Radiomicrosphere Dosimetry: Principles and Current State of the Art.

Area of Science:

• Nuclear Medicine
• Oncology
• Radiopharmaceutical Therapy

Background:

• Radiomicrosphere Therapy (RMT) is a liver-directed treatment involving intrahepatic arterial administration of radiolabeled microspheres.
• Current clinical RMT options include Y-90 resin, Y-90 glass, and Ho-166 PLLA microspheres.
• Standardization of RMT terminology is necessary for clarity and consistency.

Purpose of the Study:

• To review and standardize the terminology for Radiomicrosphere Therapy (RMT).
• To focus on Yttrium-90 (Y-90) resin and glass RMT, detailing their history, dosimetry, clinical applications, and associated controversies.
• To discuss the importance of radioisotope and microsphere composition in dosimetric considerations.

Main Methods:

• Literature review focusing on Y-90 resin and glass RMT.
• Analysis of existing clinical RMT options and emerging preclinical studies (e.g., Re-188 PLLA RMT).
• Examination of dosimetric principles related to radioisotope and microsphere characteristics.

Main Results:

• Proposed a standardized nomenclature: radioisotope, chemical formulation, and RMT.
• Identified Y-90 resin RMT, Y-90 glass RMT, and Ho-166 PLLA RMT as current options.
• Highlighted ongoing preclinical research with Re-188 PLLA RMT and regulatory considerations for Ho-166 PLLA RMT in the US.

Conclusions:

• Standardized terminology for Radiomicrosphere Therapy is crucial for clear communication and research.
• Y-90 resin and glass RMT represent established therapeutic modalities with distinct properties.
• Dosimetry in RMT is critically dependent on both the radioisotope and the microsphere's chemical composition.