CAD Phantoms

Parametric CAD models for medical imaging phantoms using build123d.

Current Models

• NEMA IEC Body Phantom (nema_wagi.py) - IEC 61675-1 standard body phantom with:
  • Hollow spheres (10-37mm) with filling tubing
  • Lung insert
  • Mounting plate with screws
  • Material assignments via pymat

Setup

Prerequisites

• Python 3.12+
• uv package manager
• VS Code with OCP CAD Viewer extension

Installation

git clone https://github.com/MorePET/cad-phantoms.git
cd cad-phantoms
uv sync

Usage with VS Code + OCP CAD Viewer

1. Select Python Interpreter

1. Open the project in VS Code
2. Press Cmd+Shift+P (Mac) or Ctrl+Shift+P (Windows/Linux)
3. Type "Python: Select Interpreter"
4. Choose the .venv interpreter from this project (e.g., ./.venv/bin/python)

2. Open the OCP Viewer

1. Press Cmd+Shift+P / Ctrl+Shift+P
2. Type "OCP CAD Viewer: Open Viewer"
3. A viewer panel will open (usually on the right side)

3. Run the Model

1. Open nema_wagi.py
2. Run the first cell (#%%) - this imports the libraries
   • VS Code will start a Jupyter kernel
   • Check the terminal for the viewer port (e.g., "Using port 3939")
3. Run subsequent cells to build the geometry
4. Each show() call updates the 3D viewer

Tips

• Run cells individually: Click the "Run Cell" button or use Shift+Enter
• Viewer not updating?: Check the terminal for connection messages
• Clipping planes: Use clip_slider_0/1/2 parameters in show() to cut through the model
• Colors: Set clip_object_colors=True to see material colors in cross-sections

Project Structure

cad-phantoms/
├── nema_wagi.py          # NEMA IEC Body Phantom model
├── pyproject.toml        # Project dependencies
├── uv.lock               # Locked dependencies
└── *.step                # Exported CAD files (optional)

Dependencies

• build123d - Parametric CAD modeling
• ocp-vscode - VS Code viewer integration
• pymat - Material library for CAD applications

License

MIT