Paediatric Neuroblastoma Imaging with [18F]MFBG LAFOV PET/CT

Neuroblastoma, the most common extracranial solid tumour in children, poses significant diagnostic and therapeutic challenges. Traditionally, meta-[123I]iodobenzylguanidine ([123I]MIBG) scintigraphy with SPECT/CT has been the gold standard for diagnosing and monitoring this malignancy. However, advancements in imaging technology have introduced the meta-[18F]fluorobenzylguanidine ([18F]MFBG) PET/CT with a long-axial field-of-view (LAFOV), offering a more sensitive and less invasive alternative. A recent article published in the Journal of Nuclear Medicine explores the feasibility and clinical benefits of [18F]MFBG LAFOV PET/CT compared to [123I]MIBG SPECT/CT in paediatric neuroblastoma imaging.

One of the primary advantages of [18F]MFBG LAFOV PET/CT is its significantly shorter scan time and eliminating the need for sedation or general anaesthesia (GA) in most paediatric patients. The traditional [123I]MIBG SPECT/CT requires a 24-hour post-injection waiting period, followed by a scan time exceeding two hours, which often necessitates GA, particularly in younger children. In contrast, [18F]MFBG PET/CT can be performed within one hour post-injection, with a scan time as short as 5 to 10 minutes. This reduction in scan time minimises the stress and discomfort for the child and reduces the overall radiation exposure due to the ultra-low-dose CT protocol.

Furthermore, [18F]MFBG, being labelled with fluorine-18, provides higher-resolution images and greater sensitivity in detecting neuroblastoma lesions compared to [123I]MIBG. In clinical studies, [18F]MFBG PET/CT identified more radiotracer-avid lesions in 80% of the cases compared to [123I]MIBG SPECT/CT. This increased detection rate is particularly significant in areas like the bone marrow, retroperitoneal lymph nodes, and intraspinal regions, where traditional imaging methods may fall short. The ability to detect these lesions with greater accuracy can have profound implications for staging and treatment planning in neuroblastoma patients.

Feasibility of Implementing [18F]MFBG LAFOV PET/CT in Clinical Practice

Implementing [18F]MFBG LAFOV PET/CT in routine clinical practice appears to be highly feasible, as demonstrated by the pilot study conducted at Rigshospitalet, Copenhagen University Hospital. The study involved ten paediatric patients and highlighted several logistical and clinical benefits. Notably, none of the children required sedation or GA during the [18F]MFBG PET/CT scan, thanks to the short acquisition time and the high sensitivity of the LAFOV PET/CT scanner. This was in stark contrast to the [123I]MIBG SPECT/CT scans, where 80% of the children needed GA.

The study also showcased the practical aspects of producing [18F]MFBG tracers in-house, ensuring that the procedure could be seamlessly integrated into existing nuclear medicine departments. The tracer synthesis was automated and complied with good manufacturing practices, with the radiochemical purity exceeding 98%. The ability to prepare the tracer on-site not only reduces costs but also ensures the availability of fresh tracers for timely imaging.

Clinical Implications of [18F]MFBG LAFOV PET/CT

The clinical implications of adopting [18F]MFBG LAFOV PET/CT are substantial. This imaging technique's increased sensitivity and resolution could lead to more accurate staging and better treatment response assessments, potentially altering therapeutic strategies. For instance, the study reported higher SIOPEN and Curie scores in 50% and 70% of cases, respectively, when using [18F]MFBG PET/CT compared to [123I]MIBG SPECT/CT. These scores are critical in determining the extent of disease and guiding treatment decisions.

Moreover, the ability to conduct the entire imaging process in one day, without the need for GA, enhances the overall patient experience and reduces the burden on healthcare resources. The shorter protocol and improved diagnostic accuracy may also facilitate more frequent monitoring of disease progression or response to treatment, allowing for more timely adjustments to therapy.

Conclusion

The introduction of [18F]MFBG LAFOV PET/CT represents a significant advancement in paediatric neuroblastoma imaging. Its advantages over [123I]MIBG SPECT/CT, including shorter scan times, avoidance of GA, and higher lesion detection rates, underscore its potential to become the new standard of care. The feasibility of implementing this technique in clinical practice has been demonstrated, and its impact on patient outcomes is promising. Future studies with larger cohorts are warranted to further validate these findings and explore the full clinical potential of [18F]MFBG LAFOV PET/CT in managing neuroblastoma.

Source: Journal of Nuclear Medicine

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