IsoRay Announces World`s First Cesium-131 Lung Implants Performed at Cornell Medical Center

RICHLAND, Wash.--(Business Wire)--
IsoRay, Inc. (Amex: ISR) announced today that starting on August 12, 2009, Dr.
Bhupesh Parashar from the Department of Radiation Oncology, and Dr. Nasser
Altorki of the Department of Cardiothoracic Surgery at Weill Cornell Medical
Center performed the world`s first Cesium-131 lung implants.

Four Cesium-131 lung implants were performed at Weill Cornell Medical Center
utilizing a wedge resection technique as a part of the surgical treatment.

Cesium-131 was chosen based on the short half life and higher dose rate. The
short half life allows 99.8% of the treatment dose to be delivered by the time
the sutures and mesh dissolve unlike other isotopes used in this procedure.

Dr. Parashar stated, "Our patients tolerated the procedure well and have had no
evidence of cancer recurrence or any side effects that can be attributed to the
Cesium-131 seed implants as of the last follow-up visits."

Until now clinical experience with Cesium-131 has been focused on prostate
cancer and ocular melanoma. However, Cesium-131 has been cleared by the FDA for
use in the treatment of malignant disease (e.g., prostate, ocular melanoma, head
and neck, lung, brain, breast, etc.) and may be used in surface, interstitial,
and intracavitary applications for tumors with known radiosensitivity.

Dr. Dattatreyudu Nori and Dr. Paul Lee at NYHQ performed an additional Cs-131
implant for a pancoast tumor (a type of lung cancer) after surgical resection of
the tumor.

Dwight Babcock, IsoRay's CEO, stated, "We feel that Cesium-131 has properties
that uniquely position it to be the isotope of choice in many cancers beyond the
prostate. Its short half life lends itself to delivering the dose quickly using
materials meant to dissolve in the body, and Cesium-131 has uniform and
symmetrical radiation penetration for a more homogeneous implant. This allows
physicians to be confident that their intended dose was delivered to the areas
of concern. Because of the positive response from these early patients, IsoRay
is immediately initiating a clinical trial using Cs-131 for Stage I non-small
lung cancers (NSCLC)."

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 or prostate cancer(c) and ocular
melanoma(d), among other cancerous conditions.

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 lung cancers will be successful in the initial and any
future implants, whether a clinical trial for Stage I non-small 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 lung cancers result in favorable patient outcomes, whether resources are
available as needed to conduct a clinical trial for Stage I non-small 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.

IsoRay, Inc.
Dwight Babcock, CEO, 520-240-4840
dbabcock@isoray.com

Copyright Business Wire 2009