History of Proxcelan™ brachytherapy seeds
History of Cesium-131 Seeds
The introduction of Proxcelan™ seeds (Cesium-131) represents the culmination of decades of work and millions of dollars of investment. Pioneers in brachytherapy research initially theorized about the use of Cesium-131 in a titanium capsule, however scientific and economic limitations at the time prevented its development. As a result, Iodine-125 emerged 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 Donald C. Lawrence, one of the founding fathers of seed brachytherapy, continued to believe the physical characteristics of Cesium-131 could potentially provide superior clinical benefits for prostate seed brachytherapy patients. This team of scientists eventually developed the patented economical process for separating and purifying Cesium-131. In 1998, IsoRay Medical, Inc. was founded to manufacture and market seeds containing Cesium-131.
In 2003, Proxcelan™ seeds received FDA clearance for use in the United States with the indication “treatment of malignant disease of the head and neck, brain, breast, prostate and other organs”. The first Proxcelan seed implant was performed at the University of Washington Medical Center in Seattle in October 2004. To date there have been more than 1,200 Proxcelan seed implants performed and Proxcelan seeds are offered at over 50 clinics across the United States.
