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dicom

what's the purpose of wado-rs vs Dicom Service Class Users/Providers

I am trying to figure out what's the difference between transferring dicom files with a (SCU/SCP) like pynetdicom3 vs using the wado api.

Both methods can be used for transferring dicom files. But I can't figure out what's the standard use case for each?

Solution

  • First of all, you can implement all common use cases with both approaches. The difference is rather in technology you are using and systems you want to interface with than in features supported by the one or the other approach.

    The "traditional" TCP/IP based DICOM services have been developed since 1998. They are widely spread and widely supported by virtually all current systems in the field. From the nowadays perspective they may appear a bit clumsy and they have some built-in glitches (e.g. limitation to 127 presentation contexts). Still they are much more common than the web-based stuff.

    Especially when it comes to communication use cases across different sites, it is hard to implement them with the TCP/IP based protocols.

    The WADO services have been developed by the DICOM committee to adopt new technology and facilitate DICOM implementation for application based on web technology. They are quite new (in terms of the DICOM Standard ;-) ). Having said that the major use case are web-based applications, I have not seen any traditional modalities supporting them yet, and I do not expect them to come up in the near future. This is because, you can rely on PACS supporting TCP/IP based DICOM but you would have to hope for WADO. There is a tendency for PACS systems to support WADO in addition to TCP/IP to facilitate integration of web viewers and mobile devices where an increasing number of applications only supports WADO.

    So my very subjective advice would be:

    • For an application that is designed for the usage within a hospital: Stick with TCP/IP based DICOM, since you can be quite sure that it will be supported by the systems you are going to interface with.
    • If connectivity via internet is a major use case, or your application uses a lot of web technology, consider using WADO but investigate the support for WADO among the relevant systems you need to interface with. This probably depends on the domain your application is targeting.