Biodistribution and Dosimetry Evaluation of the Radiolabeled Somatostatin Receptor Antagonist 68Ga-DATA5m LM4 in Molecular Imaging of Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors Patients.

Purpose: This study aimed to assess the biodistribution and radiation dosimetry of 68Ga-DATA5m LM4 in patients with gastroenteropancreatic neuroendocrine tumors.

Patients And Methods: Eight patients (5 females and 3 males) with various gastroenteropancreatic neuroendocrine tumors were included in the study. Each patient underwent 3 whole-body PET scans at 10, 60, and 120 minutes after receiving an IV injection of approximately 162.5 MBq of 68Ga-DATA5m LM4. Organs considered for dosimetric analysis included the liver, heart, spleen, kidneys, adrenal glands, and lumbar vertebrae (L2 to L4). Dosimetric calculations were performed using the OLINDA/EXM 2.2 software.

Results: Physiological uptake of 68Ga-DATA5m LM4 was observed in the pituitary gland, spleen, liver, adrenal glands, and the urinary tract (kidneys and urinary bladder) for all patients. The kidneys received the highest absorbed doses at (4.77E-02 ± 1.49E-02 mSv/MBq). The mean effective dose was 2.61E-03 ± 5.99E-04 mSv/MBq.

Conclusions: 68Ga-DATA5m LM4 injection is safe and is primarily excreted through urine, delivering the highest radiation dose to the kidneys.