Stellarray, a Texas C corporation, was spun out of SMD in late 2007 to bring flat panel radiation sources to market. The basic technology was developed in an SMD project on X-ray and UV/C sources for the Air Force Research Laboratory to safely and rapidly decontaminate biohazards such as anthrax. This project ended with successful alpha (laboratory) prototypes of both sources. We are now working with support from the NIST Advanced Technology Program to develop beta prototypes of the X-ray panels in increasingly large sizes. We will start selling development kits to OEM partners in late 2009, with full-scale production in Austin starting in 2010. Stellarray shares facilities and some staff with SMD.

All of the panel products in Stellarray¡¦s portfolio will use the same basic cold cathode array processes. These provide the innovative shift from point sources, such as X-ray tubes or UV lamps, to panel sources, for major advantages in our target markets. UV radiation panels are made by hitting phosphors with electron beams. The X-ray panels use electron beams from cold cathode arrays fabricated on one side of the panel to strike a metal target (anode) on the opposite side; the X-rays then exit out past the cathodes. If all the cathodes are turned on at once, X-rays emit from the entire panel area, for a plain flat panel X-ray source, or FPXS. In a digitally addressable X-ray source, or DAXS, small groups of cathodes are addressed at specific locations on the panel to make ¡匣-ray pixels¡¨. The X-ray panels can be made in small sizes, e.g. 5¡¨ on a side, on up to 20¡¨ or more using processes from the flat panel display industry.

UV Panels

These will look like double-paned windows, but emit different wavelengths of UV-C light, depending on the phosphor. Our partners at the Georgia Tech Research Institute developed the phosphors used in the Air Force decontamination project (¡你nthrax killer does its work with no muss, no fuss¡¨). Stellarray¡¦s UV-C panels will solve several problems with UV lamp technology by eliminating hazardous mercury and improving efficiency in a compact, safe, easy-to-clean glass panel format that can be used as a structural component. Panels with other UV wavelengths will be used in industrial processes, such as curing epoxies, and in photolithography.

Flat Panel X-ray Sources (unpixilated)

The first major application of these panels will be to sterilize medical products as they leave the factory and to sterilize blood supplies. Later applications will include sterilization of hospital waste fluids, mail and food. Medical products need to be sterilized in their packages, which in most cases requires penetrating radiation such as X-rays. Current sterilization facilities use high-energy X-rays produced with high-energy electrical sources such as linear accelerators, or, more commonly, gamma rays from radioactive isotopes. These facilities require massive concrete walls for radiation shielding, making them costly and centralized. Conveyor belt sterilization systems using FPXS panels will use lower, safer energies, be largely self-shielding, reduce capital and operating costs by 90%, and bring sterilization close to the point of production. More urgently, a report of the National Academy of Sciences highlights the security risks of isotope sources, which can be used in ¡吳irty bombs¡¨, and recommends their selective replacement. We are working with the National Sterilization Research Center at Texas A & M University to develop FPXS conveyor systems. Other applications include an X-ray autoclave to replace inefficient steam systems in hospitals and several types of biohazard decontamination systems. FPXS panels will later be used in industrial and scientific systems, where they can be programmed to cover specific areas and are easier to collimate. This will also help airport and other X-ray scanner OEMs make their systems more compact, efficient and sensitive.

Digitally Addressable X-ray Sources (pixilated)

These panels will also be used in several market segments, mainly in medical imaging, where they will replace huge, expensive and performance-limiting mechanical gantries with digital addressing of X-ray pixels in systems with no moving parts. DAXS addressing will also allow the precise shaping and placement of X-ray beams, with intensity modulation using imaging feedback controls to lower radiation doses, the degree of reduction depending on the application. We are working with the Digital Imaging Research Lab at the MD Anderson Cancer Center on digital tomosynthesis for breast cancer screening with much higher accuracies than current mammograms due to the ability to better resolve overlapping tissues. Later non-contact mammography systems will use strips of DAXS sources and electronic detectors. In cardiac CT, current systems can¡¦t move a mechanical gantry fast enough to keep up with the beating heart, resulting in unclear images. Electronic addressing of X-ray pixels in the DAXS will provide clear images without the use of beta blockers. DAXS panels can be combined with flat panel detectors for portable CT for battlefield and emergency medicine, and in emerging markets. These systems will be developed with OEM partners and will require clinical trials for patient safety, verification of image data and quantification of system benefits. An earlier application will be a small animal imaging system (¡吮ouse CT¡¨) built with university partners for cancer and drug research. This has become very important with the recent mapping of the mouse genome. Current mechanical systems are very expensive and still can¡¦t provide clear images since the mouse heart has over 500 beats per minute. Our system will cost substantially less and have no trouble keeping up with mice. Other DAXS applications will include security and industrial imaging systems and radiation therapy.

For more information, please check back here or contact eaton@stellar-micro.com

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