Head-to-Head Comparison of [⁶⁸Ga]Ga-DOTATATE PET/CT and [⁶⁸Ga]Ga-NODAGA-LM3 PET/CT

This study compared the physiologic distribution of [⁶⁸Ga]Ga-DOTATATE and [⁶⁸Ga]Ga-NODAGA-LM3 PET/CT, assessed SUV and tumor-to-background ratio (TBR) measurements in primary and metastatic lesions, and evaluated lesion detection performance. Methods: Forty-one adult patients with well-differentiated (G1-G3) gastroenteropancreatic or lung neuroendocrine neoplasms, pheochromocytoma, medullary thyroid carcinoma, and well-differentiated thyroid carcinoma were included in this study. All patients underwent PET/CT imaging with both [⁶⁸Ga]Ga-DOTATATE and [⁶⁸Ga]Ga-NODAGA-LM3 within a 3-d interval. SUV_max and SUV_mean were calculated for physiologic uptake regions, and SUV_max and TBR were determined for lesions. Paired data were analyzed using the paired-samples t test or Wilcoxon signed-rank test, with a P of less than 0.05 considered statistically significant. Results: The median patient age was 62 y (range, 27-90 y), and 63.4% were women. Analysis of uptake in normal organs revealed that [⁶⁸Ga]Ga-DOTATATE PET/CT demonstrated significantly higher physiologic activity in the liver, spleen, pancreas, and jejunum, whereas [⁶⁸Ga]Ga-NODAGA-LM3 showed significantly higher uptake in the parotid glands, mediastinal blood pool, lungs, breasts, kidneys, and uterus. Lesion-based analysis found that [⁶⁸Ga]Ga-NODAGA-LM3 detected significantly more liver metastases than did [⁶⁸Ga]Ga-DOTATATE (P < 0.05), with no significant differences observed in other regions. The TBR of liver metastases was significantly higher with [⁶⁸Ga]Ga-NODAGA-LM3 (P = 0.006), although the SUV_max did not significantly differ between radiotracers. Conclusion: [⁶⁸Ga]Ga-NODAGA-LM3 demonstrates a higher TBR and superior detection of liver metastases compared with [⁶⁸Ga]Ga-DOTATATE. Although no significant differences were found in other regions, the 2 radiotracers exhibit distinct physiologic distribution patterns.