failed electrical safety; dead-element cluster | Remove transducer/system from clinical use, tag out, log the fault, escalate to physics/engineering, re-baseline after repair. |
Records to keep
- Equipment inventory — every system and transducer with serial number and acceptance-test baseline reference image.
- QA test logs — dated results per test per transducer, with the phantom/tester used and the operator.
- Fault & action log — failures, investigations, repairs, and re-baseline dates; tag-out records.
- Decontamination / reprocessing records — HLD cycles and probe-to-patient traceability (medico-legal for endocavity/interventional probes).
- Training & competency — who is authorised to perform which QA task; credentialing and CME/CPD.
- Audit & review minutes — periodic QA/QI meeting that reviews trends, incidents and accreditation status.
Printable QA log & checklists
Site: ______________ System: ______________ Serial: ______________ Week commencing: ____________
- Transducer face & lens intact — no cracks, bulges or delamination
- Housing intact; no exposed conductor or fluid ingress
- Cable & strain relief undamaged; connector pins straight
- In-air reverberation check — no vertical drop-out band
- Controls, wheels, brakes & monitor arm functional
- Viewing monitor clean; grey-scale steps distinguishable; ambient light controlled
- Probe reprocessing status confirmed before first patient
Result: PASS / INVESTIGATE / FAIL · Signed: ______________ Date: __________
| Test | Baseline | Result | Tolerance | Pass / Fail |
|---|---|---|---|---|
| Depth of penetration (cm) | within ~1 cm of baseline | |||
| Axial distance accuracy | <3% or <3 mm | |||
| Lateral distance accuracy | <3% or <3 mm | |||
| Axial resolution | = baseline | |||
| Lateral resolution | = baseline | |||
| Smallest anechoic target seen | ≥ baseline | |||
| Grey-scale steps visible | = baseline | |||
| Uniformity / artifacts | no new artifact |
Transducer: __________ Phantom model: __________ Performed by: __________ Date: __________ Physics reviewed: __________
Downloadable QA log workbook
HighYield Ultrasound Pro members get the full editable QA workbook: acceptance-test/baseline sheet, daily inspection log, periodic phantom-QA log with auto-trending charts, Doppler-phantom log, element-map tracker, fault & action register, and an accreditation-evidence bundle mapped to ACR / AIUM / IAC requirements — plus printable wall-charts for the scan room.
Free on this page: the daily inspection checklist and periodic phantom-QA log above. Upgrade for the editable multi-tab workbook and accreditation mapping.
References
- American Institute of Ultrasound in Medicine. Routine Quality Assurance of Clinical Ultrasound Equipment, Version 2.0. AIUM. (Test set, methods, frequencies, baseline-comparison principle.)
- American College of Radiology. Quality Control: Ultrasound and Breast Ultrasound (revised 2025). ACR Accreditation Support. (Transducer inspection, QC requirements.)
- Hangiandreou NJ, et al. Phantom-based quality assurance measurements in B-mode ultrasound. (Penetration, resolution, distance accuracy; distance tolerance <3% or <3 mm.)
- American College of Radiology. Complete Accreditation Information: Ultrasound (revised 1-24-2024). ACR Accreditation Support.
- Institute of Physics and Engineering in Medicine. Routine Quality Assurance of Ultrasound Imaging Systems (IPEM Report 102 and related guidance). IPEM. (UK/European technical QA standard.)
- American Association of Physicists in Medicine. Real-Time B-Mode Ultrasound Quality Control Test Procedures (AAPM Report No. 65 / TG-1). AAPM. (Phantom-based QC test procedures.)
- American Association of Physicists in Medicine. Quality Assurance of Ultrasound Imagers: Procedures, Expectations and Philosophies. AAPM educational course. (Phantoms, testers, expectations.)
- American Association of Physicists in Medicine. AAPM Task Group 128: Quality assurance tests for prostate brachytherapy ultrasound systems. AAPM. (Doppler/flow & geometric QA methodology.)
- American College of Radiology. ACR Ultrasound Accreditation. ACR. (Modules, clinical image submission, QC documentation, 3-year cycle.)
- American Institute of Ultrasound in Medicine. Standards and Guidelines for the Accreditation of Ultrasound Practices. AIUM. (Director of Ultrasound, sonographer registration, QA/equipment/record-keeping standards.)
- Intersocietal Accreditation Commission. IAC Standards & Guidelines for Vascular Testing Accreditation (and Echocardiography Standards). IAC. (Self-evaluation, case submission, sonographer credentialing, QA/QI, 3-year cycle.)
- Nyhsen CM, Humphreys H, Koerner RJ, et al. Infection prevention and control in ultrasound — best practice recommendations (ESR Ultrasound Working Group). Insights Imaging 2017;8:523–535. (Probe damage and reprocessing cross-link.)
- Goodsitt MM, Carson PL, Witt S, et al. Real-time B-mode ultrasound quality control test procedures. Report of AAPM Ultrasound Task Group No. 1. Med Phys 1998;25(8):1385–1406.
- Sun Nuclear / Gammex. Ultrasound tissue-mimicking QA phantoms — product & test-object documentation. (Grey-scale phantom targets.)
- CIRS (Computerized Imaging Reference Systems). Multipurpose and Doppler flow ultrasound phantoms. CIRS. (Tissue-mimicking and Doppler flow test objects.)
- Sonora Medical / Unisyn. FirstCall transducer testing — per-element performance testing. (Dead-element detection and fleet surveillance.)
- International Electrotechnical Commission. IEC 60601-1 / 60601-2-37 — medical electrical equipment safety, including diagnostic ultrasound. IEC. (Electrical-safety/leakage limits.)
- Pye SD, Ellis W. Development and implementation of a quality control protocol for B-mode ultrasound equipment. (Practical QC protocol, tolerances, in-service testing.)
This page is an educational summary for imaging professionals and students. It is not clinical, regulatory or accreditation advice and does not replace your medical-physics service, the accrediting body’s current published Standards, employer’s procedures, local infection-control policy, or the equipment manufacturer’s instructions for use. QA test lists, tolerances and frequencies, and accreditation requirements, are periodically revised and vary by programme, equipment and jurisdiction — always confirm against the current primary source before relying on a value in practice. © HighYield Ultrasound.