Biodistribution and Radiation Dosimetry for [⁶⁸Ga]Ga-LNTH-1363S, a Probe Targeting Fibroblast Activation Protein α

Area of Science:

• Nuclear Medicine
• Radiochemistry
• Oncology

Background:

• Fibroblast Activation Protein (FAP) is a key target in cancer imaging.
• [68Ga]Ga-LNTH-1363S is a novel positron emission tomography (PET) tracer designed for FAP targeting.

Purpose of the Study:

• To evaluate the PET biodistribution and radiation dosimetry of [68Ga]Ga-LNTH-1363S in cancer patients.
• To assess the safety and efficacy of this new FAP-targeted tracer.

Main Methods:

• Five cancer patients received [68Ga]Ga-LNTH-1363S (153-184 MBq) intravenously.
• PET/CT imaging was performed at 10, 60, and 180 minutes post-injection.
• Radiation dosimetry was calculated using the MIRD formalism, and SUV analysis was conducted.

Main Results:

• The tracer showed rapid tumor uptake and efficient clearance from non-target tissues, yielding high tumor-to-background ratios.
• The kidneys received the highest absorbed dose (0.038 ± 0.01 mGy/MBq).
• Tumor SUVmax peaked at 10 minutes (18.6 ± 7.2) and remained high; effective dose was 0.013 ± 0.002 mSv/MBq.

Conclusions:

• [68Ga]Ga-LNTH-1363S exhibits favorable biodistribution and dosimetry profiles for PET imaging.
• Its performance is comparable to other FAP-targeted tracers.
• The tracer is a promising candidate for FAP-targeted cancer imaging.