Computed Radiography (CR)
Computed Radiography (CR) replaces traditional X-ray film with a reusable photostimulable phosphor imaging plate that is scanned by a laser reader to produce a digital radiograph, reducing chemicals, time, and consumables.
Definition
Computed Radiography uses a photostimulable storage phosphor (PSP) imaging plate in place of film. After exposure, the plate is read by a laser scanner that releases the trapped energy as visible light, which is digitized into an image. The plate is then erased and reused.
Technical Context
CR provides a wider dynamic range than film and eliminates chemical processing, but it has lower spatial resolution than the best film systems. ASME Section V Article 2 Mandatory Appendix VI provides acceptance rules.
When It Is Used
- Construction RT where chemical processing is impractical
- In-service piping RT
- Field weld inspection
How it works
A phosphor imaging plate stores a latent image as trapped electrons; scanning it with a laser releases that energy as light which is digitised. The plate is erasable and reusable, sitting between film and direct digital detectors in workflow terms.
What it finds
Volumetric weld and casting discontinuities, with digital handling and reusable plates.
What it will not find
Fine detail beyond the scanner's spatial resolution and the plate's inherent unsharpness, which are typically coarser than a good direct digital detector. Tight planar flaws remain a radiographic weakness regardless of capture medium.
How it is actually done
Plates must be erased before use and are sensitive to background exposure and scratching; scanner resolution settings must match the required image quality class rather than being left at a default.
Governing codes and standards
ASME Section V Article 2 digital appendices; ISO 17636-2; ASTM E2033 for computed radiography practice.
Where it goes wrong
Reusing plates without verifying erasure, leaving ghost images from a previous exposure that can be mistaken for indications or can mask real ones.
Where Computed Radiography fits in an inspection programme
A term is only useful when it connects to a decision. Computed Radiography appears in written procedures, in technique sheets, and in the records an owner or accreditation body reviews afterwards — which means the way it is defined in your documentation has to match the way it is applied on site. Where the two drift apart, audits find it. Atlantis writes and reviews procedures against the governing codes, trains inspection personnel to apply them, and builds the record-keeping that makes the evidence retrievable years later. Procedure development and code consulting · NDT training and certification · Ask us about your programme.
Related terms
- Radiographic Testing (RT) — Radiographic Testing (RT) is an NDT method that uses X-rays or gamma rays to create a permanent image of the internal structure of a component on film or a digital detector, revealing porosity, cracks, inclusions, and other volumetric defects.
- Digital Radiography (DR) — Digital Radiography uses a flat-panel detector (amorphous silicon or amorphous selenium) to capture an X-ray image directly in digital form in real time, with higher signal-to-noise ratio and faster cycle time than CR or film.
Further reading
digital radiography vs film complete migration guide
More method terms
Ultrasonic Testing · Magnetic Particle Testing · Penetrant Testing · Eddy Current Testing · Visual Testing · Acoustic Emission Testing · Leak Testing · Thermography / Infrared Testing · Microwave Testing · Phased Array Ultrasonic Testing
Where this comes up in practice
Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.
Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A and ISO 9712, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.