• Why is the "Distance Source to Reference Point" in RDSR accumulated?

    From Stefan Allers@21:1/5 to All on Mon Jun 7 05:52:50 2021
    HI DICOM experts,

    I am wondering why the EV (113737, DCM, "Distance Source to Reference Point") is contained in TID 10004 "Accumulated Projection X-Ray Dose". The distance might depend on the SID and what should be written in case of several acquisitions and the distances
    are not equal?

    As this distance is now requested from IEC 60601-2-54:2009 + A1:2015 + A2:2018 we wonder what value we should take...

    Thanks,
    Stefan

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  • From Stefan Allers@21:1/5 to Stefan Allers on Mon Jun 14 06:31:06 2021
    Stefan Allers schrieb am Montag, 7. Juni 2021 um 14:52:52 UTC+2:
    HI DICOM experts,

    I am wondering why the EV (113737, DCM, "Distance Source to Reference Point") is contained in TID 10004 "Accumulated Projection X-Ray Dose". The distance might depend on the SID and what should be written in case of several acquisitions and the
    distances are not equal?

    As this distance is now requested from IEC 60601-2-54:2009 + A1:2015 + A2:2018 we wonder what value we should take...

    Thanks,
    Stefan

    Hi all,

    any idea who I can contact regarding this issue? According to my understanding the EV (113737, DCM, "Distance Source to Reference Point") should be part of the TID 10003 for Irradiation Events and not an accumulated value? It seems to be placed wrong in
    TID 10004 "Accumulated Projection X-Ray Dose"...

    Thanks,
    Stefan

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  • From Kevin O'Donnell@21:1/5 to All on Mon Jun 14 11:58:41 2021
    Hi Stefan,

    I think you may be looking at an older edition of the standard. While that item was in TID 10004 at one time, there was some refactoring done in 2013 that removed it. You can find the current edition of DICOM at dicomstandard.org/current.

    That item still exists as optional in TID 10007 Accumulated Total Projection Radiography Dose with the Row Description below saying that it's "A single value for Radiography systems calculating reference point dose based on fixed distance". So in the
    case you mention where the distance differs, the attribute would be absent.

    IEC Subcommittee 62B (who authors 60601) usually cross-checks the current DICOM material, but it's not inconceivable that a detail or two fall through the cracks or ends up misaligned.

    In terms of who to contact, I'm glad you asked. :-)
    dicomstandard.org/wgs lists all the DICOM Working Groups. In this case it would be Physics WG-28.
    If you click on the "WG-28 Physics" link on that page, you'll get an overview of the working group scope, activities, and emails for getting in touch.
    If you want to get into deeper dose details, that's where the medical physics experts (which I am not) live.

    Cheers,
    Kevin

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  • From Stefan Allers@21:1/5 to All on Tue Jun 15 14:34:05 2021
    Hi Kevin,

    thanks a lot for the explanations! It is much clearer now. I'll try to get in contact with someone from IEC-6061 for clarification about the outdated requirement for "Distance Source to Reference Point" in TID 10004. For our X-Ray systems we will then
    only write this attribute in TID 10007 if the distance is really fix for all acquisitions.

    Regards,
    Stefan

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