International Isotopes Inc. Launches Commercial Sale of Iodine-131

IDAHO FALLS, Idaho, March 22 /PRNewswire-FirstCall/ -- International Isotopes Inc. (OTC Pink Sheets: INIS), a manufacturer of nuclear medicine calibration and reference standards and radioisotopes for medical devices and clinical research, has announced the launch of their newest product offering -- Iodine-131. The announcement of this product launch coincides with the start of product sales this week.

Iodine-131 is currently being used for the treatment of and diagnosis of various diseases related to the thyroid such as Hyperthyroidism and thyroid cancer. The National Cancer Institute estimates there are about 22,000 cases of thyroid cancer diagnosed each year in the U.S. Thyroid cancer is commonly treated by a combination of surgery followed by administration of I-131. Hyperthyroidism is caused by the excess production of thyroid hormones and effects more than a million adult females each year in the U.S. I-131 administration is a well-proven method of treating this condition. I-131 is also being used in a host of investigational and clinical trials for cancers of the breast, lung, prostate, and ovaries.

International Isotopes Inc. completed the supply agreement for this isotope in mid 2003 and since that time has been installing hot cells, amending licensing, training production staff, and putting a customer order and distributor network in place. All of this work has culminated in the launch of commercial sales this week.

Company Chief Executive Officer Steve T. Laflin stated, “International Isotopes is pleased to add Iodine-131 to the growing list of products we have been able to put in place over the past year.”

In August 2003, the Company announced the launch of Lutetium-177 radiochemical sales for clinical research and added several other products to its line of nuclear medicine reference and calibration standards. Additional information on I-131 or any of the other Company products can be found on the Company’s website http://www.intisoid.com/ or obtained directly through the Company customer service representative, Lucinda Sherman, voice (208) 524-5300, fax (208) 524-1411, e-mail lsherman@intisoid.com .

About International Isotopes Inc.

International Isotopes Inc. manufactures a full range of nuclear medicine calibration and reference standards and provides a selection of radioisotopes and radiochemicals for medical devices, calibration, clinical research, life sciences, and industrial applications. The Company also provides a host of analytical, measurement, and processing services on a contract basis to clients.

International Isotopes Inc. Safe Harbor Statement

Statements in the press release may constitute forward-looking statements and are subject to numerous risks and uncertainties, including the ability to meet time schedules, the need to raise additional capital, the development of competitive products by others and other risks detailed from time to time in the Company’s filings with the Securities and Exchange Commission. The Company disclaims any obligation to update statements in this press release.

For More Information, Contact: Steve Laflin, President and CEO (208) 524-5300

International Isotopes Inc.

CONTACT: Steve Laflin, President and CEO of International Isotopes Inc.,+1-208-524-5300