Biodistribution and Radiation Dosimetry of [ 68 Ga]Ga-RAYZ-8009, a Glypican 3–Targeting Compound for Imaging of Hepatocellular Carcinoma

Glypican 3 is highly expressed in hepatocellular carcinoma (HCC), rendering it a promising target for disease imaging. [⁶⁸Ga]Ga-RAYZ-8009 is a recently introduced PET tracer selective for glypican 3. To further assess the safety and suitability of this radiopharmaceutical in a clinical setting, whole-body distribution and radiation dosimetry were evaluated. Methods: Six patients with histologically confirmed HCC or clinical or imaging-based suspicion of HCC were intravenously injected with 103-167 MBq of [⁶⁸Ga]Ga-RAYZ-8009 (mean ± SD, 150 ± 22 MBq). Whole-body PET/CT scans were acquired at 10 min, 1 h, 2 h, 4 h, and 7 h after tracer injection. Time-activity curves per organ were determined, and mean organ-absorbed doses and effective doses were calculated using IDAC-Dose 2.1. Results: Injection of a standard activity of 150 MBq of [⁶⁸Ga]Ga-RAYZ-8009 resulted in a median effective dose of 3.6 mSv for the male reference phantom. The highest absorbed organ doses were observed in the kidneys (median of 0.175 mGy/MBq and 0.179 mGy/MBq for male and female reference phantom, respectively), followed by the red bone marrow (median of 0.044 mGy/MBq for male/female reference phantom) and the stomach wall (median of 0.060 and 0.062 mGy/MBq for male and female reference phantom, respectively). Conclusion: [⁶⁸Ga]Ga-RAYZ-8009 demonstrates a favorable biodistribution and dosimetry in patients with HCC.