Radiographic testing in the digital radiography era

Radiographic testing represents one of the most widely used NDT (Non-Destructive Testing) techniques in QA/QC due to its ability to provide traceable evidence of the internal condition of welds and critical components. In industrial environments, a minor discontinuity can lead to leaks, unscheduled downtime, or safety incidents; therefore, radiography maintains a vital role.

With NDT radiography, radiographic testing has evolved by incorporating image acquisition and workflow software that improve efficiency, portability, and document control. For this advancement to be effective, it is essential to understand system performance and validate quality using Image Quality Indicators (IQI) and the ASTM E747 standard.

Challenges in the Energy and Industrial Sectors

In the energy and industrial sectors, mechanical integrity competes with short maintenance windows, aging assets, and demanding audits. Consequently, this technique is used as evidence for the release of welds, repairs, and critical components.

In most cases, the problem is not a lack of technology. The true challenge lies in variability: changes in technique between crews, unstable geometries, non-uniform evaluation criteria, and incomplete records. When this variability enters the process, the impact is immediate: exposures increase, rework is required, and decision-making is slowed down by acceptance disputes that could have been avoided.

Industrial Radiography in Critical Assets

Industrial radiography allows for the evaluation of internal discontinuities where other techniques might require complex access or provide different types of evidence. This is why it is used for welds, castings, and repair verification. In welding, the radiographic technique is typically robust for volumetric discontinuities such as porosity and inclusions. It can also reveal lack of penetration or lack of fusion, depending on the geometry and arrangement.

There are limits that must be stated. Certain fine or unfavorably oriented cracks may have a low probability of detection if the setup is inadequate. In such cases, inspection is optimized through changes in geometry, additional projections, or complementary techniques.

Real Detection and Process Control

Detectability depends on energy, geometry, scatter, mounting stability, and evaluation criteria. An “aesthetic” image is not necessarily a valid shot. If sensitivity and repeatability are not demonstrated, the radiographic method loses its technical value, even if the image looks flawless.

X-ray NDT: Critical Variables and Typical Failures

X-ray NDT is defined by essential variables that control contrast, sharpness, and repeatability. If these are not governed, results will vary by operator or configuration, and the outcome loses consistency.

Energy, geometry, and dispersion

Energy (kV) affects contrast and penetration. Too high energy can flatten contrast. Too low energy can increase noise or compromise penetration.

Geometry defines sharpness and distortion. Poor mounting degrades the image, even if the equipment is high-performance, and dispersion reduces contrast and can hide details. Controlling this through collimation and technique is part of the performance of the testing technique.

Common errors in digital radiography

A common mistake is to rely on “fixing with software” what was a problem of geometry or technique. Another mistake is to allow uncontrolled display adjustments, leading to different interpretations.

A third mistake is to close the job without a robust file. If the record does not include sufficient traceability, the radiographic test becomes difficult to audit and compare.

Radiographic testing equipment and digital radiography

Radiographic testing equipment must be evaluated as a system: generation (X-rays or gamma rays), detection (CR or DR), and management (software, archiving, and reporting). Productivity improves when the process becomes stable and rework is reduced.

In digital radiography, control shifts to procedure, sensitivity verification, and post-processing governance. A stable radiographic test reduces rework and speeds up releases.

CR and DR with controlled adoption

CR offers flexibility in the field and requires scanning. DR delivers almost immediate images and promotes productivity. In both cases, it is advisable to define minimum quality criteria, roles (capture, evaluation, approval), permitted post-processing, and archiving rules. This foundation reduces variability and improves the consistency of the trial.

Image quality indicator: sensitivity

The image quality indicator (IQI) demonstrates sensitivity under real conditions. It avoids decisions based solely on appearance, especially in digital imaging, where visualization can be improved without changing actual performance. Radiographic testing is validated because the IQI demonstrates that the technique achieved the sensitivity required for that material, thickness, and configuration.

IQI as Defensible Evidence

Selecting the correct type and size, placing it properly, and recording evidence strengthens audits. It also allows for the comparison of results between different sites and providers. When the IQI is integrated, exposures due to rework are reduced and test repeatability is improved.

ASTM E747 and Radiographic Quality Control

ASTM E747 is associated with the design and use of wire-type IQIs and is usually incorporated when the procedure or the client requires it. Its operational value lies in standardizing the indicator and facilitating comparability between shots. Compliance should not be a mere formality; it must be integrated into the technique, placement, recording, and clear acceptance criteria. This strengthens the defensibility of the radiographic method.

Competency Framework and Traceability

In the industrial energy sector, inspection is executed under frameworks of codes, practices, and competency requirements. The pattern is consistent: competent personnel, controlled procedures, defined criteria, and documentary traceability.

Managing certifications, calibrations, and procedure versions reduces technical and contractual risks. It also reduces dependence on individual criteria when the radiographic test is executed across multiple sites or with various contractors.

A New Model: DÜRR NDT and Digital NDT Radiography

The DÜRR NDT interview at PANNDT 2025 serves as practical evidence of a common shift: moving from simply “taking radiographs” to governing a digital radiography system with consistent results. Their implemented model is based on:

D-Tect X: Consistent Evaluation in RT

Designed to optimize image interpretation in industrial environments. The software allows for precise zooming into specific areas, facilitating the identification of discontinuity edges. It also incorporates tools for measuring length, width, or area, and an attenuation coefficient module to help detect wall thickness differences.

• Application Example: In practice, two inspectors may interpret the same indication differently without a uniform method for visualization, measurement, and criteria. This often results in rework and unnecessary disputes during acceptance. Using tools like D-Tect X standardizes the evaluation, better defines indications, and reduces subjectivity.
• Operational Impact: The result is clear: faster, repeatable, and technically defensible decisions for QA/QC.

DriveNDT: Multi-site Workflow Control

An operational management platform designed for multi-site environments and distributed teams. With this NDT software, companies can assign tasks to technicians based on their certifications, manage competency expiration dates, control equipment calibrations, and supervise projects from any location.

• Application Example: In multi-site operations, the weak point is not the image, but the execution control: who is inspecting, with what current certification, using which calibrated equipment, and under which procedure.
• Model Insight: DriveNDT is used to assign tasks by certification, track expirations/calibrations, and monitor project status.
• Operational Impact: Fewer audit non-conformities and better process control across multiple fronts.

Flexible X-ray Panels: Access and Productivity

• Application Example: Access limits geometry, and geometry defines sharpness and detectability. With rigid detectors, certain areas force compromises or slow down the work.
• Model Insight: The use of flexible panels to adapt to confined spaces and non-standard geometries is highlighted, facilitating inspections in circumferential joints.
• Operational Impact: Greater coverage with fewer exposures and improved productivity without losing technical control.

DICONDE Standard: Regulatory Compliance

• Application Example: An image without metadata or a standardized file format is difficult to audit, share, or defend. In audits, the question is how it was obtained and how it is controlled.
• Model Insight: Emphasis is placed on compliance with the DICONDE standard and validation with independent software, including reporting, ensuring the archive is traceable and interoperable.
• Operational Impact: Stronger evidence for audits and comparability between sites.

A Comprehensive Proposal for the Future of NDT

Digital radiography is entering a new stage with this work model, where the combination of portability, digital workflow management, and regulatory compliance redefines the execution of radiographic techniques in the field. This change is not just technological; it represents a different way of governing radiographic testing in both field operations and management.

Industrial Radiography: Traditional Model vs. DÜRR NDT

Key Aspect	Traditional Industrial Radiography	DÜRR NDT Proposed Model
Process Focus	Execution of individual radiographic shots	Integrated management of the RT system
Image Acquisition	Dependent on operator and equipment	Standardized and controlled digital acquisition
Image Evaluation	Variable interpretation between inspectors	Consistent evaluation via specialized software
Sensitivity Control (IQI)	Occasional use, sometimes as a formality	Systematic IQI integration as technical evidence
Post-processing	Uncontrolled adjustments	Clear governance of permitted post-processing
Documentary Traceability	Dispersed or incomplete records	Structured and traceable digital archive
Compliance	Dependent on local procedures	Aligned with ASTM E747 and DICONDE
Multi-site Management	Difficult to coordinate between sites	Centralized and controlled workflow
Competency Control	Manual or partial tracking	Task assignment based on active certifications
Test Repeatability	Variable based on operator and setup	High repeatability across equipment and sites
QA/QC Impact	Potential acceptance disputes and rework	Faster and more defensible decisions
Operational Value	Fulfills inspection requirements	Reduces variability, rework, and decision times

Conclusions

Radiographic testing remains irreplaceable within QA/QC and mechanical integrity programs, providing objective, traceable, and technically defensible evidence for the evaluation of internal discontinuities. Its validity does not depend on whether the format is analog or digital, but on the correct governance of critical variables, the demonstration of sensitivity via IQI, and rigorous compliance with standards like ASTM, which guarantee reliability and regulatory acceptance.

Digital radiography represents a significant operational evolution by reducing inspection times, rework, and decision-making latency. However, its sustained value is only realized when integrated into a robust management model. The experience driven by DÜRR NDT, analyzed by Inspenet, demonstrates that process standardization, documentary traceability, and technical system control allow industrial radiography to scale in demanding environments, strengthening technical confidence and operational efficiency.

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References

1. ASTM International. ASTM E747: Standard Practice for Design, Manufacture, and Material Grouping Classification of Wire Image Quality Indicators (IQI) Used for Radiology. ASTM International.
2. ASTM International. ASTM E2339: Standard Practice for Digital Imaging and Communication in Nondestructive Evaluation (DICONDE). ASTM International.
3. ASNT. Recommended Practice No. SNT-TC-1A: Personnel Qualification and Certification in Nondestructive Testing. American Society for Nondestructive Testing.
4. ASME. Boiler and Pressure Vessel Code. American Society of Mechanical Engineers.
5. API. Recommended Practices and Standards for Inspection and Integrity. American Petroleum Institute.
6. Video de Inspenet. “DÜRR NDT” impulsa la radiografía digital END con innovación flexible

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