pydicom is a pure python package for working with DICOM files. It was made for inspecting and modifying DICOM data in an easy "pythonic" way. The modifications can be written again to a new file.
As a pure python package, pydicom can run anywhere python runs without any other requirements, although NumPy is needed if manipulating pixel data.
pydicom is not a DICOM server, and is not primarily about viewing images. It is designed to let you manipulate data elements in DICOM files with python code.
Limitations -- the main limitation of the current version is that compressed pixel data (e.g. JPEG) cannot be altered in an intelligent way as it can for uncompressed pixels. Files can always be read and saved, but compressed pixel data cannot easily be modified.
pydicom documentation is available on Read The Docs.
See Getting Started for installation and basic information, and the User Guide for an overview of how to use the pydicom library. To contribute to pydicom, read our contribution guide. To contribute an example or extension of pydicom that does not belong with the core software, see our contribution repository, contrib-pydicom.