PREPRODUCTION INITIATIVE-NELP DIGITAL RADIOGRAPHIC SYSTEM (ORDNANCE APPLICATION) FINAL REPORT 1.0 INTRODUCTION NSWC INDIAN HEAD, MD The U.S. Navy has adopted a proactive and progressive position toward protecting the environment and complying with environmental laws and regulations. Rather than merely controlling and treating hazardous waste by end-of-the-pipe measures, the Navy has instituted a program for pollution prevention (P2) to reduce or eliminate the volume and toxicity of waste, air emissions, and effluent discharges. P2 allows the Navy to meet or exceed current and future regulatory mandates and to achieve Navy-established goals for reducing hazardous waste generation and toxic chemical usage. P2 measures are implemented in a manner that maintains or enhances Navy readiness. Additional benefits include increased operational efficiency, reduced costs, and increased worker safety. The Navy has truly set the standard for the procurement and implementation of P2 equipment. The Chief of Naval Operations (CNO), Environmental Protection, Safety, and Occupational Health Division (N45), established the P2 Equipment Program (PPEP), through which both the Naval Air Warfare Center Lakehurst (NAWCADLKE) and the Naval Facilities Engineering Service Center (NFESC) serve as procurement agents under the direction of N45. P2 equipment is specified and procured under two complementary initiatives: the Preproduction Initiative (i.e., technology demonstration) and the Competitive Procurement Initiative. The Preproduction Initiative directly supports both the Navy Environmental Leadership Program (NELP) for P2 shore applications and the P2 Afloat program, which prototypes and procures P2 equipment specific to the needs of ships. This report provides an analysis of the procurement, installation, and operation of P2 equipment under the Preproduction Initiative. Technology demonstrations and evaluations are primarily performed under NELP at two designated NELP sites Naval Air Station (NAS) North Island and Naval Station (NS) Mayport. Additional sites such as Naval Surface Warfare Center (NSWC) Indian Head have been added as required to meet specific mission goals. The program involves defining requirements, performing site surveys, procuring and installing equipment, training operators, and collecting data during an operational test period. The equipment is assessed for environmental benefits, labor and cost savings, and ability to interface with site operations.
2.0 BACKGROUND 2.1 Ordnance Inspection at NSWC Indian Head, MD The Naval Explosive Ordnance Disposal Technical Division (NAVEODTECHDIV) at NSWC Indian Head, MD, is responsible for the radiographic examination of explosive ordnance in support of the Department of Defense (DOD) Explosive Ordnance Disposal (EOD) program. NAVEODTECHDIV personnel use nondestructive inspection (NDI) techniques to examine ordnance before dismantling, disposing, or prescribing handling procedures. The site originally used standard radiography techniques (x-ray film) to examine ordnance. While the quality of the x-ray images was sufficient for the site s requirements, the standard radiography process uses hazardous materials, generates hazardous waste, and can be time-consuming. Types of hazardous materials used in the process include developers, fixers, and silver. Hazardous wastewater generated during the processing of x-ray film contains silver, a heavy metal that has a hazardous waste code of DO11. Maryland s Department of the Environment (MDE) authorizes silver recovery from contaminated process wastewater to avoid hazardous waste disposal fees. This end-ofpipe processing removes silver from the wastestream to less than the state s silver discharge limit of 5 ppm. The silver recovery process allows discharge of the treated wastewater into an approved sanitary system. In addition, site personnel often had to repeatedly x-ray the same piece of ordnance from different angles and distances to compensate for the object s varying densities and its intricate components. To reduce environmental hazards and costs, as well as to improve the ability of personnel to examine ordnance, a digital radiography system was recommended for evaluation. 2.2 Digital Radiography Technology Description Digital radiography was first implemented commercially in hospitals during the early 1980s. Recent advances in microprocessing performance have made systems smaller and more efficient. This prototype study explored the applicability of digital radiography to Navy ordnance inspection. When digital radiography is used to view an object, the variations in the object s features and density are mapped onto phosphor plates based on differences in radiation absorption. The digital radiography technique converts these differentials to differentials in phosphor plate ionization, storing the data in the phosphor material until the plate is excited by laser light. The light causes the phosphor to luminesce, displaying a latent image that is collected by a light guide and subsequently displayed on a computer workstation. From this workstation, the image can be transferred and thermally printed by a laser printer onto digital radiography film. Digital radiography film is similar to conventional x-ray film in size, appearance, and ability to be viewed through backlighting; however, it contains no silver.
Phosphor imaging plates replace the traditional method of wet chemistry film processing. These imaging plates are composed of phosphors that are sensitive to various forms of radiation. They store energy produced during exposure and produce a latent image by transferring the energy from the impinging radiation to the phosphor crystals. The energy is released to create an actual image, which is then digitized by a platereading device. One of the key advantages of digital radiography is its ability to use several features that allow electronic data storage, retrieval, enhancement, and transfer. During the scanning/ reading operation of the image plate, a digital file is created. This original scanned image is write-protected by the system and cannot be altered. The system allows only displayed changes (e.g., intensities, changes to the gray scale, contrasts, densities, etc.), which are referred to as manipulations. The file is then transferred and archived on an optical disk, or it can be reviewed and manipulated on a computer workstation. Files can be easily transferred electronically, enabling multiple personnel to view and access the image file. Also, phosphor image plates can record more information than film, allowing greater indepth analysis and manipulation of an image. This saves labor time and reduces hazardous material usage because conventional radiography usually requires that multiple shots be taken of the same object. In addition, replacing film with phosphor imaging plates eliminates the hazardous materials and hazardous waste associated with film development. Furthermore, consumables are minimized because the image plate can be used numerous times and can flex around the shape of the object. Finally, worker exposure to x-rays is decreased since fewer shots are required and phosphor image plates require considerably less radiation than conventional radiography. 3.0 EQUIPMENT DESCRIPTION 3.1 Vendor Selection During the equipment selection period, there were two primary vendors with systems on the market, Fuji and Liberty Technologies. The Fuji system contains features that produce a higher quality image and allow greater latitude in exposure times; therefore, it was chosen rather than the Liberty Technologies equipment. Also, the Air Force had been studying the Liberty unit as a replacement for conventional radiography used in the NDI of aircraft parts. It was determined that, by procuring the Fuji equipment, the Navy and Air Force could exchange information about the operability and success of each vendor s equipment.
3.2 Fuji Digital Radiography System and Virtual Media Integration The Fuji Digital Radiography System and Virtual Media Integration (VMI) equipment and software have been integrated to provide one compatible system that allows the widespread use of digital radiography. Fuji hardware allows the digital imaging system to read/scan the images from phosphor imaging plates and display the images on a computer workstation; VMI software allows the images to be enhanced and transmitted electronically. Fuji and VMI have provided the site with the following components: Fuji Digital Radiography System AC-3 image plate reader/erasure unit Image plates and cassettes HI-C654 workstation to display images; hard-copy capability and system image storage capability with VMI-STARR software Laser printer Calzone enclosures for transportation Virtual Media Integration STARR software, which enhances the digital images and is compatible with VMI radiographic scanning digitizers 3.2.1 Fuji Digital Radiography AC-3 Image Plate Reader/Erasure Unit The AC-3 Image Plate Reader/Erasure Unit is the main component of Fuji s hardware system. It is a data entry terminal that enables inspection personnel to select various read routines. Digital enhancements are applied to the image data as it is being extracted and compiled. Data entry is accomplished by employing a programmable menu drive, manual keyboard and/or magnetic card reader, all of which are provided as part of this input device. Constant density enables image files to be displayed at preselected gray-scale levels, regardless of exposure parameters (constant density control). The AC-3 provides many features and advantages: Image data is computer-processed, which produces workable images for inspection. Automatic density adjustment and the wide dynamic range of the imaging plate provide high-quality images, resulting in fewer reshots. The system s high sensitivity allows for a significant reduction in exposure time. Digitized image data provide many benefits, including image transmission, manipulation, enhancement, and storage. Easy operation of the system allows for greater consistency by users.
3.2.2 The Fuji Digital Radiography CRT Image Console HI-C654 Fuji s HI-C654 Image Console displays images on a high-resolution, 21-inch monitor and can provide additional image processing capabilities, if necessary. The HI-C654 has a proprietary operating system. The images can be displayed or printed individually or two, three or four to a screen, which allows faster inspection and an increased confidence level. The HI-C654 workstation provides the following features and advantages: High-quality images are produced on the high resolution CRT monitor. The HI-C654 automatically stores incoming images on its built-in hard disk for quicker retrieval of individual images. Images from the Fuji system are written to the hard disk in a way that allows for uninterrupted processing of currently displayed data. This allows the user to manipulate images while the newest images become available. Images with tonal, magnification, and/or spatial frequency modifications may be printed as hard copies on digital radiography film. 3.2.3 Virtual Media Integration, STARR Software The VMI software package, called STARR, has been integrated and is compatible with the Fuji system. It can convert and compress existing image files for transmission electronically, and makes the file compatible with most computers so the recipient can view the image file without special software. The STARR software converts a 10-bit Fuji image to a TIFF or other 8-bit file format, thereby facilitating communications protocol and recordkeeping. The STARR software includes the following features and advantages: STARR software eliminates the use of film, and allows the image files to be accessed more readily and sent electronically to multiple personnel. Converting from the Fuji format to the STARR program increases accuracy, allows more images to be read, and reduces the time it takes to evaluate these images. Image enhancement includes: image threshold, contrast/brightness stretching, image rotation 90 degrees, image flip and mirror image crop, image pan and scowl, image zoom up to pixel resolution, image annotation, the ability to display density values along a line at arbitrary angles, measure distance between any two arbitrary chosen points with the measured distance remaining unchanged during zoom or minimize, the ability to measure area as a function of density, histogram masking, high pass, low pass and median filtration, magnification, and a floating magnification glass. Customizable image processing kernels of 3 x 3, 5 x 5, 7 x 7, 9 x 9 sizing allows for varied edge enhancement and other kernels, positive/negative switching, false color, and true optical density with varied backlighting colors. The system has densitometer functions, density graphing, histogram functions within a region of interest, and the ability to compress files and export images.
3.3 Implementation Requirements 3.3.1 AC-3 Image Plate/Erasure Unit Dimensions (W x D x H): 27-15/16 x 26-13/16 x 41-1/8 Weight: 81.7 lb. Electrical: 110V outlet AC 50/60Hz 1kVA Capable of processing 70 to 90 imaging plates per hour, depending on the size of the imaging plate. 3.3.2 Imaging Plates and Cassette Imaging plates are flexible and reusable. Standard type imaging plates come in four standard sizes: 14 x 17, 14 x 14, 10 x 12, and 8 x 10. A high image quality (HQ) plate is available in sizes 14 x 17 and 8 x 10. Image plate feed and load time is approximately 50 seconds. 3.3.3 HI-C654 Workstation Hard-Copy Capability The laser printing device uses a transparent recording media similar in appearance to x-ray film. The hard copy technology is dry (uses no wet chemistry and does not produce effluent waste). Laser copies are thermally processed with typical spatial resolution of 2K x 2K pixels/screen. The user can select the printing format, which is available in either single or multiple images per hard copy. 3.3.4 Calzone Case Fuji specifically designed the calzone cases for NAVEODTECHDIV at NSWC Indian Head, MD. They are used to transport and ship the Fuji AC-3 system, video display, and imaging plate. Also, the calzone provides portability by allowing technicians to transport the Fuji AC-3 digital radiography system to a site when performing ordnance inspections. The process of shooting, scanning/reading, and manipulating a shot onsite with the Fuji digital radiography system provides convenience and no wasted time for the technicians. The calzone cases are an additional item and are not always needed when purchasing a digital radiography system; however, they provide needed high-impact protection if the system is required to be portable. 3.3.5 VMI Workstation - System Image Storage Capability This technology uses a SCSI interface to enable the Fuji images to be displayed and
stored on a PC platform. Its subassemblies include: DASM: SCSI interface with communications port Pentium 166 PC platform with 32-MHz RAM, 2.1-GB hard drive, CD-ROM burner, reader and jazz drive for digital tape STARR software to enhance and digitally process images exported from digital radiography image files. STARR software is compatible with VMI radiographic scanning digitizers. 3.4 Benefits 3.4.1 Technical Benefits Imaging plates have a wide dynamic range and a linear exposure response, which means that one exposure covers a wide range of part thicknesses while maintaining target densities. Automatic density controls compensate for either overexposure or underexposure. Images are stored on disks so they can be quickly retrieved and reviewed. Radiographic data stored on a disk is preserved indefinitely. Minimal archival storage space is required. Digital radiography expands viewable density range by 3 to 4 times over conventional film. Imaging plates can be reused, thereby eliminating the costs associated with conventional film. Images can be electronically transferred to remote viewing sites for instant consultation and analysis. Radiation safety concerns are reduced because a smaller dose is required. Environmental concerns associated with film processing are eliminated, including the discharge of silver and other spent hazardous photographic chemicals. Image analysis is improved by reducing interpreter subjectivity. 3.4.2 Environmental and Cost Benefits The Fuji system and VMI equipment provide several benefits when compared to conventional radiography, including: Eliminates film processing chemicals and hazardous wastes and materials. Reduces the cost of hazardous waste disposal. Eliminates the need to perform silver recovery processing. Eliminates precleaning of the film developing machine. Eliminates the requirement for procurement of x-ray film. Provides a healthier work environment/reduced exposure to radiation. Reduces labor hours required for weapons inspection. Expands the capabilities of weapons disarmament field personnel. Facilitates the electronic transfer of images from the field or between experts for
consultation and analysis. Eliminates reshooting multiple exposures by allowing electronic manipulation of the images. 4.0 DATA ANALYSIS 4.1 Quantitative Analysis Compared to the traditional wet chemistry process, the Fuji system has a 10-year return on investment (ROI) of $1,432,746.90 per unit, with a break-even point of 1.89 years (refer to the Cost Analysis for complete data). 4.2 Qualitative Analysis 4.2.1 Installation Installation occurred without any significant difficulties. The Fuji AC-3 system was operational within 2 ½ hours. Some minor hardware problems were quickly corrected by the vendor. These problems had no bearing on the newly installed equipment. To date, no problems have been reported. 4.2.2 Training Training took place in two phases. During Phase I, NAVEODTECHDIV personnel were given a 1½-day tutorial on the basics of the system. Personnel were able to use the unit after less than one day of training. Next, the system operated for a month so personnel could become more familiar with system capabilities before the Phase II training. By the end of the second phase of training, site personnel were using the advanced features and were proficient with all system functions. 4.2.3 Maintainability The unit has experienced no problems with maintainability and has not required repairs. Standard maintenance consists of a basic preventive maintenance program. Fuji has a strong customer support program with a toll-free number for users to call if any problems arise. Troubleshooting advice is given over the phone and, if repair is required, a Fuji technician can usually be onsite within one day.
4.2.4 Interface with Site Operations The site readily and eagerly integrated the equipment into its procedures. During initial testing of the unit, both traditional wet chemistry and digital radiographic methods were used and the results were compared. Eventually, the workers switched solely to digital radiography in the interest of saving time and because there was no longer a need for redundant testing. Site personnel judged the quality of digital radiograph images to be better than or equal to the x-ray film images. 4.2.5 Overall Performance The Fuji and VMI equipment has performed very well. The digital radiography process required less time during the developing and manipulation stages than traditional wet chemistry photo processing. The developing stage of digital radiography can be described as scanning the exposed image plate and downloading the image into the Fuji AC-3. During the manipulation stage, the original scanned image is saved on the hard drive of the computer and cannot be changed. This image can then be manipulated on the computer workstation until an acceptable image is present onscreen. Developing time was reduced from 15 minutes to 1 minute, a 93.3% reduction, and manipulating the object was reduced from 60 minutes to 4 minutes, also a 93.3% reduction. Digital radiography requires no chemicals when developing the image, while traditional wet chemistry does. Often, objects that were difficult to x-ray and which required multiple shots required only one exposure with the digital radiographic equipment. Some advantages realized by the Fuji system included: Scan time of approximately 45 seconds. Ability to scan and erase the phosphor plate in one operation. Minimum amount of equipment; only three major components (scanner, laser printer, and computer workstation). Fixed scan rate of 75 microns. Ability to preprogram specific inspection parameters. These advantages allowed the maximum performance of the Fuji system. The system s capabilities proved to be superior to any conventional x-ray method. 4.2.6 Future Uses Possible additional sites for the digital radiographic system within the ordnance inspection area include, but are not limited to: NSWC Yorktown, VA; NSWC Concord, CA; NSWC China Lake, CA; NSWC Crane, IN. The sites listed are not prioritized in any specific order. The digital radiographic system has proven its success and has the potential to be used at many other Navy facilities.
5.0 LESSONS LEARNED Because of the classified nature of much NAVEODTECHDIV work, three removable hard drives for the equipment are recommended. For operations where sensitive material is x-rayed, security must be programmed into the system to ensure that unauthorized personnel cannot read classified files. The VMI system has capabilities that limited its performance at the time the software was offered to NSWC Indian Head. Initially, NSWC Indian Head received an early version of the software. Today, VMI s software is fully compatible with the Fuji System. VMI also offers upgrades to its STARR software for registered users. Any new developments of the software will be offered in the future. The software package and upgrades can be downloaded from VMI s website. 6.0 CONCLUSIONS Digital radiography is an excellent alternative/replacement to conventional radiography. Its advantages outweigh those of standard x-ray procedures as described in Sections 3.2 and 3.4. When digital radiography was implemented into the daily routine at NSWC Indian Head, MD, it proved to make radiography an easier process. By providing a sideby-side comparison of the conventional radiography and digital radiography, NSWC radiologists were able to compare data and agree to the success of the test period. It was proven that digital radiography not only saves time and money, but also that the technology is superior to conventional methods.