Tools for Computational Pathology

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An open-source toolkit for computational pathology and machine learning.

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Tutorials, example vignettes, technical notes, and a complete API reference can be found at


There are several ways to install PathML:

  1. pip install from PyPI (recommended for users)
  2. Clone repo to local machine and install from source (recommended for developers/contributors)
  3. Use the PathML Docker container

Options (1) and (2) require that you first install all external dependencies:

We recommend using conda for environment management. Download Miniconda here

Note: these instructions are for Linux. Commands may be different for other platforms.

Installation option 1: pip install

Create conda environment:

conda create --name pathml python=3.8
conda activate pathml

Install external dependencies (Linux) with Apt:

sudo apt-get install openslide-tools g++ gcc libblas-dev liblapack-dev

Install external dependencies (MacOS) with Brew:

brew install openslide

Install OpenJDK 8:

conda install openjdk==8.0.152

Install PathML from PyPI:

pip install pathml

Installation option 2: clone repo and install from source

Clone repo:

git clone
cd pathml

Create conda environment:

conda env create -f environment.yml
conda activate pathml

Install PathML from source:

pip install -e .

Installation option 3: Docker

First, download or build the PathML Docker container:

Then connect to the container:

docker run -it -p 8888:8888 pathml/pathml

The above command runs the container, which is configured to spin up a jupyter lab session and expose it on port 8888. The terminal should display a URL to the jupyter lab session starting with<.....>. Navigate to that page and you should connect to the jupyter lab session running on the container with the pathml environment fully configured. If a password is requested, copy the string of characters following the token= in the url.

Note that the docker container requires extra configurations to use with GPU.
Note that these instructions assume that there are no other processes using port 8888.

Please refer to the Docker run documentation for further instructions on accessing the container, e.g. for mounting volumes to access files on a local machine from within the container.

For more information, please refer to the installation instructions on the PathML GitHub repository


CUDA must be installed to use GPU acceleration for model training or other tasks. For the most up-to-date instructions, refer to the official PyTorch installation instructions.

Check the version of CUDA:


Install correct version of cudatoolkit:

# update this command with your CUDA version number
conda install cudatoolkit=11.0

After installing PyTorch, optionally verify successful PyTorch installation with CUDA support:

python -c "import torch; print(torch.cuda.is_available())"


If you use PathML in your work, please cite our paper:

Rosenthal J, Carelli R, Omar M, Brundage D, Halbert E, Nyman J, Hari SN, Van Allen EM, Marchionni L, Umeton R, Loda M. Building tools for machine learning and artificial intelligence in cancer research: best practices and a case study with the PathML toolkit for computational pathology. Molecular Cancer Research, 2021. DOI: 10.1158/1541-7786.MCR-21-0665


The GNU GPL v2 version of PathML is made available via Open Source licensing. The user is free to use, modify, and distribute under the terms of the GNU General Public License version 2.

Commercial license options are also available.


Questions? Comments? Suggestions? Get in touch!