See how Cesium Blu by Isoray is being used.

Isoray’s disposable, single use, next-generation device is unique in that it is the first handheld device, offering a new level of maneuverability. Blu Build provides each patient personalized treatment for their specific situation with the unique treatment benefits of Cesium-131 brachytherapy. 

Available for Qualified Clinicians

Loose Seeds

Isoray’s seeds have a gold wire (for visualization) inside a ceramic core (for adhering the Cs-131) encapsulated within a titanium tube. Each seed is rigorously tested before release. Loose seeds are shipped in glass vials contained within a lead pig. Isoray can ship from 1 seed to 1000 seeds per vial at the specific activity requested by the customer.

Mick Cartridge

Spring loaded cartridges holding up to 15 seeds in each cartridge. These magazines, supplied sterile, are used in conjunction with a Mick® Applicator to dispense seeds during the implant.

This device is typically used for prostate treatments and contains an average of 80 seeds per patient.

Stranded Seeds

Needles are placed into a shielded needle tray containing up to 14 needles. An average prostate cases uses approximately 20 needles per patient. The needle trays are sterilized prior to being shipped.


The suture, containing seeds, can be sewn by Isoray into a piece of bio-absorbable mesh which can be sewn or stapled into tissue by the physician for use in the lung, pelvic floor, or even the brain.

Preloaded Stranded Seeds

Strands consist of seeds loaded into bio-absorbable sleeves and may contain bio-absorbable spacers per the physician’s treatment plan.  Essentially the seeds and spacers are “shrink-wrapped” into the sleeve to create a strand.

These strands can be shipped by themselves or loaded into 18 gauge needles in which the ends have been pre-plugged with bone wax.


Seeds can be loaded into bio-absorbable sutures and directly sewn into affected tissue by the physician for treating brain, head and neck, colorectal, and gynecological cancers.


To learn more about Isoray products, contact us below.

Patient Release PDF

Download the radiation exposure rates and patient release information for Cesium-131.

Breakthroughs in brachytherapy by Cesium Pioneers.

Doctors across the US are using Cesium-131 by Isoray in powerful ways with great outcomes.
Check out their work.