Product Catalog
HOME / BRACHYTHERAPY SOLUTIONS / PRODUCTS / SEEDS / CESIUM-131
Cesium-131
Brachytherapy Seed
A Versatile Choice for LDR Brachytherapy.
With high energy and a short half-life, Cesium-131 seeds are designed to treat a variety of cancers including prostate cancer, head & neck, and lung.
* Seed not to scale – Cesium-131 is 4.5mm long x 0.84mm high
Cesium-131 is indicated for the treatment of localized and unresectable tumors with low to moderate radiosensitivity.
Tumors may be recurrent or residual following external beam radiation or excision of primary tumor.
Backed by more than 10 years of clinical use
- High Energy 30.4 KeV
- Allows for a Uniform Dose distribution
- Short Half-Life 9.7 day half-life
- Results in a shorter duration of radiation which may contribute to a rapid resolution of patient side effects
Cesium-131 can be supplied in a range of brachytherapy devices and delivery methods
Cesium-131 is available in a range of brachytherapy devices and delivery configurations designed to support different clinical needs and procedural workflows.
As the exclusive distributor, we offer a comprehensive portfolio of strands, preloaded needles, and carriers, supported by personalized customer service.
Our goal is to provide clinicians with the flexibility, procedural efficiency, and support needed to deliver targeted brachytherapy and quality patient care.



Cesium-131 seeds – titanium cased seed containing a gold wire for easy visualization.
Cesium-131 Strands contain seeds and bio-absorbable spacers placed end to end within a bio-absorbable sleeve. The seeds and spacers are sealed within the sleeve, allowing the strand to be implanted as a unit.
Designed to reduce the potential for individual seed migration and also accommodates extracapsular extension dose coverage when planned appropriately.
Design
- Designed to reduce seed migration
- Linking, bio-absorbable sleeve
- Bioabsorbable spacer
- Bioabsorbable sleeve dissolves after implant
Cesium-131 seeds are loaded into Mick cartridges and can be used in conjunction with a Mick Applicator, ideal when individual seed placement is desired.
Design
- Organized magazine of seeds for fast placement.
- Works with multiple delivery systems.
Cesium-131 Stranded or Loose Seeds can be preloaded into 18 gauge needles and placed into a shielded tray, which also doubles as a needle stand.
Design
- Bone wax filled tipped to secure strand in place prior to implant
- Square hub and round hub needle options
- 18 gauge needles
- Sterilized needle tray doubles as a stand for intraoperative use
Cesium-131 Strand Tray delivery system empowers clinicians by organizing and measuring Cesium-131 Strands while in the OR.
The custom designed, shielded, stainless steel tray organizes strands for clinicians who pre-plan cases or those that prefer to do real-time dosimetry and modify strands in the OR. Stand Tray is a modern tool for today’s brachytherapist.
Design
- Shielded stainless steel delivery tray that protects strand structure
- Slotted insert for ease of strand removal from tray
- Strand length measurement assist ruler built in
- Strand Tray is used to ship Cesium-131 Strands individually ready for implantation.
Cesium-131
Interested in learning more?
Theragenics is an authorized distributor of Cesium-131 LDR brachytherapy seeds.
Cesium-131 and associated product offerings are manufactured by GT Medical Technologies, Inc, Tempe, AZ
Cesium-131 source and accessories should be used by physicians who are qualified by training and experience in the safe use and handling of radionuclide brachytherapy sources and whose experience and training has been approved by the appropriate government authorities authorized to license the use of radioactive materials.
Information intended for the USA. Indications may vary in different countries; please either consult the appropriate IFU or your local distributor.
Related Products

TheraSeed®
Palladium-103 Seeds
Brachytherapy Seeds

Cesium-131 Seeds
Brachytherapy Seeds
About Us
We design and deliver innovative solutions that consistently improve patient outcomes.
Careers
Ready to join a dynamic team committed to advancing medical device innovation?