Next-Generation Laser Welding Produces Cancer Therapy Products

Originally Published MDDI March 2003R&D DIGESTNext-Generation Laser Welding Produces Cancer Therapy Products

March 1, 2003

2 Min Read
Next-Generation Laser Welding Produces Cancer Therapy Products

Originally Published MDDI March 2003


Brachytherapy seed components fit within the titanium capsule. Center laser rotary welding methods are used to place ceramic beads at each end to reduce seed rotation and “cool” spots.

Although prostate cancer is the second-leading cause of cancer death in men, in most cases, the disease is confined to the gland itself. One common treatment, brachytherapy, involves implanting small radioactive pellets or "seeds" into the prostate to deliver radiation directly to the malignancy. 

The technique has grown in popularity because confining and targeting the therapy directly to the cancer site can significantly reduce side effects to the rest of the body. The method can also lead to more-rapid patient recovery, lower costs, and reduced incidence of complications. Now, an improved technique for producing brachytherapy seeds may offer several key advantages.

The improved type of brachytherapy implant, called BrachySeed, has been developed by Draximage, a subsidiary of Draxis Health Inc. (Kirkland, QC, Canada). GSI Lumonics, the manufacturer of the pulsed Nd:YAG lasers used in seed production, has also been involved in the project.

Draximage president Richard J. Flanagan explains that BrachySeed is a next-generation brachytherapy implant that exhibits several important improvements over current implants. Among these are "near-perfect spherical dosimetry and double encapsulation for additional patient safety."

The first BrachySeed implant used iodine-125, a short-lived isotope with a half-life of 60 days, meaning that after 200 days, 90% of the radioactivity within the implanted seeds would have decayed or become nonactive. 

Last November the company received final approval from the U.S. Nuclear Regulatory Commission (NRC) for a palladium version of the technology. Palladium-103 seeds decay at three times the rate of iodine-125 seeds, allowing a more intense initial dose of radiation for use primarily in treatment of more-aggressive tumors. 

The patented BrachySeed products are manufactured using full robotic assembly. Roughly the size of a grain of rice, each seed component fits precisely within a titanium capsule to minimize movement. Ceramic-bead placement at the extreme ends of the capsule through the use of a center laser rotary weld results in isotropic dosimetry. This reduces the impact of seed rotation and its resultant "cool" spots, according to GSI. The firm adds that the laser's fast action was found to minimize distortion during fabrication of the seed. Using the laser, a seed can be welded in a few seconds.

Copyright ©2003 Medical Device & Diagnostic Industry

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