which group number to use for private tags - DICOM

This is a discussion on which group number to use for private tags - DICOM ; Hi, Which group number should we use when we want to store private tags? I've been using group number: 0x3333 for example, but I've seen group number: 0x0009 used frequently as well. What rules should we follow when picking a ...

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Thread: which group number to use for private tags

  1. which group number to use for private tags

    Hi,

    Which group number should we use when we want to store private tags?
    I've been using group number:

    0x3333

    for example, but I've seen group number:

    0x0009

    used frequently as well. What rules should we follow when picking a
    private tag number for storage?

    Thanks,
    Mark


  2. Re: which group number to use for private tags

    Hi Mark

    For private elements one shall use odd group numbers. Rules are very
    clearly defined in part 5 of DICOM manuals:
    ==================================
    It is possible that multiple implementors may define Private Elements
    with the same (odd) group number. To avoid conflicts, Private Elements
    shall be assigned Private Data Element Tags according to the following
    rules.

    a) Private Creator Data Elements numbered (gggg,0010-00FF) (gggg is
    odd) shall be used to
    reserve a block of Elements with Group Number gggg for use by an
    individual implementor.
    The implementor shall insert an identification code in the first unused
    (unassigned) Element in this series to reserve a block of Private
    Elements. The VR of the private identification code
    shall be LO (Long String) and the VM shall be equal to 1.

    b) Private Creator Data Element (gggg,0010), is a Type 1 Data Element
    that identifies the
    implementor reserving element (gggg,1000-10FF), Private Creator Data
    Element (gggg,0011)
    identifies the implementor reserving elements (gggg,1100-11FF), and so
    on, until Private
    Creator Data Element (gggg,00FF) identifies the implementor reserving
    elements (gggg,FF00- FFFF).

    c) Encoders of Private Data Elements shall be able to dynamically
    assign private data to any
    available (unreserved) block(s) within the Private group, and specify
    this assignment through
    the blocks corresponding Private Creator Data Element(s). Decoders of
    Private Data shall be
    able to accept reserved blocks with a given Private Creator
    identification code at any position
    within the Private group specified by the blocks corresponding Private
    Creator Data Element.

    Note: 1. The versions of this standard prior to V3.0 described shadow
    groups. These
    were groups with a group number one greater than the standard groups.
    Elimination of conflicts in Private Data Element Tags have made this
    distinction obsolete and this terminology has been retired.

    2. The versions of this standard prior to V3.0 specified private group
    element numbers (gggg,10FF-7FFF) reserved for manufacturers and private
    group element numbers (gggg, 8100-FFFF) reserved for users. Elimination
    of conflicts in Private Data Element Tags has made this distinction
    obsolete and this specification has been retired.

    d) Elements with Tags (0001,xxxx), (0003,xxxx), (0005,xxxx), and
    (0007,xxxx) shall not be used. Since each Item within a sequence is a
    self contained Data Set (see Section 7.5 on the nesting of Data Sets
    via Sequences of Items), any Item which contains Private Data Elements
    shall also have Private Creator Data Elements reserving blocks of
    Elements for those Private Data Elements. The scope of the reservation
    is just within the Item. Items do not inherit the Private Data Element
    reservations made by Private Creator Data Elements in the Data Set in
    which the Item is nested.

    Note: 1. If a sequence is itself a Private Data Element and the Items
    within the sequence also have Private Data Elements, then there will be
    Private Creator Data Elements both outside the sequence and within the
    sequence Items.
    2. Different Items may reserve the same block of Private Data Elements
    for different private creators. This is necessary to allow the nesting
    of Data Sets collected from multiple sources into folders.
    ================================================

    I hope this helps.

    Regards
    Bimalendu

    markww wrote:
    > Hi,
    >
    > Which group number should we use when we want to store private tags?
    > I've been using group number:
    >
    > 0x3333
    >
    > for example, but I've seen group number:
    >
    > 0x0009
    >
    > used frequently as well. What rules should we follow when picking a
    > private tag number for storage?
    >
    > Thanks,
    > Mark



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