Modern brachytherapy starts here.

With a higher energy, greater coverage, short Half-Life and a quick recovery time for most patients, there’s no surprise!

Cesium-131 is a game changer for Brachytherapy and Cancer treatment – it treats cancer at the source, with rapid resolution of side-effects for the patient and is very-cost effective for you and your colleagues.

clinician at microscope cesium 131 icon

Your Isotope Choice Makes a Difference

Not all brachytherapy radioisotopes are the same. Compared to alternative brachytherapy seeds, Cesium-131 offers the highest energy and shortest half-life.

Isotope Introduced Half life Kev Delivery rate Detectable in the body
Iodine-125 1965 60 Day 20.8 204 Days for 90% Dose 600 Days
Palladium-103 1987 17 Day 28.5 58 Days for 90% Dose 170 Days
Cesium-131 2004 9.7 Day 30.4 33 Days for 90% Dose 97 Days
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Higher Energy

Perspective Therapeutics' proprietary isotope, Cesium-131, has a higher energy allowing for a more uniform dose distribution with less overdosing than other permanent isotopes.

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Shorter Half-Life

Perspective Therapeutics' proprietary isotope, Cesium-131, has a shorter half-life than other commonly used isotopes for the treatment of cancer throughout the body, resulting in a shorter duration of radiation which contributes to a rapid resolution of patient side effects. (2)

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Improved Coverage of the Prostate

Cesium-131 proprietary permanent prostate cancer brachytherapy seeds allow for better dose homogeneity and the sparing of the urethra and rectum while providing comparable prostate coverage compared to other seeds with comparable or fewer seeds and needles. (3, 4, 5, 6)

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Rapid Resolution of Side effects

Our proprietary isotope, Cesium-131, has a shorter half-life than other commonly used isotopes for the treatment of cancer throughout the body, resulting in a shorter duration of radiation which contributes to a rapid resolution of patient side effects. (7, 8, 9, 10)

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Higher Biologically Effective Dose

Cesium-131 also delivers a higher "biological effective dose" or BED compared to I-125 or Pd-103 across a wide range of tumor types. (11)

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PSA Control

Investigators tracking PA in both single arm and randomized prostate cancer treatment trials have concluded that Cesium-131 PA response rates have similar early tumor control to 1-125, which was previously considered the gold standard in permanent seed brachytherapy. (8, 12, 13)

A Modern Toolset for All Techniques of LDR Brachytherapy

We understand that every clinician has different requirements and methods of working, that’s why we offer a range of solutions that are designed to make your life easier and more cost-efficient.

From loose seeds and preloaded needles to cartridges and braided sutures we have not only what you need but what your patients require


1. Prestidge B.R., Bice W.S., Jurkovic I., et al. Cesium-131 Permanent Prostate Brachytherapy: An Initial Report. Int. J. Radiation Oncology Biol. Phys. 2005: 63 (1) 5336-5337.
2. Neill B, et al. The Nature and Extent of Urinary Morbidity in Relation to Prostate Brachytherapy Urethral Dosimetry. Brachytherapy 2007:6(3)173-9.
3. Musmacher JS, et al. Dosimetric Comparison of Cesium-131 and Palladium-103 for Permanent Prostate Brachytherapy. Int. J. Radiation Oncology Biol. Phys. 2007:69(3)5730-1.
4. Yaparpalvi R, et al. Is Cs-131 or 1-125 or Pd-103 the "Ideal" Isotope for Prostate Boost Brachytherapy? A Dosimetric View Point. Int. J. Radiation Oncology Biol. Phvs. 2007:69 (3)5677-8.
5. Sutlief S, et al. Cs-131 Prostate Brachytherapy and Treatment Plan Parameters. Medical Physics 2007:34(6)2431.
6. Yang R, et al. Dosimetric Comparison of Permanent Prostate Brachytherapy Plans Utilizing Cs-131, 1-125 and Pd-103 Seeds. Medical Physics 2008:35(6)2734.
7. Prestidge B, et. al. Clinical Outcomes of a Phase-II, Multi-institutional Cesium-131 Permanent Prostate Brachytherapy Trial. Brachytherapy. 2007: 6 (2)78.
8. Moran B, et al. Cesium-131 Prostate Brachytherapy: An Early Experience. Brachytherapy 2007:6(2)80.
9. Jones A, et al. IPSS Trends for Cs-131 Permanent Prostate Brachytherapy. Brachytherapy 2008:7(2)194.
10. DeFoe SC, et al. Is There Decreased Duration of Acute Urinary and Bowel Symptoms after Prostate Brachytherapy with Cesium 131 Radioisotope? Int. J. Radiation Oncology Biol. Phys. 2008:72(57)5317.
11. Armpilia CI, Dale RG, Coles IP et al. The Determination of Radiobiologically Optimized Half-lives for Radionuclides Used in Permanent Brachytherapy Implants. Int. J. Radiation Oncology Biol. Phys. 2003; 55 (2): 378-385.
12. Bice W, et. al. Recommendations for permanent prostate brachytherapy with 131Cs: a consensus report from the Cesium Advisory Group. Brachytherapy 2008:7(4)290-296.
13. Platta CS, et al. Early Outcomes of Prostate Seed Implants with 131Cs: Toxicity and Initial PSA Dynamics from a Single Institution. Int. J. Radiation Oncology Biol. Phys. 2008:72(S1)5323-4.
14. Tomaszewski JJ, et al. Cesium 131 versus iodine 125 implants for prostate cancer: evaluation of early PSA response. The Canadian Journal of Urology. 2010;17(5): 5360-5364.
15. R.M. Benoit, R.P. Smith, S. Beriwal. Five Year Prostate-specific Antigen Outcomes after Caesium Prostate Brachytherapy. Clinical Oncology. 26 (2014) 776 780.
16. Brian J. Moran, MD, Michelle H. Braccioforte, MPH. Prostate Cancer Foundation of Chicago, Westmont, IL. PSA Outcomes in a Single Institution, Prospective Randomized 13]Cs/125l Permanent Prostate Brachvtherapv Trial Abstracts / Brachvtheraov. 13 (2014) S15eS126.
17. Amit B. Shah, MD, Arnav A. Shah, Gregory A. Fortier, MD. Radiation Oncology, York Cancer Center, Wellspan Health, York, PA. A Comparison of AUA Symptom Scores following Permanent Low-Dose-Rate Prostate Brachytherapy with lodine-125 and Cesium-131, Abstracts / Brachytherapy 12 (2013) SileS77.
18. Herstein A, Wallner K, Merrick G, Mitsuyama H, Armstrong J, True L, Cavanagh W, Butler W. 1-125 versus Pd-103 for low-risk prostate cancer: long- term morbidity outcomes from a prospective randomized multicenter controlled trial. Cancer J. 2005 Sep-Oct;11(5):385-9.