# Neuro-oncology imaging roadmap: FDG PET → amino acid PET → SSTR2 theranostics in meningioma

Source: https://nuclide.cc/roadmaps/neuro-imaging-roadmap/  
Nuclide record `neuro-imaging-roadmap` (Roadmap). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

Ordinary sugar-based PET scans do not work well in the brain because healthy brain tissue itself uses a lot of sugar. Nuclear medicine had to develop tracers that light up brain tumours specifically, first amino acid tracers for gliomas and then a receptor tracer that also opens the door to a matched radioactive treatment for meningioma.

## Summary

FDG PET has a structural limitation in the brain: normal grey matter has high baseline glucose uptake, so FDG contrast between tumour and healthy brain tissue is poor, unlike its performance in most body cancers. This drove development from the 1980s onward of radiolabelled amino acid tracers, principally 11C-methionine and later 18F-FET, which exploit the increased amino acid transport of tumour cells against a low physiological background in normal brain.

These tracers were gradually adopted into formal guidance: the PET-RANO working group and EANO published evidence-based recommendations for PET imaging in gliomas in 2016, followed by the joint EANM/EANO/RANO/SNMMI practice guideline (version 1.0) for glioma PET imaging with radiolabelled amino acids and FDG, published in 2019, standardising acquisition and interpretation (for example, a tumour-to-brain ratio threshold of 1.6-1.8 for 18F-FET). An updated RANO/EANO policy review in 2025 strengthened several of these recommendations, including for delineating tumour extent and distinguishing recurrence from treatment-related change.

A parallel and largely separate strand targets meningioma, a tumour that (unlike most gliomas) reliably overexpresses somatostatin receptor 2 (SSTR2). Rachinger et al. (2015) showed that 68Ga-DOTATATE PET uptake correlates with SSTR2 expression and outperforms MRI sensitivity (90% vs 79%) for discriminating meningioma from tumour-free tissue, and it is now used for surgical and radiotherapy planning, particularly at the skull base. Because meningioma expresses the same target as neuroendocrine tumours, it has become a candidate for the same theranostic pairing: a phase 1/2 trial of the alpha emitter 225Ac-DOTATATE (RYZ101) in progressive or recurrent intracranial meningioma opened at Ohio State, testing whether the SSTR theranostic model developed for neuroendocrine tumours extends into neuro-oncology.

## Fields

- Kind: Roadmap
- Last checked: 2026-09-22

## Sources

- Rachinger et al., increased 68Ga-DOTATATE uptake discriminates meningioma and tumour-free tissue (J Nucl Med 2015): https://pubmed.ncbi.nlm.nih.gov/25635133/
- Joint EANM/EANO/RANO practice guidelines/SNMMI procedure standards for glioma PET, version 1.0 (2019): https://pmc.ncbi.nlm.nih.gov/articles/PMC6351513/
- Update to the RANO working group and EANO recommendations for PET imaging in gliomas (Lancet Oncology 2025): https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(25)00193-7/fulltext
- ClinicalTrials.gov: RYZ101 for progressive/recurrent intracranial meningioma (NCT07150806): https://clinicaltrials.gov/study/NCT07150806

## Connected records

- isotopes: [Actinium-225](https://nuclide.cc/isotopes/ac-225/), [Carbon-11](https://nuclide.cc/isotopes/c-11/), [Fluorine-18](https://nuclide.cc/isotopes/f-18/), [Gallium-68](https://nuclide.cc/isotopes/ga-68/)
- indications: [Glioma & glioblastoma](https://nuclide.cc/indications/glioblastoma/), [Meningioma](https://nuclide.cc/indications/meningioma/)
- technologies: [Astatine-211 alpha therapy](https://nuclide.cc/technologies/astatine-211-alpha-therapy/), [FDG PET](https://nuclide.cc/technologies/fdg-pet/), [PET (positron emission tomography)](https://nuclide.cc/technologies/pet/), [PET/CT](https://nuclide.cc/technologies/pet-ct/), [Somatostatin receptor PET (68Ga/64Cu-DOTATATE)](https://nuclide.cc/technologies/sstr-pet/)
- targets: [Somatostatin receptor 2](https://nuclide.cc/targets/sstr2/)
- drugs: [Actinium-225 DOTATATE](https://nuclide.cc/drugs/ryz101/), [Fludeoxyglucose F-18 (FDG)](https://nuclide.cc/drugs/fludeoxyglucose-f18/), [Gallium-68 DOTATATE (and Cu-64 DOTATATE)](https://nuclide.cc/drugs/ga68-dotatate/)

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