NASA Computer Imaging Technology Is Helping Commercial Firm See New Jobs And More Profits

Bio-Imaging Research, Inc., (BIR) of Lincolnshire, Ill., is seeing new employees in its plant and more profits at the end of the year, all thanks to their commercializing computer imaging technologies developed for NASA's Marshall Space Flight Center in Huntsville, Ala.

The Advanced Computed Tomography Inspection System (ACTIS) was put into service at Marshall in 1989 to find imperfections in aerospace structures and components such as rocket motor casings, assemblies and nozzles used in the Space Shuttle program. ACTIS helped NASA engineers characterize structural assemblies by producing high-quality computed tomography (CT) images. These images demonstrated the ablative properties of various solid rocket motor nozzle assembly materials and revealed anomalies at bondline interfaces that could have caused mission failures. The two-million-volt ACTIS system at Marshall has also found flaws in turbine and valve castings for NASA.

Having proven its potential in the national space program, the system was used to scan an entire automobile, as well as large castings used in the automotive industry. It has scanned a cruise missile's jet engine. A similar ACTIS at Boeing has scanned a complete satellite, avoiding the time and expense of opening it, then resealing and resterilizing it. It has also verified the safety of spaceborne battery packs.

BIR undertook to refine the technology for broader commercial applications, introducing a smaller, PC-based version called ACTIS+ for general industrial use. BIR spokesman Charles Smith said recently, "ACTIS+ provides CT imaging capability at less than a third the cost of current CT systems."

CT itself is a technology derived partly from the Apollo space program of the 1960's and partly from the field of medicine. CT creates cross-sectional images by projecting a thin beam of x-rays through one plane of an object from many different angles. In some scanners, a cone beam covers an area detector so that many slices or a volume can be scanned at once.

Millions of people around the world benefit each year from the medical applications of the technology. Hospitals use CT scanners to help diagnose illnesses and assess injuries. The technology also was quickly adopted by industries for non-destructive testing.

The key to the low cost of ACTIS+ is that it is designed to be added to existing real-time radiography (RTR) systems. It uses major RTR components and can eliminate the expense of an x-ray system and a detector system.

The ACTIS+ system consists of a high-precision rotation/elevation manipulator, a color image monitor, a graphical user interface monitor, a keyboard with mouse, and a Unix-based PC compatible workstation. "From our viewpoint," Smith says, "one of the most important commercial applications of the technology came when Marshall allowed us to scan a 55-gallon drum containing cement, metal parts, liquids, and other materials. This allowed us to demonstrate to the U.S. Department of Energy (DOE) that computed tomography is much better at seeing what is inside drums of radioactive waste than any existing techniques."

The tests at Marshall led to the development of Waste Inspection Tomography (WIT), a trailer-mounted portable system that can be taken to waste dump sites to identify the contents in drums found there. "We have written software that enables us to combine three-dimensional x-ray CT images of the drum's contents with three-dimensional gamma-ray information on where the radioactivity is inside the drum. To our knowledge," said Richard Bernardi, program manager for WIT, "this is the only non-medical application that presents two different types of sensor information in a single picture. BIR has gone even further by adding a third sensor that provides information on the distribution of neutron emitters, such as plutonium, into the three-dimensional image."

The main sensor in the WIT trailer is a two-million-volt CT system. The voltage is able to see through drums filled with high-density material, such as cement or sludge, which cannot be penetrated by other x-ray systems used by the DOE. While the scanner can provide "quick look" images, its primary value is in making volume CT images comprised of more than 75 individual slices. Two gamma cameras image the internal radioactivity and their output can be presented in either two- or three-dimensional form. Special software allows their images to be accurately superimposed on the density images from the CT scanner. The radioactivity is measured by nuclear spectroscopy, which determines its gamma-ray energies and then looks up that energy in a table to identify individual isotopes. The system can distinguish between weak internal sources surrounded by low-density material and a shielded stronger source.

It can also identify and measure the volume of potentially corrosive free liquids, the extent to which the storage drum's wall may have been thinned by corrosion, and the presence of objects that are supposed to be forbidden in storage drums. BIR has been able to integrate the results of a neutron-sensing system developed by Lockheed-Martin's Pinellas, Fla., facility, and superimpose the spatial distribution of neutron intensities onto the three-dimensional x-ray density information. Bernardi said the mobile device has performed outstandingly at a number of DOE sites. The device is back at BIR's facility. BIR hopes to increase the number of detectors on the unit to scan drums from five to 30 times faster. BIR hopes to build two additional trailers so as to be able to offer scanning and other analytic services to DOE and to nuclear power utilities that are a significant source of radioactive waste.

Dr. John F. Moore, president of BIR, pointed out that the technology developed for NASA has led to other products. BIR has adapted the detectors to keep their efficiency with x-ray energies as high as nine million volts, and have installed a six-meter-high linear detector array to inspect tractor-trailers for contraband at the border crossings near Shenzhen in the People's Republic of China. Systems now in use by the U.S. Customs Service operate at 450,000 volts and - while able to see false compartments in the outer walls of vehicles - they cannot look through heavily loaded cargo as well as the system in use by the Chinese, he said. For more information on BIR, contact Smith at 425 Barclay Blvd., Lincolnshire, IL 60069-3624 or phone (847) 634-6425.