Evaluating ²¹²Pb Human Dosimetry Using ²⁰³Pb SPECT Imaging of an Integrin-Targeting Peptide

²¹²Pb Human Dosimetry Estimates Derived from ²⁰³Pb SPECT Imaging of an Integrin-Targeting Peptide and the Impact of ²¹²Bi Dissociation on Kidney Dose

Radioligand therapy (RLT) with alpha-emitting isotopes such as ²¹²Pb is gaining attention for its ability to deliver potent, localized radiation to tumors while minimizing off-target effects. Accurate dosimetry estimates are critical to optimize efficacy and manage safety risks associated with radionuclide decay and daughter redistribution.
This study used ²⁰³Pb SPECT imaging to predict human dosimetry of a ²¹²Pb-labeled integrin-targeting peptide, evaluating the effect of ²¹²Bi dissociation on kidney dose. SPECT imaging revealed notable early uptake in the kidneys and bladder, with urinary clearance over time and predominant renal retention at 24 hours post-injection.

Dosimetry modeling showed kidneys received the highest absorbed dose (≈89–93 mSv/MBq), followed by osteogenic cells or salivary glands depending on correction parameters. All other tissue doses were comparatively low (0.26–1.57 mSv/MBq). These results underscore the importance of isotope-specific imaging in estimating human radiation burden and refining safety profiles for alpha-emitting radiopharmaceuticals.

This work demonstrates how preclinical and translational imaging data can be leveraged to inform clinical dose planning, support regulatory submissions, and guide RLT development strategies across multiple therapeutic targets.

Why Download the Poster:

• Quantify alpha-emitter safety: See how ²⁰³Pb imaging predicts ²¹²Pb biodistribution and kidney dose, supporting smarter isotope selection.
• Bridge imaging and therapy: Understand how matched-isotope imaging accelerates clinical translation for ²¹²Pb-based radioligands.
• Collaborative innovation: Explore results from a joint Perceptive Discovery and Barts Cancer Institute effort advancing precision dosimetry for RLT.