Digital Radiography Solutions
Traditional analogue procedures that involve chemicals are linked to unpleasant odours and risks to worker health. The space, time, and financial costs of typical x-ray archives are substantial. An excellent and environmentally sustainable alternative is digital radiography. Another benefit of digital radiography over traditional radiography is that patients are exposed to less radiation. Image production and presentation processes are different between digital and analogue imaging systems. But much like regular photos, digital X-ray images are governed by the same physical laws. Digital photos are seen using a PC and display monitor rather than photographic film and a lightbox. Therefore, the switch to digital radiography simply necessitates minimal adjustments to current operations. Treatment of patients is unaffected.
What is Digital Radiography
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 then into a digital image.
Digital detector arrays (DDAs), also referred to as flat panel detectors, produce high-quality digital images in comparison to other imaging devices. They may have a higher sensitivity for radiographic applications due to their improved 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 photo diode matrix. The amount and density of the material that has absorbed the x-rays is 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 photo conductor 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 photo conductor, 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 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, producing 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 radiographic image, either the LDA or the object being inspected must move in relation to one another. LDAs are appropriate for inspecting items that are moving along a conveyor belt.
What are the Advantages of Digital Radiography?
The non-destructive testing community can benefit from digital radiography in a number of 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 chemical, hence safe for environment.
- Digital image enhancement and data storage.
- Higher productivity.
- Portability.
- Increased dynamic range enables multiple thickness to be inspected in one shot.
- Immediate feedback.
- Easy to transfer to customers electronically.
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 fibre reinforced components.
- Product and process development.
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 detection layer deposited 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 into curved spaces.
DR has numerous advantages over computed radiography despite the fact that 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.