Digital Radiographic Inspection

An instantaneous digital radiographic image is created using digital radiography (DR), an enhanced method of x-ray inspection. With this method, data is recorded while an object is being examined using x-ray-sensitive plates, and it is then instantly transferred to a computer without the necessity of a middle cassette. Through the use of a detector sensor, the incident x-ray radiation is transformed into an equivalent electric charge and ultimately into a digital image.

Digital detector arrays (DDAs), commonly referred to as flat panel detectors, produce high-quality digital images in comparison to conventional imaging systems. They may offer higher sensitivity for radiography applications due to their greater dynamic range and higher signal-to-noise ratio.

Indirect conversion and direct conversion are the two methods used by flat panel detectors. Indirect conversion flat panel detectors use a scintillator layer to transform x-ray photons into visible light photons, which are then transformed into an electrical charge by an amorphous silicon photodiode matrix. The amount and density of the substance that has absorbed the x-rays are proportional to the quantity and energy of x-ray photons interacting with the detector pixel.

The best sharpness and resolution are provided by direct conversion flat panel detectors, which use a photoconductor such as amorphous selenium (a-Se) or cadmium telluride (Cd-Te) on a multi-micro electrode plate. Thin film transistors are used to read the data from both types of detectors.

When x-ray photons collide with a photoconductor, such as amorphous selenium, they undergo a direct conversion process in which they are instantly transformed into electrical signals that are amplified and digitalized. The absence of a scintillator prevents the lateral spread of light photons, resulting in a clearer image. It differs from indirect construction because of this.

A flat panel detector can be used for x-ray computed tomography (CT) inspection, providing a 3D image of the test object’s external and internal structure when combined with the right manipulator and image processing software.

Linear detector arrays are yet another variety of digital x-ray detection media (LDAs). Instead of a matrix, these are made up of a single row of x-ray detection pixels. To create a 2D radiography image, either the LDA or the object being inspected must move about one another. LDAs are appropriate for inspecting items that are traveling along a conveyor belt.

What are the Advantages of Digital Radiography?

The non-destructive testing sector can benefit from digital radiography in several ways, including:

  • Shorter exposure times
  • Real-time applications
  • Use of analysis tool and defect-recognition software
  • Improved detail detectability
  • Enhanced SNR and linearity
  • Reduced inspection time, as no chemical processing of film, is required
  • Eliminates processing chemicals, hence safe for the environment
  • Digital image enhancement and data storage
  • Higher productivity
  • Portability
  • The increased dynamic range enables multiple thicknesses to be inspected in one shot
  • Immediate feedback
  • Easy to transfer to customers electronically

What is the Difference Between Digital and Computed Radiography?

Active matrix flat panels or linear detector arrays, which are used in digital radiography systems, are composed of a detecting layer coated over an active matrix array of thin film transistors and photodiodes. Real-time conversion of radiography images to digital data makes them instantly available for analysis.

Computed radiography cassettes take X-ray images using photo-stimulated luminescence screens rather than conventional x-ray film. The computed radiography cassette is placed into a reader, which creates a digital image from the stored data. Imaging plates for computed radiography are flexible and do not need a rigid holder. There are flexible cassettes that can be used to accommodate the detector in curved spaces.

DR has numerous advantages over computed radiography even though both have a greater dosage range and can be post-processed to remove noise. By producing better images instantly and having up to three times the dosage efficiency of computed radiography, digital radiography enhances workflow. Digital radiography is quickly replacing traditional radiography as the primary method for non-destructive testing practitioners thanks to continued technology developments and price reductions.

Digital Radiography Applications

Digital radiography has a wide range of applications, including the following:

  • Aerospace product examination
  • Detection of Corrosion Under Insulation (CUI) in petrochemical, oil, and gas, and power generation industries
  • Detection of Flow accelerated corrosion
  • Foreign object detection
  • Casting and weld inspection
  • Inspection of composites and fiber reinforced components
  • Product and process development


The term “digital radiography” (DR) refers to a variety of sophisticated radiographic examinations that use digital imaging rather than conventional film.

In comparison to conventional radiography, DR inspection techniques provide faster, safer, and more thorough inspection data. Benefits include greater image storage and archiving, better discontinuity evaluation, smaller exclusion zones, more productivity, and fewer safety risks.

Inspecting plumbing, pipelines, casting & weld quality, aerospace components, and more, MQS conducts DR inspections both in the field and in its labs all over the world.

For field inspections, MQS uses digital radiography techniques like:

  • Computed Radiography (CR)
  • MQS Automated Radiographic Testing (ART) Pipeline Crawlers
  • Fluoroscopy/Real-Time Radiography (RTR)

Computed Radiography (CR) Inspection Services

Without using film, computed radiography creates digital X-ray images. The image is recorded on a flexible, reusable imaging plate coated with a phosphor substance instead of being produced by the same X-ray-producing apparatuses as with standard X-ray testing (RT). A laser scanner is then used to scan the imaging plate, creating a digital image that may be modified, shared, and posted using a computer.

For weld inspections and on-stream wall thickness profile inspections of insulated or uninsulated pipe systems, CR inspection systems are frequently employed in the field. Additionally, it works well for lab-based casting and composite material inspection.

Most of the time, it is simple to integrate CR inspection technology into film-based systems, which eliminates the need for processing lab film, chemicals, equipment, and storage—as well as the costs related to those ancillary chores.

MQS Automated Radiographic Testing (ART) Pipeline Crawlers

It might be challenging to find internal/external corrosion and corrosion beneath insulation (CUI) in insulated and uninsulated pipelines. Advanced inspection technologies from MQS, the smart, and Through-Wall ART crawlers use Digital Radiography (DR) to discover those potentially harmful faults. The smart and Through-Wall crawlers can inspect 100% of a pipeline using this cutting-edge technology in the time it generally takes to investigate 10% using manual techniques. Additionally, these instruments allow for the simultaneous assessment of radiographic and inspection video results by operators, resulting in a speedier data collecting, processing, and analysis procedure that ultimately saves you time and money.

Other features shared by MQS’s smART and Through-Wall crawlers include:

  • Fully Wireless/Umbilical Control System
  • Unlimited Autonomous Range
  • Adaptable to Various Diameters
  • Self-Leveling Motion Control System

Fluoroscopy/Real-Time Radiography (RTR) Inspection Services

Real-Time Radiography (RTR), also known as fluoroscopy, produces a digital image that shows corrosion and internal/external flaws in real-time by emitting radiation into one side of a material and using sensors on the other side to transform the rays into the light. Traditional radiography can be faster and safer using RTR because it doesn’t need a dark room to make images.

To detect areas of pipe degradation, insulated piping systems are subjected to real-time radiography (RTR) inspections. Because RTR can conduct inspections without requiring the liner to be removed, MQS uses it as part of our corrosion under insulation (CUI) inspection programs.

An RTR pipeline crawler has also been planned and built by MQS. With the ability to do RTR inspection of pipeline girth welds at speeds much faster than conventional RT, the system is at the cutting edge of pipeline inspection technology.

Digital Radiography Testing Methods

Instead of employing conventional techniques that use x-ray film, Element’s digital radiography diagnostic methods use reusable imaging plates and Digital Detector Arrays (DDA) to digitally capture inclusions. For digital radiography testing, we primarily employ three test approaches:

  • The simplest digital radiography technique is computed radiography (CR). A high-resolution viewing monitor is used to display the image that was captured on the imaging plate (IP) after the object was exposed by x-ray tubes in cabinets.
  • A flat panel detector, commonly referred to as a digital detector array, is used in digital radiography together with specific x-ray tubes. The detector is rigid, exposure periods are lowered by 70% to 90%, and labour expenses are greatly decreased. DR’s image capture speed is quicker than that of alternative techniques.
  • DDA technology is expanded upon by computed tomography. To build a 3D image, it uses an automated detecting motion to collect thousands of digital photographs from different perspectives.

We describe the three popular NDT digital radiography modalities, their applications, and their advantages in our post The Difference Between Computed Radiography (CR) and Digital Radiography (DR) blog.

Our Level 3 qualified international professionals are on hand and prepared to suggest the best testing techniques for your upcoming projects.

Advantages of using digital radiography testing

High detection rates and exceptional image quality are provided by digital radiography (POD). Compared to traditional radiography methods, it is more affordable because there are no film or developing expenses, and the plates may be reused. Senior technicians can electronically provide the radiographic images to clients so they can view them, saving time that would otherwise be spent processing the photos. Digital radiography is more ecologically friendly and can result in more appealing pricing because the film is no longer used.

  • High-quality images
  • High probability of detection
  • Lower cost compared with conventional radiography
  • No film and film developing costs
  • Reusable plates
  • Reduced image processing time
  • Low environmental impact 

The Element Advantage

For the industries of aerospace, energy, and product testing, Element is the top testing and inspection firm. Our testing specialists guarantee the quality of your resources and completed goods while providing the assurance your radiography inspection initiatives demand.

For numerous industrial applications, we provide a variety of digital and computed radiography systems.