Xenogen Releases 3D Software for its Proprietary Imaging Systems

Alameda, Calif., (May 16, 2005) - Xenogen Corporation (NASDAQ:XGEN) announced today the release of an advanced 3D software analysis package that enables researchers to better visualize, track and understand biological processes in living animals, non-invasively and in real time. The software is compatible with Xenogen's existing imaging systems and represents the first release in the Company's developing platform of 3D imaging capabilities.

Living Image Software 3D Analysis Package was designed for the IVIS Imaging System 3D, Xenogen' s latest advance in imaging technology, and to be compatible with the company's IVIS Imaging System 200 to provide more spatially accurate and quantitative data than the current software. Specifically, the software includes new tools that enable scientists to more accurately locate in three dimensions and quantify the signal strength of bioluminescent reporters, or glowing "tags" that light up targeted biological processes, in living animals.

The software introduces a 3D analysis method called DLIT that is the first of its kind for determining the location, size and brightness of the bioluminescent reporters and thus, creating a more spatially accurate image. DLIT processing takes place in two steps. First, a laser-scanned structured light image is acquired, which the software processes to determine the surface shape (or topography) of the animal. Second, a sequence of luminescent images is acquired through different light filters ranging in wavelength from 560 to 660 nanometers. Since the absorption of light in tissue is dependent on its wavelength, this spectrum or range helps spatially orient the location of the light source. Combined with the surface topography information, the software then analyzes and processes these images to determine the three-dimensional location and shape of the bioluminescent reporter.

"Xenogen's new Living Image Software 3D Analysis Package is a great addition to our portfolio because it improves upon the predictive quality of the data through enhanced localization of the light signal produced by our biophotonic imaging technology," said Pamela R. Contag, Ph.D., president of Xenogen Corporation. "Using the new software, scientists can better pinpoint the location of tumors, as well as the effect of drugs on a tumor and the surrounding tissue."Prior to release of this software, the location and strength of a reporter measured in IVIS imaging systems could only be done on a flat two-dimensional plane. With this software, Xenogen's IVIS Imaging System 200 instrument is now capable of generating single-view 3D mouse images; full three-dimensional reconstruction capabilities when using this software will be enabled with the upcoming IVIS 3D multiview imaging system.

Xenogen intends to introduce the IVIS 3D imaging system later this year. This is a completely new imaging system that will provide full three-dimensional (tomographic) analysis of bioluminescent reporters in mice. The new system will process multiple views and orientations taken around the mouse to provide researchers with better spatial representations of bioluminescent reporters such as cancer metastases and inflammatory markers. Information from this imaging system will be fully compatible with other current imaging modalities. Beta versions of this system have been installed at Stanford University (Stanford, Calif.), the University of Southern California (Los Angeles, Calif.), and the Sick Children's Hospital (Toronto, Ontario) for pre-clinical research.

"Biophotonic imaging technology is quickly becoming the new research standard in drug development, as illustrated though adoption by leading biotech and pharmaceutical companies," added Dr. Contag.

Xenogen holds exclusive patent rights to the essential methods for real-time in vivo biophotonic imaging. The company incorporates into microorganisms, cells and living animals the bioluminescent gene that makes a firefly glow, which it uses as a biological tag to see what's happening inside the animal (imaged with its IVIS Imaging System).

About Xenogen Corporation
Xenogen combines systems biology and low-light optical imaging to create powerful new biophotonic imaging technology that advances the ability of scientists to explore genes, proteins, pathogens and tumor cells in living animals in real time, providing predictive data that is designed to substantially improve the success rate in drug development. Xenogen incorporates into living animals the bioluminescent gene that makes a firefly glow and captures the resulting light using an ultra-sensitive camera and sophisticated software. This biophotonic imaging technology creates images and analyzes the data generated on cellular activity, gene expression, spread of disease or the effect of a new drug candidate. Xenogen's biophotonic imaging technology is used by leading academics and pharmaceutical and biotechnology companies to provide more accurate and previously unavailable data intended to result in the ability to make more timely and cost-effective decisions at every step in the drug development process.

Xenogen Biosciences, a wholly owned subsidiary of Xenogen, offers more than 14 years of experience in the transgenic field, providing reliable, genetically modified custom mouse models in short timelines. The company has completed more than 2,000 transgenic and 600 gene targeting experiments, with a greater than 95 percent success rate in delivering transgenic founder or gene knockout lines to customers.

More information about Xenogen is available on the company's Web site at www.xenogen.com. Xenogen, Living Image, IVIS and DLIT are registered trademarks or trademarks of Xenogen Corporation.