Interoperability
DICOMweb 101: Three Services, Four Gaps
DICOMweb is the most approachable thing in medical imaging. Three services, ordinary HTTP, JSON on the wire, and no association negotiation to implement before anything works. An engineer can be productive against QIDO-RS, WADO-RS and STOW-RS in a day, which is exactly why the difficulty gets underestimated. It is not in the three services. It is at the four edges the standard deliberately leaves open, where every implementation invented something different: authorization, bulk export, third-party delivery and capability discovery. This paper is the orientation layer for the engineers and architects who have to build a viewer, migrate an archive or pick a cloud, and it is organised around where the effort actually goes. It sits on top of WP-01, DICOM 101, which covers the standard underneath it. Current to September 2026, and verified against DICOM PS3.18, edition 2026c.
What’s inside
- Why the 1993 protocol cannot be used from a browser, and the twenty-year lineage of the one that can, including the branch that was abandoned
- Path plus suffix: the resource model, the seven suffixes, and the printed defect in the study-level rendering path
- QIDO-RS matching and parameters, and the removal of 204 No Content in the 2026a edition that quietly breaks existing clients
- WADO-RS and the metadata-first pattern every real viewer uses, and why bulk-data substitution has no threshold
- STOW-RS, and how to tell whether a store actually worked when the status code says 202
- The DICOM JSON model: uppercase hex keys, arrays everywhere, and three distinct representations of empty
- Transfer syntax as a media type parameter, HTJ2K and resolution-major ordering, and the two encodings the web forbids
- The four gaps, security in the standard’s own words, the three clouds compared row by row, migrating off DIMSE, and nine expensive mistakes
PDF · 23 pages
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