MICCAI BraTS-METS 2026 — Task 1 checkpoints
Fine-tuned nnU-Net v2 checkpoints for brain metastases segmentation. Code, inference pipeline and full method description: https://github.com/thekeramik05/MICCAI-METS_challenge_bi-intel
Contents
weights.zip contains 7 fold checkpoints only:
| Model | Trainer | Folds |
|---|---|---|
| A ("Triad") | nnUNetTrainerBraTS_TriadInit_SmallLesionWeightedCE_CEw3__3_FT900 |
0–4 |
| B ("BrainIAC") | nnUNetTrainerBraTS_BrainIACWrapper_RCOversample__3 |
1, 3 |
plus the matching dataset.json / plans.json.
The Triad and BrainIAC foundation checkpoints are not redistributed here.
Obtain them from their authors and set TRIAD_CKPT / BRAINIAC_CKPT — see §3.1
of the GitHub README. BRAINIAC_CKPT is required at inference time as well as
during training.
What Model B actually contains
Model B checkpoints are not standalone nnU-Net weights. Each embeds a complete, frozen copy of the BrainIAC ViT-B/16 backbone:
| Module prefix | Parameters | Origin |
|---|---|---|
base_network.* |
88.2 M | nnU-Net, trained here |
brainiac.* |
116.7 M | BrainIAC ViT-B/16, verbatim |
proj.* |
3 K | projection layer, trained here |
| total | 204.9 M |
Model A contains no third-party weights: the Triad checkpoint initialised the encoder, which was then fully fine-tuned, leaving a plain 88.2 M nnU-Net.
Provenance
- BrainIAC — GitHub | Nature Neuroscience (2026)
- Triad — GitHub | Medical Image Analysis (2026)
- nnU-Net v2 — GitHub (Apache-2.0)
License
| Component | Terms |
|---|---|
| Model A checkpoints | Derived from Triad (MIT) — no additional restriction |
| Model B checkpoints | BrainIAC Research-Only License (see LICENSE) |
Because Model B embeds the BrainIAC backbone, use of these weights is permitted solely for non-commercial academic research and educational purposes. Commercial use — including clinical workflows, decision-support systems, healthcare operations, or any fee-bearing product or service — is prohibited without a separate written licence from Mass General Brigham, which reserves all commercial rights.