Inquiry About .dcm.head Files in Orthanc with Object Storage

Hi everyone,

We recently enabled storage compression (StorageCompression) in our Orthanc installation using object storage, and we have noticed the appearance of .dcm.head files.

Could anyone please help us with the following points?

  • What are these .dcm.head files?
  • What is their purpose?
  • Is the image data stored separately from these files?

We would appreciate any insights you can provide regarding this behavior.

Best regards,
Rafik

Hi,These files are created by Orthanc to store the dicom tags excluding PixelData. With StorageCompression enabled, orthanc creates the .head files so that it can get quick access to the dicom metadata when responding to queries without the need of decompressing the entire file.
HTH
James

2 Likes

Thanks, that explains a lot. It would be nice if this was in the documentation or in the comments of the option: orthanc: 6679ca3cb466 OrthancServer/Resources/Configuration.json