Article Summary
F-18 mFBG PET/CT imaging shows significantly superior diagnostic performance compared to the current gold-standard I-123 MIBG SPECT/CT for neuroblastoma detection, achieving 97% patient-level sensitivity and 99% lesion-level sensitivity, and may become the preferred imaging standard for staging and monitoring this rare pediatric tumor.
- Superior Sensitivity: F-18 mFBG achieved 97% sensitivity on a per-patient basis and 99% on a per-lesion basis, compared to 82% and 52% respectively for I-123 MIBG
- Equal Specificity: Both tracers demonstrated identical 82% specificity, indicating comparable accuracy in ruling out disease
- Faster Procedure: F-18 mFBG PET/CT eliminates the time-consuming 2-day procedure requirement of current standard imaging
- Better Bone Detection: The newer tracer detected significantly more lesions in bone, the most common site of metastatic neuroblastoma
- Next Steps: Clinical implementation requires larger prospective trials, cost-effectiveness analyses, and improved tracer availability
PET/CT scans with a new F-18-labeled radiotracer that targets neuroblastoma may become a superior, more efficient alternative to standard techniques for staging and response assessment, according to a recent study.
The finding is from a comparison between F-18 meta-fluorobenzylguanidine (mFBG) scans and current gold-standard I-123 metaiodobenzylguanidine (MIBG) scans among 115 patients with 1,644 lesions, with mFBG PET/CT showing superior diagnostic performance, noted lead author Domenico Albano, of the University of Brescia in Italy, and colleagues.
“F-18 mFBG PET/CT could be considered in the future as a potential replacement of I-123 MIBG SPECT/CT as the imaging gold standard due to its superior diagnostic performance and logistical advantages,” the group wrote. The study was published July 8 in Pediatric Radiology.
Neuroblastoma is a rare pediatric tumor that arises from the sympathetic nervous system, with long-term survival rates hovering around 40–50% for patients with metastases at diagnosis, the authors explained. While I-123 MIBG SPECT/CT is considered the gold standard for evaluation, it presents some limitations, such as the time-consuming procedure (2 days), the low spatial resolution, and challenging interpretation, they noted.
Alternatively, F-18 mFBG PET/CT has shown high detectability in several original studies, and in this study the researchers aimed to provide more solid data on its use with a pooled analysis that compared the tracers head-to-head.
The group searched three databases through November 2025 for studies directly comparing F-18 mFBG and I-123 MIBG in the same patients and found five that met their criteria for inclusion. Diagnostic accuracy was calculated separately on a per-patient and per-lesion basis using a bivariate random-effects statistical model.
On a per-patient basis, F-18 mFBG achieved a pooled sensitivity of 97%, compared with 82% for I-123 MIBG, with identical specificity of 82% for both tracers. The gap widened in the lesion-based analysis, where F-18 mFBG's sensitivity reached 99% versus 52% for I-123 MIBG, with most additional lesions detected by PET occurring in bone. Three of the five studies also found higher Curie scores, a standardized measure of disease burden, with the newer tracer.
“Our qualitative and quantitative research showed that there are no significant differences in terms of specificity among F-18 mFBG PET/CT and I-123 MIBG SPECT/CT in neuroblastoma patients, while the difference in terms of sensitivity was significant,” the group wrote.
The authors noted that head-to-head comparisons of molecular imaging techniques employing different tracers, when based solely on diagnostic performance, represent only the starting point of a broader and more comprehensive evaluation. The impact of a diagnostic test should be assessed across multiple domains, including technical characteristics, availability, diagnostic performance, influence on clinical decision-making, effects on patient outcomes, and cost-effectiveness, they wrote.
“[F-18 mFBG's] routine clinical implementation will depend on larger prospective trials, cost-effectiveness analyses, and wider tracer availability,” the researchers concluded.
The full study is available here.
