Isoray - Innovative Brachytherapy

Every day patients are treated with our cutting edge technologies.

Read and watch their stories and learn about the innovative doctors around the world helping patients.

Over 19,000+ patients have experienced the power of Cesium-131 for treating cancer.

Learn about the options for you, a friend, or a family member.


Over 10,000 patients treated.


A novel approach for radiation delivery.


An innovative solution for recurrent cancers.

Head & Neck

Delivering personalized radiation to tightly controlled areas.


Customized individual cancer treatment.

Cesium-131 for Prostate Cancer

Not all brachytherapy radioisotopes are the same. Cesium-131 offers you a powerful option for treating prostate and other cancers throughout the body.

Considering multiple treatment options?

Compare the leading treatments for Prostate Cancer and consult your doctor about your options.

   Acceptable side effects comparable to other treatments (1)

   Less impact on urinary function than surgery (1)

   Higher degree of sexual function reported at three year follow up(1)

   45 minutes to 1 hour for complete implant

   Hospitalization rarely required

   First ultrasound guided implant performed in 1985

   Local control rates up to 99% of patients in long term studies (5)

–  Very few GI or rectal side effects have been reported.

–  Higher degree of poor urinary function(1)

–  Higher degree of sexual dysfunction (1)

–  3-4 hours procedure

–  Up to a 4 day hospital stay

–  Early reports of robotic surgery began in 2003 (2)

–  83% local control rates achieved at high volume centers (4

–  Late rectal morbidity likely(3)

–  Urinary bother occurs in 12-40% of patients treated (3)

–  Approximately 78% of patients maintain sexual function (6)

–  Five days per week for up to nine weeks.

–  Hospitalization is rarely required

–  IMRT adaptation acceleration began in 2003

–  89% of patients in local control rates in long term study (3)

10,000+ Men Have Chosen Cesium-131
to Treat Their Prostate Cancer

Compare your options and talk to your doctor.

You have questions — we want to help answer them.

A diagnosis is just the first step toward treating your cancer. We are here to help you make an informed treatment decision with your doctor so you can begin living your life again.

Cs-131 is a favorable isotope for use across a wide range of tumors and its dose distribution properties facilitate easy calculation and use in the clinic.

Voichita Bar Ad, MD

Thomas Jefferson University Hospital

Is brachytherapy only for prostate cancer treatment?

No. While brachytherapy has been used extensively over time to treat prostate cancer, its application goes beyond prostate to other treatment areas. We are seeing particularly exciting applications in head/neck, brain, as well as other treatment areas.

What is brachytherapy?

With brachytherapy (or seed therapy), cancer-fighting medical radioisotopes are implanted in and/or around the affected tissue, as close to the cancer as possible. The isotopes are encased in capsules the size of a grain of rice and release a radiation dose, tailored to each patient, over a period of days. This allows doctors to effectively treat the infected area without damaging nearby tissue, and thereby reducing negative side effects. Learn more about brachytherapy here.

How effective is brachytherapy relative to other treatment types?

Brachytherapy has been found to be just as effective as other forms of treatment but has the benefit of shorter treatment times as well as having less side effects. Learn more about brachytherapy here.

What are the advantages of Cesium-131 by Isoray over other isotopes?

Cesium-131 by Isoray has a higher average energy as well as a shorter half life than other commonly-used radioisotopes (I-125, Pd-103). Benefits of these unique attributes are a reduction in some common prostate side effects (such as urinary or sexual performance side effects), greater coverage of the infected organ, and a reduction of the total radiation treatment time. Learn more about the benefits of Cesium-131 by Isoray here.

Who can I speak with regarding my treatment?

We're proud to be connected to many of the finest brachytherapy practitioners in the US. You can learn more about their work as well as contact them directly via our Cesium Pioneers page.


1. John B. Malcolm et al. Quality of Life After Open or Robotic Prostatectomy, Cryoblation or Brachytherapy for Localized Prostate Cancer. Journal of Urology, Vol 183, 1822-1829, May 2010.

2. Jim C. Hu et al. Utilization and Outcomes of Minimally Invasive Radical ProstatectomyJournal of Clinical Oncology, Vol 24, Number 14, May 10 2008.

3. Michael J. Zelefsky et al. Comparison of Tumor Control and Toxicity Outcomes of High Dose Intensity Modulated Radiotherapy and Brachytherapy for Patients with Favorable Risk Prostate Cancer. Urology, Vol 77, Issue 4, Pgs 986-999, April 2011.

4. Robotic Prostatectomy FAQ’s. City of Hope Web Site, 2012.

5. Gregory S. Merrick et al. Brachytherapy in Men Aged ≤54 Years with Clinically Localized Prostate Cancer. British Journal of Urology, Vol 98, Pgs 324-328, 2006.

6. Nathan C. Sheets et al. Intensity-Modulated Radiation Therapy, Proton Therapy, or Conformal Radiation Therapy and Morbidity and Disease Control in Localized Prostate Cancer. JAMA, Vol 307, Number 15, April 18, 2012

View the Prostate Cancer Patient Guide from