DistillPath-KS16-Virchow2
A 22M ViT-S/16 pathology tile encoder distilled from Virchow2 (632M ViT-H/14) into the kaiko ViT-S/16 student using backbone-token distillation on 6,000 public TCGA slides.
For the ImageNet-initialized variant, see DistillPath-IS16-Virchow2.
Paper: DistillPath: An Efficient 22M Distilled Pathology Encoder Approaching Large Foundation Model Performance Ramon Kaspar, Andrey Ignatov, Valentina Boeva. ETH Zurich. Published at the ECCV 2026 Workshop on Medical Foundation Models and Benchmarks (MedFM-Bench).
Model details
| Property | Value |
|---|---|
| Architecture | ViT-S/16 (vit_small_patch16_224 in timm) |
| Parameters | 21.7M |
| Feature dimension | 384 |
| Input size | 224 x 224 |
| Normalization | mean=(0.5, 0.5, 0.5), std=(0.5, 0.5, 0.5) |
| Student initialization | kaiko ViT-S/16 (pathology-pretrained) |
| Teacher | Virchow2 (632M, ViT-H/14, CC BY-NC-ND 4.0) |
| Training data | 6,000 TCGA H&E whole-slide images, 32 cohorts |
| Training steps | 50,000 (batch size 256, approx. 24-29 GPU-hours on 1x RTX 4090) |
Benchmark results
| Benchmark | DistillPath-KS16-Virchow2 | kaiko baseline | Virchow2 teacher |
|---|---|---|---|
| EVA mean (7 tasks) | 0.795 | 0.764 | 0.810 |
| HEST mean (9 tasks) | 0.371 | 0.349 | 0.398 |
| PLISM score | 0.447 | 0.307 | 0.447 |
See the paper for per-task results and comparisons with all four DistillPath variants.
Usage
Load directly from the Hub with timm:
import timm
model = timm.create_model(
"hf_hub:RamonK/DistillPath-KS16-Virchow2",
pretrained=True,
num_classes=0,
)
model.eval()
Or load manually:
import timm
from huggingface_hub import hf_hub_download
from safetensors.torch import load_file
model = timm.create_model("vit_small_patch16_224", pretrained=False, num_classes=0)
path = hf_hub_download("RamonK/DistillPath-KS16-Virchow2", "model.safetensors")
state_dict = load_file(path)
model.load_state_dict(state_dict, strict=True)
model.eval()
This model uses normalization mean=(0.5, 0.5, 0.5) and std=(0.5, 0.5, 0.5), inherited from the kaiko student. Apply this normalization to input tiles before inference:
from torchvision import transforms
transform = transforms.Compose([
transforms.Resize(224),
transforms.CenterCrop(224),
transforms.ToTensor(),
transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5]),
])
Distillation recipe
The recipe reads only the teacher's final class and patch tokens (no teacher pretraining heads required):
- Class-token loss: cosine distance + RKD (relational knowledge distillation)
- Patch-token loss: cosine distance after bicubic grid resizing (teacher 16x16 to student 14x14)
- Optimizer: AdamW, lr=1e-4, weight decay 0.05, cosine decay, 500 warmup steps
- Projector: DINO-style MLP (384 to 2048 to 2048 to 256 to d_t), discarded after training
Full details in the paper and the DistillPath repository.
License
This model is released under the Kaiko Non-Commercial Public License, inherited from the kaiko ViT-S/16 student weights. The Virchow2 teacher is released under CC BY-NC-ND 4.0. The distillation process used Virchow2 only to generate supervisory outputs; the released student contains no Virchow2 weights. This model is intended solely for non-commercial academic research.
Citation
@inproceedings{kaspar2026distillpath,
title = {DistillPath: An Efficient 22M Distilled Pathology Encoder Approaching Large Foundation Model Performance},
author = {Kaspar, Ramon and Ignatov, Andrey and Boeva, Valentina},
booktitle = {Medical Foundation Models and Benchmarks (MedFM-Bench), ECCV 2026},
year = {2026}
}