Clinical Data on IsoRay Medical's Cesium-131 to be Presented at the 28th American Brachytherapy Society Annual Meeting.

RICHLAND, Wash. -- New information about the safety and efficacy of IsoRay Medical's Cesium-131 brachytherapy seeds will be presented at the American Brachytherapy Society's (ABS) 28th Annual Meeting to be held April 29th though May 1st, 2007 in Chicago, Illinois. Four submissions from key opinion leaders in the brachytherapy market will provide highly sought after information regarding Cesium-131 brachytherapy seeds.

Brad Prestidge, M.D. and William Bice, PhD of the Texas Cancer Clinic will be presenting two papers that contain preliminary results in 80 patients from the IsoRay Medical Inc., multi-institutional monotherapy trial. These presentations will provide important characteristics of Cesium-131 brachytherapy seeds such as post-implant radiologic outcomes known as "dosimetry" and the correlation of those outcomes to near-term side effects and quality of life for patients receiving Cesium-131 permanent brachytherapy implants. In addition, preliminary information regarding severity and time to resolution of common side effects will also be presented and compared against Iodine-125.

Brian Moran, MD of the Chicago Prostate Cancer Center will also be presenting on his early findings with Cesium-131 specifically focusing on prostate specific antigen (PSA) response as well as short term adverse events. This will be the first release of information regarding PSA response to Cesium-131 brachytherapy seeds. Changes in PSA is a key measure physicians use to access response to treatment.

World renowned medical physicist Mark Rivard PhD has also had his paper on the dosimetric parameters of Cesium-131 accepted for publication at the 2007 ABS Annual Meeting. The information in this paper will confirm critical dosing information for Cesium-131 that providers and dosimetrists use when planning an implant.

The brachytherapy community can expect to see more data come available this year on Cesium-131 as on-going results from IsoRay's large-scale, multi-institutional monotherapy study accrues and matures. A combination therapy protocol using Cesium-131 in combination with external beam therapy was also initiated in the first quarter of 2006. This will be IsoRay's second multi-institutional study and will be looking at the short and long term clinical outcomes of combined therapy in intermediate to high risk patients. Preliminary data from this trial could emerge as early as late in 2008 and provide valuable information for physician treating higher risk patients. Based on these and other studies currently in negotiations, IsoRay Inc. expects to have a solid base of compelling evidence comparing Cesium-131 to the other leading isotopes in efficacy and tolerability that will establish Cesium-131's position in the market.

About IsoRay

IsoRay, Inc. ("IsoRay") (OTCBB:ISRY) through its subsidiary, IsoRay Medical, Inc., is the sole producer of the Cesium-131 brachytherapy seed, used to treat prostate and other cancers. The cesium-131 seed offers a significantly shorter half-life than the two other isotopes commonly used for brachytherapy, which results in a substantially faster delivery of therapeutic radiation and lower probability of cancer cell survival. IsoRay is based in Richland, Washington. More information is available about IsoRay at www.isoray.com.