---
license: mit
tags:
- medical
- cancer
- ct-scan
- risk-prediction
- healthcare
- pytorch
- vision
datasets:
- NLST
metrics:
- auc
- c-index
language:
- en
library_name: transformers
pipeline_tag: image-classification
---

# Sybil - Lung Cancer Risk Prediction

## 🎯 Model Description

Sybil is a validated deep learning model that predicts future lung cancer risk from a single low-dose chest CT (LDCT) scan. Published in the Journal of Clinical Oncology, this model can assess cancer risk over a 1-6 year timeframe.

### Key Features
- **Single Scan Analysis**: Requires only one LDCT scan
- **Multi-Year Prediction**: Provides risk scores for years 1-6
- **Validated Performance**: Tested across multiple institutions globally
- **Ensemble Approach**: Uses 5 models for robust predictions

## 🚀 Quick Start

### Installation

```bash
pip install huggingface-hub torch torchvision pydicom
```

### Basic Usage

```python
from huggingface_hub import snapshot_download
import sys
import os

# Download model
model_path = snapshot_download(repo_id="Lab-Rasool/sybil")
sys.path.append(model_path)

# Import model
from modeling_sybil_hf import SybilHFWrapper
from configuration_sybil import SybilConfig

# Initialize
config = SybilConfig()
model = SybilHFWrapper(config)

dicom_dir = "path/to/volume"
dicom_paths = [os.path.join(dicom_dir, f) for f in os.listdir(dicom_dir) if f.endswith('.dcm')]

print(f"Found {len(dicom_paths)} DICOM files for prediction.")

# Get predictions
output = model(dicom_paths=dicom_paths)
risk_scores = output.risk_scores.numpy()

# Display results
print("\nLung Cancer Risk Predictions:")
print(f"Risk scores shape: {risk_scores.shape}")

# Handle both single and batch predictions
if risk_scores.ndim == 2:
    # Batch predictions - take first sample
    risk_scores = risk_scores[0]

for i, score in enumerate(risk_scores):
    print(f"Year {i+1}: {float(score)}")

```

## 📊 Example with Demo Data

```python
import requests
import zipfile
from io import BytesIO
import os

# Download demo DICOM files
def get_demo_data():
    cache_dir = os.path.expanduser("~/.sybil_demo")
    demo_dir = os.path.join(cache_dir, "sybil_demo_data")

    if not os.path.exists(demo_dir):
        print("Downloading demo data...")
        url = "https://www.dropbox.com/scl/fi/covbvo6f547kak4em3cjd/sybil_example.zip?rlkey=7a13nhlc9uwga9x7pmtk1cf1c&dl=1"
        response = requests.get(url)

        os.makedirs(cache_dir, exist_ok=True)
        with zipfile.ZipFile(BytesIO(response.content)) as zf:
            zf.extractall(cache_dir)

    # Find DICOM files
    dicom_files = []
    for root, dirs, files in os.walk(cache_dir):
        for file in files:
            if file.endswith('.dcm'):
                dicom_files.append(os.path.join(root, file))

    return sorted(dicom_files)

# Run demo
from huggingface_hub import snapshot_download
import sys

# Load model
model_path = snapshot_download(repo_id="Lab-Rasool/sybil")
sys.path.append(model_path)

from modeling_sybil_wrapper import SybilHFWrapper
from configuration_sybil import SybilConfig

# Initialize and predict
config = SybilConfig()
model = SybilHFWrapper(config)

dicom_files = get_demo_data()
output = model(dicom_paths=dicom_files)

# Show results
for i, score in enumerate(output.risk_scores.numpy()):
    print(f"Year {i+1}: {float(score)}")
```

## 🔬 Advanced Usage: Embedding Extraction

### Extract Embeddings Before Dropout Layer

You can extract 512-dimensional embedding vectors from the layer immediately before the dropout layer. This captures the learned risk features before the final prediction layer.

```python
from huggingface_hub import snapshot_download
import sys
import os
import torch
import numpy as np

# Download and setup model
model_path = snapshot_download(repo_id="Lab-Rasool/sybil")
sys.path.append(model_path)

from modeling_sybil_hf import SybilHFWrapper
from configuration_sybil import SybilConfig

def extract_embeddings(dicom_paths):
    """
    Extract embeddings from the layer after ReLU, before Dropout.

    Args:
        dicom_paths: List of DICOM file paths

    Returns:
        numpy array of shape (512,) - averaged embeddings across ensemble
    """
    # Initialize model
    config = SybilConfig()
    model = SybilHFWrapper(config)

    # Set each model in ensemble to eval mode
    for m in model.models:
        m.eval()

    # Storage for embeddings from each model in ensemble
    all_embeddings = []

    # Register hooks on each model in the ensemble
    for model_idx, ensemble_model in enumerate(model.models):
        embeddings_buffer = []

        def create_hook(buffer):
            def hook(module, input, output):
                # Capture the output of ReLU layer (before dropout)
                buffer.append(output.detach().cpu())
            return hook

        # Register hook on the ReLU layer
        hook_handle = ensemble_model.relu.register_forward_hook(create_hook(embeddings_buffer))

        # Run forward pass
        with torch.no_grad():
            _ = model(dicom_paths=dicom_paths)

        # Remove hook
        hook_handle.remove()

        # Get the embeddings (should be shape [1, 512])
        if embeddings_buffer:
            embedding = embeddings_buffer[0].numpy().squeeze()
            all_embeddings.append(embedding)
            print(f"Model {model_idx + 1}: Embedding shape = {embedding.shape}")

    # Average embeddings across ensemble
    averaged_embedding = np.mean(all_embeddings, axis=0)
    return averaged_embedding

# Usage
dicom_dir = "path/to/volume"
dicom_paths = [os.path.join(dicom_dir, f) for f in os.listdir(dicom_dir) if f.endswith('.dcm')]

embeddings = extract_embeddings(dicom_paths)
print(f"\nEmbedding vector shape: {embeddings.shape}")
print(f"Embedding statistics:")
print(f"  Mean: {np.mean(embeddings):.6f}")
print(f"  Std: {np.std(embeddings):.6f}")
print(f"  Min: {np.min(embeddings):.6f}")
print(f"  Max: {np.max(embeddings):.6f}")
```

## 🎯 Extracting Embeddings at Other Layers

### Available Extraction Points

The Sybil model has several key layers where you can extract intermediate representations:

```python
import torch
from huggingface_hub import snapshot_download
import sys

model_path = snapshot_download(repo_id="Lab-Rasool/sybil")
sys.path.append(model_path)

from modeling_sybil_hf import SybilHFWrapper
from configuration_sybil import SybilConfig

config = SybilConfig()
model = SybilHFWrapper(config)

# Get first model from ensemble for demonstration
first_model = model.models[0]

# Model architecture flow:
# Input → image_encoder → pool → relu → dropout → prob_of_failure_layer → Output

def extract_layer_output(model, layer_name, dicom_paths):
    """
    Extract output from any layer in the model.

    Args:
        model: SybilHFWrapper model
        layer_name: Name of the layer to extract from
        dicom_paths: List of DICOM file paths

    Returns:
        Extracted features from the specified layer
    """
    features = []

    def hook_fn(module, input, output):
        features.append(output.detach().cpu())

    # Register hook on the specified layer
    for m in model.models:
        layer = dict(m.named_modules())[layer_name]
        hook_handle = layer.register_forward_hook(hook_fn)

    # Run forward pass
    with torch.no_grad():
        _ = model(dicom_paths=dicom_paths)

    # Remove hook
    hook_handle.remove()

    return features

# Example 1: Extract from image encoder (3D feature maps)
# Shape: (batch, 512, time, height, width)
encoder_features = extract_layer_output(model, 'image_encoder', dicom_paths)
print(f"Image encoder output shape: {encoder_features[0].shape}")

# Example 2: Extract from pooling layer (before ReLU)
# Shape: (batch, 512)
pool_features = extract_layer_output(model, 'pool', dicom_paths)
print(f"Pool layer output shape: {pool_features[0].shape}")

# Example 3: Extract from ReLU layer (before dropout) - RECOMMENDED
# Shape: (batch, 512)
relu_features = extract_layer_output(model, 'relu', dicom_paths)
print(f"ReLU layer output shape: {relu_features[0].shape}")

# Example 4: Extract from dropout layer (before final prediction)
# Shape: (batch, 512)
dropout_features = extract_layer_output(model, 'dropout', dicom_paths)
print(f"Dropout layer output shape: {dropout_features[0].shape}")
```

### Custom Layer Extraction Template

```python
def extract_custom_layer(dicom_paths, target_layer_name):
    """
    Template for extracting features from any layer.

    Args:
        dicom_paths: List of DICOM file paths
        target_layer_name: Name of target layer (e.g., 'relu', 'pool', 'image_encoder')

    Returns:
        Extracted features averaged across ensemble
    """
    from huggingface_hub import snapshot_download
    import sys
    import torch
    import numpy as np

    model_path = snapshot_download(repo_id="Lab-Rasool/sybil")
    sys.path.append(model_path)

    from modeling_sybil_hf import SybilHFWrapper
    from configuration_sybil import SybilConfig

    config = SybilConfig()
    model = SybilHFWrapper(config)

    all_features = []

    for ensemble_model in model.models:
        ensemble_model.eval()
        features_buffer = []

        # Get the target layer
        target_layer = dict(ensemble_model.named_modules())[target_layer_name]

        # Register hook
        def hook(module, input, output):
            features_buffer.append(output.detach().cpu())

        hook_handle = target_layer.register_forward_hook(hook)

        # Forward pass
        with torch.no_grad():
            _ = model(dicom_paths=dicom_paths)

        hook_handle.remove()

        if features_buffer:
            all_features.append(features_buffer[0])

    # Average across ensemble
    averaged_features = torch.stack(all_features).mean(dim=0)
    return averaged_features.numpy()
```

## 🔍 Model Architecture Inspection

### Print Full Model Architecture

```python
from huggingface_hub import snapshot_download
import sys

model_path = snapshot_download(repo_id="Lab-Rasool/sybil")
sys.path.append(model_path)

from modeling_sybil_hf import SybilHFWrapper
from configuration_sybil import SybilConfig

config = SybilConfig()
model = SybilHFWrapper(config)

# Print configuration
print("=" * 80)
print("MODEL CONFIGURATION:")
print("=" * 80)
print(config)

# Print ensemble information
print("\n" + "=" * 80)
print("ENSEMBLE INFORMATION:")
print("=" * 80)
print(f"Number of models in ensemble: {len(model.models)}")
print(f"Device: {model.device}")

# Print architecture of first model
print("\n" + "=" * 80)
print("MODEL ARCHITECTURE (First model in ensemble):")
print("=" * 80)
first_model = model.models[0]
print(first_model)
```

### Count Model Parameters

```python
from huggingface_hub import snapshot_download
import sys

model_path = snapshot_download(repo_id="Lab-Rasool/sybil")
sys.path.append(model_path)

from modeling_sybil_hf import SybilHFWrapper
from configuration_sybil import SybilConfig

config = SybilConfig()
model = SybilHFWrapper(config)

print("=" * 80)
print("MODEL PARAMETERS:")
print("=" * 80)

# Parameters per model in ensemble
for i, ensemble_model in enumerate(model.models):
    total_params = sum(p.numel() for p in ensemble_model.parameters())
    trainable_params = sum(p.numel() for p in ensemble_model.parameters() if p.requires_grad)

    print(f"\nModel {i+1}:")
    print(f"  Total parameters: {total_params:,}")
    print(f"  Trainable parameters: {trainable_params:,}")
    print(f"  Non-trainable parameters: {total_params - trainable_params:,}")

# Total ensemble parameters
total_ensemble = sum(
    sum(p.numel() for p in m.parameters())
    for m in model.models
)
print(f"\nTotal ensemble parameters: {total_ensemble:,}")
```

### List Model Components

```python
from huggingface_hub import snapshot_download
import sys

model_path = snapshot_download(repo_id="Lab-Rasool/sybil")
sys.path.append(model_path)

from modeling_sybil_hf import SybilHFWrapper
from configuration_sybil import SybilConfig

config = SybilConfig()
model = SybilHFWrapper(config)
first_model = model.models[0]

print("=" * 80)
print("MODEL COMPONENTS:")
print("=" * 80)

# Print each component with parameter count
for name, module in first_model.named_children():
    num_params = sum(p.numel() for p in module.parameters())
    print(f"{name}: {module.__class__.__name__} ({num_params:,} parameters)")

print("\n" + "=" * 80)
print("DETAILED LAYER NAMES:")
print("=" * 80)

# Print all named modules (including nested layers)
for name, module in first_model.named_modules():
    if name:  # Skip the root module
        print(f"  {name}: {module.__class__.__name__}")
```

### Model Architecture Overview

The Sybil model consists of the following key components:

```
Input (3D CT Volume)
    ↓
image_encoder (R3D-18 backbone)
    - 3D convolutional neural network
    - Pretrained on Kinetics-400
    - Output: (batch, 512, time, height, width)
    ↓
pool (MultiAttentionPool)
    - Attention-based pooling mechanisms
    - Combines multiple pooling strategies
    - Output: (batch, 512)
    ↓
relu (ReLU activation)
    - Non-linear activation
    - Output: (batch, 512) ← EMBEDDING EXTRACTION POINT
    ↓
dropout (Dropout layer)
    - Regularization (p=0.0 in inference)
    - Output: (batch, 512)
    ↓
prob_of_failure_layer (CumulativeProbabilityLayer)
    - Hazard function prediction
    - Output: (batch, 6) - one score per year
    ↓
sigmoid (applied post-forward)
    ↓
Risk Scores (final output)
```

### Get Layer-by-Layer Summary

```python
def print_model_summary(model):
    """Print a detailed summary of the model architecture."""
    from huggingface_hub import snapshot_download
    import sys

    model_path = snapshot_download(repo_id="Lab-Rasool/sybil")
    sys.path.append(model_path)

    from modeling_sybil_hf import SybilHFWrapper
    from configuration_sybil import SybilConfig

    config = SybilConfig()
    model = SybilHFWrapper(config)
    first_model = model.models[0]

    print(f"{'Layer Name':<40} {'Type':<30} {'Parameters':>15}")
    print("=" * 85)

    total_params = 0
    for name, module in first_model.named_modules():
        if name:  # Skip root
            num_params = sum(p.numel() for p in module.parameters())
            if num_params > 0:
                print(f"{name:<40} {module.__class__.__name__:<30} {num_params:>15,}")
                total_params += num_params

    print("=" * 85)
    print(f"{'TOTAL':<40} {'':<30} {total_params:>15,}")

# Usage
print_model_summary(model)
```

## 📈 Performance Metrics

| Dataset | 1-Year AUC | 6-Year AUC | Sample Size |
|---------|------------|------------|-------------|
| NLST Test | 0.94 | 0.86 | ~15,000 |
| MGH | 0.86 | 0.75 | ~12,000 |
| CGMH Taiwan | 0.94 | 0.80 | ~8,000 |

## 🏥 Intended Use

### Primary Use Cases
- Risk stratification in lung cancer screening programs
- Research on lung cancer prediction models
- Clinical decision support (with appropriate oversight)

### Users
- Healthcare providers
- Medical researchers
- Screening program coordinators

### Out of Scope
- ❌ Diagnosis of existing cancer
- ❌ Use with non-LDCT imaging (X-rays, MRI)
- ❌ Sole basis for clinical decisions
- ❌ Use outside medical supervision

## 📋 Input Requirements

- **Format**: DICOM files from chest CT scan
- **Type**: Low-dose CT (LDCT)
- **Orientation**: Axial view
- **Order**: Anatomically ordered (abdomen → clavicles)
- **Number of slices**: Typically 100-300 slices
- **Resolution**: Automatically handled by model

## ⚠️ Important Considerations

### Medical AI Notice
This model should **supplement, not replace**, clinical judgment. Always consider:
- Complete patient medical history
- Additional risk factors (smoking, family history)
- Current clinical guidelines
- Need for professional medical oversight

### Limitations
- Optimized for screening population (ages 55-80)
- Best performance with LDCT scans
- Not validated for pediatric use
- Performance may vary with different scanner manufacturers

## 📚 Citation

If you use this model, please cite the original paper:

```bibtex
@article{mikhael2023sybil,
  title={Sybil: a validated deep learning model to predict future lung cancer risk from a single low-dose chest computed tomography},
  author={Mikhael, Peter G and Wohlwend, Jeremy and Yala, Adam and others},
  journal={Journal of Clinical Oncology},
  volume={41},
  number={12},
  pages={2191--2200},
  year={2023},
  publisher={American Society of Clinical Oncology}
}
```

## 🙏 Acknowledgments

This Hugging Face implementation is based on the original work by:
- **Original Authors**: Peter G. Mikhael & Jeremy Wohlwend
- **Institutions**: MIT CSAIL & Massachusetts General Hospital
- **Original Repository**: [GitHub](https://github.com/reginabarzilaygroup/Sybil)
- **Paper**: [Journal of Clinical Oncology](https://doi.org/10.1200/JCO.22.01345)

## 📄 License

MIT License - See [LICENSE](LICENSE) file

- Original Model © 2022 Peter Mikhael & Jeremy Wohlwend
- HF Adaptation with Embeddings © 2025 [Aakash Tripathi](https://github.com/Aakash-Tripathi)

## 🔧 Troubleshooting

### Common Issues

1. **Import Error**: Make sure to append model path to sys.path
   ```python
   sys.path.append(model_path)
   ```

2. **Missing Dependencies**: Install all requirements
   ```bash
   pip install torch torchvision pydicom sybil huggingface-hub
   ```

3. **DICOM Loading Error**: Ensure DICOM files are valid CT scans
   ```python
   import pydicom
   dcm = pydicom.dcmread("your_file.dcm")  # Test single file
   ```

4. **Memory Issues**: Model requires ~4GB GPU memory
   ```python
   import torch
   device = 'cuda' if torch.cuda.is_available() else 'cpu'
   ```

## 📬 Support

- **HF Model Issues**: Open issue on this repository
- **Original Model**: [GitHub Issues](https://github.com/reginabarzilaygroup/Sybil/issues)
- **Medical Questions**: Consult healthcare professionals

## 🔍 Additional Resources

- [Original GitHub Repository](https://github.com/reginabarzilaygroup/Sybil)
- [Paper (Open Access)](https://doi.org/10.1200/JCO.22.01345)
- [NLST Dataset Information](https://cdas.cancer.gov/nlst/)
- [Demo Data](https://github.com/reginabarzilaygroup/Sybil/releases)

---

**Note**: This is a research model. Always consult qualified healthcare professionals for medical decisions.