Palo Alto, Calif. - June 5, 2003 - Varian Medical Systems, Inc. (NYSE:VAR) hasreceived 510(k) clearance from the U.S. Food and Drug Administration (FDA) to market a new version of its VariSeed™ treatment planning software for permanent seed implant brachytherapy, used in treating prostate cancer. VariSeed 7.1 offers physicians new imaging and editing tools designed to improve and speed intra-operative treatment planning, so patients spend less time in the operating room. VariSeed facilitates dynamic dosimetry and real-time treatment planning. The program enables clinicians to use anatomical images to create an interactive and personalized treatment plan in the operating room during an implant procedure. VariSeed 7.1 incorporates a new, optional Twister™ longitudinal volume acquisition module that enables doctors to use ultrasound images of the prostate that have been taken without repositioning the probea process that can disturb or distort the prostate and yield inaccurate images. The Twister function in VariSeed 7.1 thus enables clinicians to acquire more accurate images in less time. They can position and rotate the ultrasound probe once to acquire an image of the full volume of the prostate in the longitudinal view. "With a single twist, physicians can acquire all the image data they need for treatment planning," said Dave Hall, brachytherapy product manager with Varian Medical Systems. “This eliminates the need for a multi-step process that involves repositioning the probe repeatedly to obtain the volumetric image data. With a better view of the prostate, physicians can improve the quality of the implants patients receive." VariSeed 7.1 also features a new “Needle Editor.” This permits a doctor to visualize planned seed placements within the prostate volume, and then to interactively move, add, or delete seed placements and observe how the dose distribution will be affected, before using needles to place the seeds within the patient's prostate. "Both of these new tools cut down on the amount of time it takes to generate a useable treatment plan," explained Ted Jackson, PhD, chief developer of the VariSeed software. "VariSeed is largely geared toward intra-operative planning, so we want to reduce the amount of time it takes to create the treatment plan as much as possible." Permanent seed implants for prostate cancer have become more common in recent years. The procedure is completed in a few hours, and according to research published in the Journal of the American Medical Association, results are comparable to radical prostatectomy, with a lower risk of side effects like impotence and incontinence. The American Cancer Society has predicted that over 200,000 men in the U.S. will be diagnosed with prostate cancer in 2003. The popularity of permanent seed implants as a treatment option has risen rapidly; the technique was virtually unused ten years ago and is now chosen by over 60,000 men annually, according to data presented at the Sixth Annual Advanced Prostate Brachytherapy Conference in Seattle during April, 2003. VariSeed 7.1 is available to new customers and as a software upgrade to clinics that already use prior versions of VariSeed for planning and documenting prostate seed implant dosimetry. VariSeed brachytherapy treatment planning software is the leading product in its category, with about 800 workstations installed worldwide. Varian Medical Systems’ BrachyTherapy division also produces the VariSource™ and GammaMed™ Afterloaders for delivering HDR brachytherapy. For more information about VariSeed 7.1 treatment planning software from Varian Medical Systems, call 1-888-666-7847 ext. 240.