Head-to-Head Comparison of [18F]MFBG and [68Ga]Ga-DOTA-TATE PET/CT in Suspected Recurrent/Refractory Neuroblastoma: Prospective Single-center Analysis

Introduction: To prospectively compare the diagnostic value of 18 F-meta-fluorobenzylguanidine ([ 18 F]MFBG) and [ 68 Ga]Ga-DOTA-TATE PET/CT in pediatric patients with suspected recurrent/refractory neuroblastoma. Methods: Between December 2024 and March 2025, 28 children (18 boys, 10 girls; mean age ± SD 4.8 ± 2.5 y) underwent both tracers within 1 week at a single institution. Physiological biodistribution, image quality, lesion conspicuity, semiquantitative uptake (SUVmax), Curie score, and response classification were analyzed side-by-side. Results: [ 18 F]MFBG showed higher background than [ 68 Ga]Ga-DOTA-TATE in skeletal muscle but lower activity in articular metaphyses, pituitary, and kidneys. Heterogeneous distribution of [ 18 F]MFBG was more common in the liver, while notable uptake differences were observed in the pancreas with [ 68 Ga]Ga-DOTA-TATE. Patient-level concordance was high (both scans positive in 15, negative in 7); discordance occurred in 6 patients (2 MFBG+/DOTA-TATE-, 4 MFBG-/DOTA-TATE+). Region-level analysis encompassed 86 relapsed or metastatic regions in 17 patients. [ 18 F]MFBG detected 80 regions (sensitivity 93.0%, specificity 96.4%, AUC 0.947), whereas [ 68 Ga]Ga-DOTA-TATE detected 82 (sensitivity 95.4%, specificity 86.6%, AUC 0.910). Superior specificity of [ 18 F]MFBG stemmed largely from its higher uptake in bone/marrow metastases compared with [ 68 Ga]Ga-DOTA-TATE (median SUVmax 5.21 vs. 2.90, P <0.0001). Region-level concordance revealed 78 concordant positive sites and 39 discordant sites (9 MFBG+/DOTA-TATE-, 30 MFBG-/DOTA-TATE+). Aggregate Curie scores were identical (155 each). Because uptake patterns were complementary, combining both tracers improved visual confidence in heterogeneous tumors and refined treatment-response categorization. Conclusions: [ 18 F]MFBG and [ 68 Ga]Ga-DOTA-TATE PET/CT imaging are effective for evaluating relapsed or metastatic neuroblastoma because they show lower uptake in normal organs and benign lesions. The 2 imaging modalities offer complementary value in tumor detection and assessment of treatment response due to tumor spatial heterogeneity.