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1. www.isoray.com Pioneering Internal Radiation Therapy with Cesium131 v092911

2. Forward Looking Statements This presentation contains forward-looking statements. These statements relate to future events or our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our or our industry’s actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed, implied or inferred by these forward-looking statements. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “should,” “could,” “would,” “expects,” “plans,” “intends,” “anticipates,” “believes,” “estimates,” “predicts,” “projects,” “potential” or “continue” or the negative of such terms and other comparable terminology. These statements are only predictions based on our current expectations and projections about future events. You should not place undue reliance on these statements. Actual events or results may differ materially. In evaluating these statements, you should specifically consider various factors, including the risks outlined under “Risk Factors” in our Annual Report on Form 10-K filed with the SEC on September 28, 2011. These and other factors may cause our actual results to differ materially from any forward-looking statement. We undertake no obligation to update any of the forward-looking statements after the date of this presentation to conform those statements to reflect the occurrence of unanticipated events, except as required by applicable law.

3. Corporate Highlights • Emerging market leader for internal radiation therapy of cancer • Based on exclusive patents for a proprietary separation process for the Cesium131 isotope • Lead products launched and markets growing • FDA cleared for use in all body sites and tumor types • A superior solution for brachytherapy of cancer • Cesium131 products offer safe and effective results compared with: • external radiation and surgery • internal radiation therapy with other isotopes • Multiple cancer indications in US and EU markets • Current: Prostate, Lung, Brain, Head/Neck, Ocular, Colon and Gyn • Pipeline: Breast, Esophageal, Pancreatic • Additional market expansion in combination with various existing delivery methods and devices • New GliaSite® product line for treatment of brain cancer

4. A Better Solution • Dr. DattatreyuduNori, professor of clinical radiology at Weill Medical College of Cornell University and radiation oncologist-in-chief at New York-Presbyterian/Weill Cornell says: • “Cesium131 brachytherapy is nothing less than a new standard of care for treatment of prostate cancer, giving patients an improved quality of life and peace of mind.” • Medical News Today – UK, January 8th, 2006

5. Cesium131 Highlights • Cesium131 isotope offers superior results compared to competitive isotopes due to: • High energy; and • Short (9.7 day) half life • Delivers effective dose 2 - 6 times faster than Pd103 and I125 • IsoRay manufactures Proxcelan™ Cs131implantable seeds, used alone or in combination with devices such as mesh, strands and sutures • Proxcelan™ Cs131seed implant is placed in or around the tumor, or on the surgical margins of a suture site • Minimally invasive • Seeds are placed via needle, sutures, or mesh, and can be directly placed at time of tumor removal

6. Proxcelan™ Cs131 Brachytherapy “seeds” Source: Oak Ridge Associated Universities LDR Brachytherapy for Prostate Cancer Source: Mayo Foundation SAV I Catheter for Breast Cancer Source: Cianna Medical

7. Cesium131 Track Record • Over 7,000 prostate cancer cases treated withProxcelan™ Cs131 • New 5 year prostate cancer treatment data indicate strong efficacy • 98% success (measured by freedom from biochemical failure) • Leading medical institutions are currently collecting data for treatment for the following indications: • Prostate • Lung • Brain • Ocular • Colon • Head and Neck

8. Benefits of Prostate Seed-Implants Source: Frost Sullivan Report 2004

9. Advantages of Cesium131 • High Energy and Short Half Life Make Cesium131the Isotope of Choice for Treatment of Many Disease States • Higher Initial Energy and Faster Delivery Time than Pd103 and I125 • Dose is delivered in advance of absorption of delivery vehicles (mesh and • suture materials) • Cancer cells have less opportunity to repopulate • Greater flexibility due to reduced total radiation to healthy • tissues • Uniform and Symmetrical Radiation Penetration • Improved dose distribution (homogeneity) • Improved placement positioning • Single Application Autoradiograph of an IsoRay seed (4.5 mm)

10. Brachytherapy Implant Comparative Analysis The above information is considered standard dosing information. Such information is governed by the FDA and is required to accompany any product that is distributed to a customer and intended for use.  Acquisition of this information can be obtained from the company that manufactures each listed product.

11. GlioSite ® : Treatment of Brain Cancer • GliaSite® is IsoRay’s newest product offering • The only FDA-approved balloon catheter for brachytherapy of brain cancer • Product launch preparations underway in the US • Reimbursement of the GliaSite® system with I125 is already established for both in-patient and out-patient settings • Negotiating European distribution agreements • Seeking FDA clearance for new liquid form of Cesium131 as alternative to the radioisotope Iotrex™ (I125) with GliaSite® • Cesium131 benefits expected to enhance market adoption rate, size and profit margin

12. Cancer Facts There were an estimated 1,479,3501 new cases of cancer diagnosed in the U.S. in 2010: • Prostate – 217,730 • Lung – 222,520 • Head and Neck – 52,540 • Brain – 22,020 • Eye and Orbit – 2,480 • Breast – 209,000 • Colon – 102,900 • 1- Cancer Statistics, 2010 Jemalet al., Cancer Management: A Multidisciplinary Approach 11th Edition (2008), American Cancer Society 2010

13. IsoRay Market Potential • Total IsoRay Market Potential:$150 Million* • Head and Neck:  2,000 potential cases ($5,950,000.00) (2000 cases x $119 x 25 seeds) • Lung:   4,000 potential cases ($19,040,000.00) (4000 cases x $119 x 40 seeds) • Prostate: 13,000 potential cases ($79,560,000.00) (13,000 cases x $72 asp x 85 seeds) • Ocular Melanoma: ~200 potential cases ( $350,000.00) (200 cases x $119 x 15 seeds) • Brain Cancer (GBM): ~2,000 potential cases ($7,140,000.00) (2000 cases x $119 x 30 seeds) • Breast:  10,000 potential cases ($47,600,000.00) (10,000 cases x $199 x 40 seeds) *assuming the current reimbursement rates (which are subject to annual review and adjustment), remain constant

14. Corporate Strategy • Continue to grow prostate cancer market share • Leverage new positive 5 year data to increase adoption rates • Aggressively market the new GliaSite® system for revenue expansion in the brain cancer treatment market • Capture the lung cancer market • Independent multi-center study now underway • Promote Cesium131 for treatment of colon, head and neck cancer • Develop breastand esophageal cancer market • Evaluate use of Cesium131 in combination with the SAV-I void filling device and others for treatment of breast cancer • Expansion of marketing and distribution in US and the EU

15. Near Term Milestones • Events to broaden prostate and other cancer markets • Independent publication of 5 year data for prostate treatment • Initiation of market use of Proxcelan™Cs131 for “dual therapy” in high risk patients • New MD Anderson clinical comparison of Proxcelan™ Cs131 with other isotopes • Prelaunch marketing and scientific presentations at Miami ASTRO conference • Submission for FDA approval of new liquid Cesium131 formulation • Multiple GliaSite® Events • Review by notified body for CE mark approval • Pending State of Washington approval of radioisotope product manufacturing and delivery to enable initiation of GliaSite® launch • Completion of EU distributorship for GliaSite® • US and EU launch of GliaSite® ! • Expansion to new cancer treatments • Market use of Proxcelan™ Cs131 with SAV-I void filling device for breast cancer • Initiation of esophageal cancer treatment with Proxcelan™ Cs131 in combination with an esophageal stent

16. Financials • Operating loss reductions from decreasing cost of product and sales, and large reduction in cash burn • Continuing trend for increased margins as well as new revenue growth projected with new uses and products in non-prostate cancer applications

17. Summary • Non-prostate applications grew 139% from FY2010 to FY2011 • Positioned to be the leader for brachytherapy cancer treatment with a $150+ million potential market share • Enabled by exclusive patent position for Cs-131 separation process • Broadening to other major cancer markets • Multiple product and market indications for cancer • Current leading prostate cancer treatment, with active expansion to lung and brain cancer treatments • GliaSite® system to enable new brain cancer treatment • FDA approved to take Cesium131 to all cancers • Strong pipeline of near-term milestone events

18. ISORAYWHERE THE FUTURE IS NOWThank You!