Hepatobiliary PET with [68Ga]Ga-BP-IDA - preclinical evaluation and its translational potential for liver function monitoring.

Background: The aim of this study was to investigate the preclinical biodistribution and molecular pathway of [⁶⁸Ga]Ga-BP-IDA and to evaluate its clinical suitability for quantitative monitoring of liver function during transarterial radioembolization (TARE) therapy of a hepatocellular carcinoma (HCC).

Results: [⁶⁸Ga]Ga-BP-IDA undergoes hepatobiliary clearance, with uptake into hepatocytes via OATP1B1 and OATP1B3. [⁶⁸Ga]Ga-BP-IDA exhibits demetallation in vivo but is nevertheless suitable for clinical application due to its rapid uptake into functional liver tissue. In a clinical case [⁶⁸Ga]Ga-BP-IDA PET/CT allowed for differentiation of functional liver mass from cancerous tissue and enabled monitoring the effect on liver and tumor volume as well as on residual liver function after TARE therapy. Following TARE treatment, a reduction of the hepatic uptake rate was observed in both non-cancerous liver lobes, but was more pronounced in the right lobe, indicating a correlation to the higher non-targeted radiation dose from the TARE treatment in this lobe. [⁶⁸Ga]Ga-BP-IDA PET/CT thus revealed additional information on liver function impairment which was not represented by CT-based volumetry alone.

Conclusion: [⁶⁸Ga]Ga-BP-IDA PET/CT is a suitable tool for planning and monitoring TARE therapy of primary liver tumors and may complement the limits of volumetry-based methods with functional information about the liver.