Cesium-131 radioactive isotope seed from IsoRay Medical™ spotlighted at 48th annual AAPM meeting; breakthrough offers aggressive new option for treatment of prostate cancer

FDA-cleared medical isotope for prostate and other malignant cancers

RICHLAND, Washington--A powerful new medical isotope-- Cesium 131™-- is providing a fast and effective treatment option for prostate cancer patients nationwide. Offering significant advantages over other medical isotopes now in use, Cesium-131 represents the first major leap in seed brachytherapy in 20 years.

This major advancement in seed brachytherapy will be spotlighted at booth #141 during the 48th Annual Meeting of The American Association of Physicists in Medicine (AAPM), July 30-August 3, 2006 in Orlando, FL, at the Orange County Convention Center.  AAPM (www.aapm.org) is a scientific, educational, and professional organization of more than 6,000 medical physicists.

“Brachytherapy has proven to be effective, but the introduction of Cesium-131 takes this treatment option to a new level. Attendees at AAPM will be introduced to a breakthrough option for fast and effective treatment of prostate cancer,” said Chairman and CEO Roger Girard.

Seed brachytherapy--where seeds are implanted in and around a cancerous tumor-- is a proven and common treatment for prostate cancer, with 50,000 to 60,000 procedures conducted each year. Clinical data shows that patient outcomes for seed brachytherapy are superior to those for radical prostatectomy, external beam radiation, IMRT, cryotherapy and experimental procedures at far less cost and with a much higher quality of life.  

Now available in over 50 locations across the United States, Cesium-131 delivers its therapeutic radiation faster than other isotope seeds-- Palladium-103 and Iodine-125--and at a reduced risk to patients when compared to surgery and other treatment options.

Cesium-131 is a proprietary product of IsoRay, Inc. (“IsoRay”) (OTCBB Symbol: ISRY), an innovative medical technology company based in Richland, WA. Cesium-131 received Food and Drug Administration 510(k) clearance in March 2003.

Due to its unique characteristics, Cesium-131 patients receive a higher initial dosage of radiation that kills cancer cells more quickly. Its short half-life means that radiation leaves the body sooner than other isotope options.

“Initial research indicates that patients who select Cesium-131 typically experience a shorter duration of normal side effects when compared with other isotope seeds,” said Dr. Steven M. Kurtzman, medical advisor for IsoRay Medical™ and director of Brachytherapy for Western Radiation Oncology in San Mateo, California. “This allows patients to return to normal activities sooner while the seeds continue to attack cancer cells.”

Cesium-131 has significant advantages over Palladium-103 and Iodine-125.  A fast-acting isotope, Cesium-131 delivers 90% of its dose in just 33 days. With reduced chances of normal tissue exposure, Cesium-131 has a 9.7-day half-life (compared to 60 days for Iodine-125 and 17 days for Palladium-103) delivering less total radiation to the patient while achieving a more homogeneous implant.

Cesium-131 also provides superior tumor penetration.  The energy level of the isotope is 29 KeV, providing more than 30% greater penetration of the cancerous tissue than Palladium-103. The Cesium-131 seeds can also be manufactured “to order” based on patient needs.

Girard, Dr. Kurtzman and other IsoRay Medical™ executives will be on hand at the IsoRay Medical™ booth during this year’s meeting, which organizers expect to be the most highly attended AAPM meeting to date.

A seed brachytherapy procedure involves the use of special needles to implant the seeds, which are smaller than a grain of rice, using ultrasound guidance.  The implant procedure is fast and convenient and the patient typically returns to normal daily activities within two to three days. 

Since it was introduced in October 2004, over 400 patients have been treated with the Cesium-131 isotope at leading cancer treatment hospitals and clinics across the United States. The centers for Medicare and Medicaid Services have established a specific reimbursement code for Cesium-131, and most insurance companies also cover the cost of the brachytherapy procedure, a common and widely accepted treatment option.

Although IsoRay Medical’s Cesium-131 seeds have been used exclusively for treatment of prostate cancer to date, Cesium-131 has FDA clearance for the treatment of any malignant disease, including cancers of the head and neck, brain, breast, prostate, and other organs. 

Initial development of the Cesium-131 seed began more than 40 years ago, but scientific and economic considerations prevented its complete development. Lane A. Bray, chief chemist of IsoRay Medical™, eventually developed the patented process for economically separating and purifying Cesium-131.

For more information on the Cesium-131 cancer treatment breakthrough, visit www.cesium131.com or www.isoray.com.

About IsoRay

IsoRay, Inc., 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, lower probability of cancer cell survival and reduction of the longevity of common brachytherapy side effects.  IsoRay is based in Richland, Washington.  More information is available about IsoRay at www.isoray.com.

Safe Harbor Statement

Statements in this news release about IsoRay’s future expectations, including: the advantages of our Cesium131seed, future production capabilities, development of protocols for the use of our Cesium131 seed to treat cancers other than prostate cancer, the level of market share our seed may attain, and all other statements in this release, other than historical facts, are forward-looking statements.  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, and our ability to enforce our intellectual property rights, and other risks detailed from time to time in IsoRay's reports filed with the SEC.

Media Contacts:

NOTE: For on-site media at AAPM, IsoRay Medical™ press kits will be available in media registration packets and at the IsoRay Medical™ booth (#141). For additional inquiries, contact:

Roger Girard, Chairman and CEO
IsoRay, Inc. 206.849.6507 (cell)
rgirard@isoray.com

Barry Bartlett, The Bartlett Group Public Relations
206.285.0673; 206.335.4694 (cell)
barry@bartlettgrouppr.com

IsoRay Medical™, Inc.                                                             
350 Hills Street, Suite 106
Richland, WA 99352

1.877.4.ISORAY
509.375.1202 TEL                                                     
509.375.3473 FAX