About Cesium-131 / History

Scientific research conducted in the 1960’s has now yielded a more powerful and aggressive Brachytherapy treatment for prostate cancer.

Donald C. Lawrence: One of the founding fathers of modern Brachytherapy.

The introduction of Cesium-131 represents the culmination of decades of work and millions of dollars of investment. Top medical centers, hospitals and clinics across the United States are now offering this breakthrough treatment for prostate cancer patients.

Today brachytherapy is one of the most popular methods for treating prostate cancer. The word brachytherapy derives from the Greek prefix brachy, meaning "short" or "close," because the titanium capsules containing the radioisotope are implanted directly into the cancerous prostate gland.

Treatment of cancer using low dose radiation or "seed" brachytherapy was pioneered in the 1960's as an effective alternative to radical surgery. Pioneers in brachytherapy research initially theorized about the use of a titanium capsule using the Cesium-131 radioisotope. Due to scientific and economic limitations at the time, Iodine-125 was selected as an alternative.

Beginning in 1967, Iodine-125 became the first radioisotope manufactured in a titanium capsule, or seed. While its use continues to this day, many patients and doctors in recent years have chosen Palladium-103, a faster-acting, shorter half-life isotope than Iodine-125. In order to obtain the clinical benefits of Palladium's short half-life, patients and clinicians were forced to settle for less energy or tissue penetrating power.

A team of scientists, including Lane A. Bray, now chief chemist of IsoRay Medical, Inc., continued to believe the physical characteristics of Cesium-131 could potentially provide superior clinical benefits for prostate seed brachytherapy patients. Bray eventually developed the patented process for economically separating and purifying Cesium-131. In 1998 IsoRay Medical, Inc. was founded to manufacture and market seeds containing this faster, more aggressive isotope.

Cesium-131 received FDA clearance to market 2003 for treatment of prostate, head and neck, breast, brain, and liver cancers as well as other malignant disease. The first Cesium-131 seed was implanted in a prostate cancer patient at the University of Washington Medical Center on October 2004.