Purpose: The chemokine receptor CXCR4 is overexpressed in various types of human cancers. As a specific imaging agent of CXCR4, (68)Ga-NOTA-NFB was investigated in this study to assess its safety, biodistribution and dosimetry properties in healthy volunteers, and to preliminarily evaluate its application in glioma patients.
Methods: Six healthy volunteers underwent whole-body PET scans at 0, 0.5, 1, 2 and 3 h after (68)Ga-NOTA-NFB injection (mean dose, 182.4 ± 3.7 MBq (4.93 ± 0.10 mCi)). For time-activity curve calculations, 1 mL blood samples were obtained at 1, 3, 5, 10, 30, 60, 90, 120, 150 and 180 min after the injection. The estimated radiation doses were calculated by OLINDA/EXM software. Eight patients with glioma were enrolled and underwent both (68)Ga-NOTA-NFB and (18)F-FDG PET/CT scans before surgery. The expression of CXCR4 on the resected brain tumor tissues was determined by immunohistochemical staining.
Results: (68)Ga-NOTA-NFB was safe and well tolerated by all subjects. A rapid activity clearance from the blood circulation was observed. The organs with the highest absorbed doses were spleen (193.8 ± 32.5 μSv/MBq) and liver (119.3 ± 25.0 μSv/MBq). The mean effective dose was 25.4 ± 6.1 μSv/MBq. The maximum standardized uptake values (SUVmax) and the maximum target to non-target ratios (T/NTmax) of (68)Ga-NOTA-NFB PET/CT in glioma tissues were 4.11 ± 2.90 (range, 0.45-8.21) and 9.21 ± 8.75 (range, 3.66-24.88), respectively, while those of (18)F-FDG PET/CT were 7.34 ± 2.90 (range, 3.50-12.27) and 0.86 ± 0.41 (range, 0.35-1.59). The histopathological staining confirmed that CXCR4 was overexpressed on resected tumor tissues with prominent (68)Ga-NOTA-NFB uptake.
Conclusion: With a favorable radiation dosimetry profile, (68)Ga-NOTA-NFB is safe for clinical imaging. Compared to (18)F-FDG PET/CT, (68)Ga-NOTA-NFB PET/CT is more sensitive in detecting glioma and could have potential in diagnosing and treatment planning for CXCR4 positive patients.
Keywords: 68Ga-NOTA-NFB; CXCR4; PET/CT; glioma; internal dosimetry.