LONG BEACH, Calif., May 22 -- Several groups are presenting new T-ray research at CLEO, including researchers from Germany who developed a system that could lead to marker-free methods for biomedical imaging, and a group from Rensselaer Polytechnic Institute (RPI) who demonstrate the possibility that T-rays could be used to screen mail for Anthrax spores. T-rays are the electromagnetic waves, also known as Terahertz (THz) radiation, with frequencies between microwave radiation and infrared light, and are on the cutting edge of new imaging technologies that could one day replace x-rays in some imaging applications. Thomas Kleine-Ostmann and his colleagues in Martin Koch's research group at Technische Universitat Braunschweig in Germany have created the first imaging system using a continuous-wave THz radiation. They said the system is more compact and cost-effective than current systems using pulsed T-rays, and it does not require a laboratory environment. At RPI's Center for THz Research, Shaohong Wang and his colleagues in Prof. Xi-Cheng Zhang's THz Group used T-rays to examine powder inside envelopes. Many packaging materials are transparent to T-rays, making them ideal for use in nondestructive mail screening. Using Bacillus thurengiensis bacteria spores, the researchers were able to use T-rays to image bacterial spores inside an envelope.