Theragenics Announces Receipt of World's First NIST Traceable Standard for TheraSeed Palladium 103.

ATLANTA--(BUSINESS WIRE)--Feb. 19, 1999--Theragenics Corporation (NYSE symbol TGX), the Atlanta-based cancer treatment producer, today announced it has received the world's first NIST  Traceable Standard for TheraSeed(R)-Palladium 103 (Pd103) from the National Institute of Standards and Technology (NIST). This federal technology agency, NIST, works with companies to develop and apply technology, measurements and standards.

Theragenics' ability to swiftly obtain this standard is a result of collaboration between the Company, NIST and the American Association of Physicists in Medicine (AAPM). Prior to securing its NIST standard, Theragenics maintained its own standard for TheraSeed(R). Dosimetry studies conducted during the 1980's provided information used by the medical physics community for the thousands of implants conducted since the Company's Pd103 brachytherapy source, TheraSeed(R), was first introduced during 1987.

The significance of obtaining the NIST Traceable Standard for Pd103 is that it is unique to Theragenics' TheraSeed(R) brachytherapy source. No other isotope or seed manufacturer can use Theragenics' exclusive standard.

Theragenics' scientists and engineers worked closely with NIST and the AAPM to address the technical issues and unique properties of TheraSeed(R). The existence of this standard will result in an independent measurement of Air Kerma Strength, a vital component used in calculations made by physicists to facilitate the use of TheraSeed(R) in cancer treatment. The Company will continue working with these organizations to ensure proper implementation of its standard by the medical physics community.

Commenting on this milestone, Christine Jacobs, Theragenics' chairman, president and CEO said, "Theragenics has once again proven its leadership in the brachytherapy industry by becoming the first company to obtain this significant Pd103 standard. I believe it will be crucial for every company producing brachytherapy sources to secure and preserve its own NIST Traceable Standard to effectively compete in the marketplace. Dedication to patients and the quality of our devices is and will remain our top priority."

Burt Coursey, chief of NIST's Ionizing Radiation Division, commented, "The world's first standard for Pd103 is the result of a 15-month concerted effort by NIST and Theragenics. This standard demonstrates commitment from government and industry to maintain the highest quality standards possible for health care in the United States." The Council on Ionizing Radiation Measurement and Standards (CIRMS), an independent organization representing users of ionizing radiation and radioactive sources, has identified the need for standards for Pd103 as one of the nation's major health care needs today.

Except for historical information contained herein, the matters discussed in this press release are forward looking statements, the accuracy of which is necessarily subject to risks and uncertainties. Actual results may be affected by, among other things, risks and uncertainties related to new process development cycles, potential costs and delays in capacity expansion, research and development activities, effectiveness and execution of marketing and sales programs, continued acceptance of the product by the market, introduction and/or availability of competitive products by others, third party reimbursement, physician training, and other factors set forth from time to time in the Company's Securities and Exchange Commission filings.

Theragenics Corporation, based in Norcross, GA, is the manufacturer of TheraSeed(R), a rice-sized device used in the treatment of localized prostate cancer with a one-time, minimally invasive procedure. For additional information on the Company, call Theragenics' Investor Relations Department at [phone]. The Company's common stock is traded on the New York Stock Exchange under the symbol TGX.