Back to a Digital Future
Being unable to view a Blu-ray DVD on an HD-DVD player may be an exasperating inconvenience. But being unable to view, access, store or exchange inspection data for key components of, say, aging nuclear power plants, aircraft or bridges potentially imperils public health and safety. It also limits the value of that data for evaluating a component's performance over its service life.
"Every year, new technologies produce new modalities for testing," notes Yehuda Rosenstock, director of research and development at Air Techniques Inc., in Melville, N.Y., and a member of ASTM International Committee E07 on Nondestructive Testing. "Very few companies have all the hardware and software they need to deal with all the different testing modalities," Rosenstock says. He adds, "Systems have to be able to talk to each other."
For nearly a decade, ASTM Subcommittee E07.11 on Digital Imaging and Communication in Nondestructive Evaluation (DICONDE), a part of Committee E07, has been developing standards to facilitate the exchange and storage of nondestructive evaluation data. As E07 member Lloyd Arrowood, a physical testing engineer in the Product Certification Organization of Babcock and Wilcox Y-12 Technical Services, Oak Ridge, Tenn., explains, "Standardized metadata and system interoperability are the best ways we can ensure that inspection data is available 20, 40 and even 60 years or more into the future over the lifetime of a product."
The NDE industry uses a variety of inspection modalities, including ultrasound, computed tomography, neutron radiography and electromagnetism, to check for internal flaws - like cracks or foreign materials - in the components of all sorts of products produced in a wide variety of industries. The intent is to discover anomalies or to monitor conditions that might cause health, safety or performance issues.
Historically, the NDE industry has relied on proprietary formats to store inspection data. While those formats have advantages in terms of efficiency and flexibility, they also have limitations when it comes to data interchange and migration, especially when applied to components in products with a 20- to 40-year life span, such as military and commercial aircraft or nuclear power plants. Over such long periods of time, the need to access inspection data remains, even as the equipment that initially acquired that data and the computer hardware that stored it are retired or upgraded.
In the 1980s, the healthcare industry faced a similar problem. When manufacturers of medical imaging devices initially used proprietary communication and data exchange mechanisms, it was difficult for hospitals and clinicians to easily access and view patients' X-rays and other diagnostic images over the course of the patients' lives. The different systems and equipment simply didn't communicate with each other.
In response, manufacturers and users of medical digital imaging equipment formed the Digital Imaging and Communications in Medicine Committee (DICOM). By the mid-1980s, the committee published the American College of Radiology – National Electrical Manufacturers Association standard (ACR-NEMA 300-1985, Digital Imaging and Communications Standard) allowing digital images produced by different equipment to be shared and viewed in a common format. Ten years later, the DICOM standard achieved near universal acceptance among medical imaging equipment manufacturers and healthcare information technology organizations. Today, even patients with copies of their MRIs taken by different equipment can download software to view their digital images on a home computer.
Based on the success of the DICOM standard, in the late 1990s, a group of NDE experts began working with ASTM to form ASTM Subcommittee E07.11 on Digital Imaging and Communication in Nondestructive Evaluation. The goal was to develop an NDE industry standard based on the DICOM standard. In 2004, the subcommittee published E2339, Practice for Digital Imaging and Communication in Nondestructive Evaluation (DICONDE), which allows wide-scale adoption of a common standard for data storage and exchange.
Instead of a patient information module, including patient name and patient identification, the DICONDE standard uses a component module with such standardized metadata as a component name and serial number as well as component shape and environmental conditions. In addition to building on DICOM'S data storage capabilities, the DICONDE standard also utilizes DICOM's communications capabilities and employs image data display features that are not found in other commonly used data storage standards, such as TIFF or JPEG. Such advanced features allow NDE industrial users to view remote digital data on their computers, readily share inspection data that indicate equipment component flaws or potential problems, view archived data exactly as it was viewed by inspectors at the time an inspection was conducted, and eliminate paper records by having convenient computer access to all digital data. Additionally, there are a wide variety of DICOM-compatible tools, such as picture-archiving systems, image review software and open source software, that can be easily adapted for use with the DICONDE standards.
One organization that has benefited from using the original DICONDE standard is Babcock and Wilcox Y-12 Technical Services, a managing contractor for the U.S. Department of Energy that performs radiographic inspections of nuclear weapons components. While inspection data is required to be maintained for the life of a weapons program, over time, a number of inspection processes have been transformed from film-based to digital radiography.
In 2007, the company began using a suite of software tools that comply with ASTM E2339. Says Babcock and Wilcox's Arrowood, "The software enables us to collect radiographic data at different locations and transmit it to a central location where our most skilled inspectors make evaluations." Additionally, standardized metadata, storage and communications protocols ensure that the type of data collected is consistent, that it can migrate to new storage media and that interoperability is maintained, even as new technologies, hardware and software are developed, and vendors leave and enter the NDE market.
According to Arrowood, despite adoption of the initial ASTM NDE standard by some NDE vendors, ASTM Subcommittee E07.11 members realized that "if we really wanted to see greater adoption, we'd have to make a greater effort to develop standards for specific modalities." Consequently, in 2008 the subcommittee completed E2663, Practice for Digital Imaging and Communications in Nondestructive Evaluation (DICONDE) for Ultrasonic Test Methods. This standard addresses metadata needed to describe ultrasonic inspection processes that do not apply to other NDE modalities.
In 2010, standards specific to three other testing modalities - digital radiography, computed radiography and X-ray computed tomography - were published. The standards are E2699, Practice for Digital Imaging and Communication in Nondestructive Evaluation (DICONDE) for Digital Radiographic (DR) Test Methods\; E2738, Practice for Digital Imaging and Communication Nondestructive Evaluation (DICONDE) for Computed Radiography (CR) Test Methods\; and E2767, Practice for Digital Imaging and Communication in Nondestructive Evaluation (DICONDE) for X-Ray Computed Tomography (CT) Test Methods.
Currently, ASTM Subcommittee E07.11 is working on a proposed new standard, WK33705, Practice for Digital Imaging and Communication in Nondestructive Evaluation (DICONDE) for Eddy Current Test Methods. The subcommittee is also investigating methods for testing the interoperability of different products following the DICONDE standard for data storage and communication.
Explains Rosenstock, who leads the E07.11 subcommittee's interoperability task group, "Whenever you develop standards, it's always important for users to have a test that ensures that the equipment they're buying does what they need it to do and that they can hold vendors accountable."
To date, according to Rosenstock, the NDE market is still moving toward acceptance of ASTME NDE standards with nearly all major NDE equipment manufacturers beginning to utilize them. Adoption of the standards is still widest in the area of digital radiographic testing, where the similarities between medical and industrial imaging are most pronounced. But, with rapid changes in technology accelerating the digitization of NDE methods and with critical national defense and commercial equipment and infrastructure continuing to mature, the understanding and acceptance of the need for standards addressing data exchange and storage methods is likely to grow.