IsoRay Announces World’s First Cesium-131 Colon Cancer Treatment at Cornell Medical Center

RICHLAND, Wash.--(EON: Enhanced Online News)--IsoRay, Inc. (AMEX:ISR), announced today that on October 10, 2009, Dr. Bhupesh Parashar, Dr. A Gabriella Wernicke and Dr. KS Clifford Chao from the Department of Radiation Oncology, and Dr. Jeffery Milsom from the Department of Gastrointestinal Surgery, at Weill Cornell Medical Center performed the world’s first Cesium-131(Cs-131) implant for the treatment of colorectal cancer.

“The patient tolerated the procedure well and had no evidence of cancer recurrence or any side effects that can be attributed to the Cesium-131 seed implant at the last follow-up visit.”

This implant was performed on a 38-year-old patient with locally recurrent colon cancer who underwent surgical resection of the tumor as a part of the treatment. The patient has a history of multiple prior surgeries and chemotherapy for colorectal cancer.

Dr. Parashar stated, “The patient tolerated the procedure well and had no evidence of cancer recurrence or any side effects that can be attributed to the Cesium-131 seed implant at the last follow-up visit.”

Cesium-131 was chosen for its short half-life and higher dose rate. In addition, the Cs-131 seed brachytherapy procedure has the advantage of relative safety to the medical staff (because of faster radioactive dose fall-off) if the patient requires additional medical care soon after the implant.

Cesium-131 is now being used successfully to treat lung, head and neck, ocular melanoma, and prostate cancers in other patients. In doing so, Cs-131 is expanding brachytherapy options for patients beyond the prostate to locally recurrent cancers in many areas of the body.

Dwight Babcock, IsoRay's CEO, stated, “In 2009, we made significant advancements in our strategy to provide Cesium-131 brachytherapy treatment to physicians to use in their arsenal of tools for fighting cancers throughout the body. We continue to build on that strategy in early 2010 by opening a lung study and moving forward with our preparations to expand the use of Cs-131 to additional areas in the body. We believe brachytherapy using Cs-131 has a unique and growing application to many areas within the body - not just the prostate.”

About IsoRay

IsoRay, Inc., through its subsidiary, IsoRay Medical, Inc., is the sole producer of the Cesium-131 brachytherapy seed.

The Cesium-131 seed offers a significantly shorter radiation half-life than the two other isotopes commonly used for brachytherapy, which results in a substantially faster delivery of therapeutic radiation, a theoretically improved radiation delivery against aggressively replicating cancer(a), and the potential for a reduced longevity of common brachytherapy side effects(b).

Cesium-131 is currently used in the treatment of prostate cancer(c) and ocular melanoma(d), and now available for lung, head and neck and colon cancers.

IsoRay is based in Richland, Washington. More information is available about IsoRay at www.isoray.com.

(a) Armpilia CI, Dale RG, Coles IP, et al. The Determination of Radiobiologically Optimized Half-lives for Radionuclides Used in Permanent Brachytherapy Implants. International Journal of Radiation Oncology, Biology, and Physics 2003;55(2):378-385.

(b) DeFoe SG, Beriwal S, Smith R, Benoit R. Is there decreased duration of acute urinary and bowel symptoms after prostate brachytherapy with cesium 131 isotope? International Journal of Radiation Oncology, Biology, and Physics 2008;72(S1):S317.

(c) Bice WS, Prestidge BR, Kurtzman SM, Beriwal S, Moran BJ, Patel RR, Rivard, MJ. Recommendations for permanent prostate brachytherapy with (131)Cs: a consensus report from the cesium advisory group. Brachytherapy 2008;7(4):290-6.

(d) Melhus CS, Rivard MJ. COMS eye plaque brachytherapy dosimetry simulations for 103Pd, 125I, and 131Cs. Medical Physics 2008;35(7):3364-71.

Safe Harbor Statement

Statements in this news release about IsoRay's future expectations, including: the advantages of our Proxcelan Cesium-131 seed, whether IsoRay will be able to expand its base beyond prostate cancer, whether IsoRay's Cesium-131 seed will be used to treat additional cancers and malignant disease, whether the use of Cesium-131 to treat colon, lung or other cancers will be successful in the initial and any future implants, whether a clinical trial for lung cancers will be completed, and all other statements in this release, other than historical facts, are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 ("PSLRA"). This statement is included for the express purpose of availing IsoRay, Inc., of the protections of the safe harbor provisions of the PSLRA. It is important to note that actual results and ultimate corporate actions could differ materially from those in such forward-looking statements based on such factors as physician acceptance, training and use of our products, our ability to successfully manufacture, market and sell our products, our ability to manufacture our products in sufficient quantities to meet demand within required delivery time periods while meeting our quality control standards, our ability to enforce our intellectual property rights, whether additional studies are released and support the conclusions of early clinical studies, whether initial implants of Cesium-131 to treat colon, lung or other cancers result in favorable patient outcomes, whether resources are available as needed to conduct a clinical trial for lung cancers and whether results of any such trial are favorable, patient results achieved when Cesium-131 is used for the treatment of cancers and malignant diseases beyond prostate cancer, successful completion of future research and development activities, and other risks detailed from time to time in IsoRay's reports filed with the SEC.