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TheraSphere Y-90 Glass Microspheres being administered to treat HCC.

TheraSphere™ Y-90 Glass Microspheres

Dosage and administration

Confidently dose during recommended treatment days while maintaining a good patient safety profile

Contemporary dosing recommendations below from an international multi-disciplinary working group were driven by TheraSphere landmark studies and advancing Y-90 techniques to improve outcomes. Recommendations include: 

  • Five clinical scenarios (curative and palliative intent) to facilitate standardized personalized treatment to improve outcomes
  • Targeted absorbed dose in selective treatment of ≥ 400 Gy for complete pathologic necrosis radiation (single compartment)
  • Tumor absorbed dose of ≥ 205 Gy (> 250 Gy where possible) and normal absorbed dose in the perfused liver of ≤ 120 Gy in patients with ≥ 30% hepatic reserve (multi-compartment)

Mechanism of action = radiation

TheraSphere is uniquely engineered to have unmatched radiation per microsphere (RPM), maximizing lethal hits to tumor DNA and driving tumor cell death.

TheraSphere Y-90 Glass Microsphere.

TheraSphere Y-90 Glass Microsphere

Radiation is embedded within the glass matrix, providing greater RPM

Y-90 resin microsphere.

Y-90 Resin Microsphere

Radiation is only coated onto the surface area of the resin sphere,¹ limiting RPM

TheraSphere Y-90 glass microspheres maintain a higher RPM over time

With unmatched RPM, TheraSphere maximizes repetitive and cumulative radiation exposure to tumor cells to achieve complete pathological necrosis (CPN) at ablative doses.

TheraSphere glass maintains a higher RPM over time.

Personalized dosing. Simplified.

Simplicit90Y™ personalized dosimetry software, developed exclusively for TheraSphere Y-90 Glass Microspheres, allows you to enhance the consistency and efficiency of your dosing calculations. The software enables visualization of prospective dose distribution and assessment of the absorbed dose delivered to provide optimal ability to calculate confidently.

Double desktop monitor showing Simplicit90Y personalized dosimetry software for TheraSphere Y-90 Glass Microspheres.

TheraSphere is the only radiation therapy with Level 1 randomized data to demonstrate efficacy in large liver tumors (mean tumor size of 10.5 cm)⁵ while also validating reproducible dosimetry planning with Simplicit90Y™ Personalized Dosimetry Software.⁶

Doses comprised of fewer spheres and higher RPM spare more normal tissue

Pre-clinical study using TheraSphere Y-90 Glass Microspheres confirmed treatments at or before 8 days post calibration decreases normal liver toxicity.7

4 days post calibration: more healthy tissue spared with higher RPM and fewer spheres.  12 days post calibration: more healthy tissue exposed with lower RPM and more spheres.


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  1. Grosser OS, Ruf J, Pethe A, Kupitz D, Wissel H, Benckert C, Pech M, Ricke J, Amthauer H. Urinary Excretion of Yttrium-90 after Radioembolization with Yttrium-90-Labeled Resin-based Microspheres. Health Phys. 2018 Jan;114(1):58-63. doi: 10.1097/HP.0000000000000734. PMID: 29049048.
  2. Radiation per microsphere (RPM) is a number that refers to the specific activity (SA) of a microsphere (Bq/Sphere). The RPM for TheraSphere is calculated based on targeted values and process means. Actual RPM can vary between microspheres. All numbers as of Noon Eastern Time. Ref Technical Report 97124387.
  3. Salem, R., Padia, S.A., Lam, M. et al. Clinical, dosimetric, and reporting considerations for Y-90 glass microspheres in hepatocellular carcinoma: updated 2022 recommendations from an international multidisciplinary working group. Eur J Nucl Med Mol Imaging 50, 328 -343 (2023).
  4. SIR-Spheres® Y-90 Resin Microspheres IFU media/169247/ssl-us-14-sir-spheres-microspheres-ifu-us.pdf. Data on file.
  5. TheraSphere™ Y-90 Glass Microspheres DOSISPHERE-01 Study. Data on file.
  6. Lam, M., Garin, E., Maccauro, M. et al. A global evaluation of advanced dosimetry in transarterial radioembolization of hepatocellular carcinoma with Yttrium-90: the TARGET study. Eur J Nucl Med Mol Imaging (2022).
  7. Pasciak, A. S., Abiola, G., Liddell, R. P., Crookston, N., Besharati, S., Donahue, D., Thompson, R. E., Frey, E., Anders, R. A., Dreher, M. R., & Weiss, C. R. (2019). The number of microspheres in Y90 radioembolization directly affects normal tissue radiation exposure. European Journal of Nuclear Medicine and Molecular Imaging, 47(4), 816–827.