| DICOM PS3.3 2024d - Information Object Definitions |
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The following Sections specify Modules used for Hanging Protocols.
Table C.23.1-1 specifies the Attributes of the Hanging Protocol Definition Module, which identify and describe the high level definition of a Hanging Protocol, including its overall purpose, and the types of image sets to which it applies. See Annex V “Hanging Protocols (Informative)” in PS3.17 for further explanation.
Table C.23.1-1. Hanging Protocol Definition Module Attributes
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Explanation of the objective or intent of the Hanging Protocol. |
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Identifies the level at which this Hanging Protocol is defined, and the intended use. |
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Sequence that defines the type of imaging Studies to which this Hanging Protocol applies. One or more Items shall be included in this Sequence. See Section C.23.1.1.1. |
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Type of device, process or method that originally acquired the data used to create images or related objects to which this Hanging Protocol applies. See Section C.7.3.1.1.1 for Defined Terms. Required if Anatomic Region Sequence (0008,2218) is not present. May be present otherwise. |
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Sequence that identifies the anatomic region of interest to which this Hanging Protocol applies. One or more Items shall be included in this Sequence. Required if Modality (0008,0060) is not present. May be present otherwise. |
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Laterality of the body part to which this Hanging Protocol applies. Zero length means not applicable. Required if Anatomic Region Sequence (0008,2218) is present. |
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Sequence that identifies a procedure to which this Hanging Protocol applies. |
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Sequence that identifies a reason for procedure to which this Hanging Protocol applies. |
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Identifies the number of prior image sets used in this Hanging Protocol. |
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Sequence describing one or more types of Image Sets to which the Hanging Protocol applies. One or more Items shall be included in this Sequence. See Section C.23.1.1.2. |
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Sequence containing Image Set selection Attributes and values that are used to identify one type of image or object set for the Hanging Protocol. One or more Items shall be included in this Sequence. See Section C.23.1.1.3. |
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Indicates the behavior of matching against an image object when Selector Attribute (0072,0026) is not available in the image object. |
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Data Element Tag of an Attribute from an Image or other IOD to use for Image Set selection. |
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The Value Representation of Selector Attribute (0072,0026). See PS3.5 for Enumerated Values of Value Representation. |
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>>Include Table C.23.4-1 “Hanging Protocol Selector Attribute Context Macro Attributes” |
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>>Include Table C.23.4-2 “Hanging Protocol Selector Attribute Value Macro Attributes” |
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Positive integer identifying which value of a multi-valued Attribute identified by Selector Attribute (0072,0026) is to be used for Image Set selection. The value 1 identifies the first value. The value zero identifies any value. |
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Sequence containing time based Image Set selection categories and values that are used to identify one type of image set for the Hanging Protocol per Sequence Item. One or more Items shall be included in this Sequence. The Image Set Selector Sequence (0072,0022) shall be applied to each Sequence Item to define an image set. See Section C.23.1.1.2. |
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A monotonically increasing integer, starting from 1, incrementing by 1, unique within the Hanging Protocol Instance. |
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Exactly two numeric values, indicating the start and end values of a prior range of Instance acquisition times relative to the date and time of a current image set. The units shall be specified in Relative Time Units (0072,003A). The value pair 0\0 shall indicate a current image set. The value pair n\n shall indicate "prior from the Instance acquisition time of a current image set by n units". Required if the value of Image Set Selector Category (0072,0034) is RELATIVE_TIME. |
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Identifies a prior image set in abstract terms. Exactly two integer values, indicating the range of prior Studies to include. Each value shall be greater than zero, where 1 indicates the most recent prior and higher values indicate successively older priors. The special value -1 shall indicate the oldest prior. NoteRequired if Image Set Selector Category (0072,0034) is ABSTRACT_PRIOR and Abstract Prior Code Sequence (0072,003E) is not present. |
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Identifies a prior image set using coded terminology. Only a single Item shall be included in this Sequence. Required if Image Set Selector Category (0072,0034) is ABSTRACT_PRIOR and Abstract Prior Value (0072,003C) is not present. |
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>>>Include Table 8.8-1 “Code Sequence Macro Attributes” |
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Description of the objective of the image set defined by this Sequence Item. |
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Sequence that provides a coded identifier for the person, group, or site for which this Hanging Protocol was defined. |
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Sequence that identifies the Hanging Protocol from which this Hanging Protocol was derived, or on which it is based. |
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>Include Table 10-11 “SOP Instance Reference Macro Attributes” |
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The Hanging Protocol Definition Sequence (0072,000C) provides a collection of one or more Items that defines the intent for the Hanging Protocol with respect to modality, anatomy, laterality, procedure and/or reason.
This allows for some degree of flexibility in defining the intent for the Hanging Protocol, while providing a precise structure for query matching using the existing rules for Sequence Matching, as defined in PS3.4.
The Hanging Protocol Definition Sequence (0072,000C) does not imply anything about the related image sets. These are defined in the Image Sets Sequence (0072,0020).
When creating a Hanging Protocol Instance, the values that are used for Procedure Code Sequence (0008,1032) or Reason for Requested Procedure Code Sequence (0040,100A) may come from a variety of sources, but are expected to be consistent throughout the domain in which a Hanging Protocol Instance will be exchanged. The following are recommended as potential sources of values.
Procedure Code Sequence (0008,1032):
The Image Sets Sequence (0072,0020) within a Hanging Protocol Instance serves to identify the type of image or other object sets to which the Hanging Protocol is intended to apply. Multiple types of image sets may be identified for a Hanging Protocol, to combine, for example, multiple imaging Studies for a specific anatomy, or multiple imaging Studies performed over a period of time, to monitor the progress of a condition. All image sets shall be for the same patient.
The images to be included in an Image Set may be specified directly by matching Attribute values within the images, or indirectly through Key Object Selection Documents or Presentation States by matching their Attribute values.
Key Object Selection Documents shall be matched by their SOP Class UID. The available Key Object Selection Documents may be further matched on the values of their other Attributes (e.g., Concept Name Code Sequence, Coding Scheme Designator = "DCM" and Code Value = "113003", which has a Code Meaning of "For Surgery"). When the Hanging Protocol Instance is applied, the image object Instances referenced by the matching Key Object Selection Document Instances comprise the image set.
Presentation States shall be matched by their SOP Class UID. The available Presentation States may be further matched on the values of their other Attributes (e.g., Content Label). When the Hanging Protocol Instance is applied, the image object Instances referenced by the matching Presentation State Instances comprise the image set.
Image Sets Sequence (0072,0020) allows other objects such as waveforms and SR documents to be identified. However, Hanging Protocol Display Module operations such as filtering, reformatting, and sorting are defined only for image objects. The only expectation for non-image objects is to associate the objects with a position on a screen.
Each Item in the Image Sets Sequence (0072,0020) shall follow these rules:
Each Item in the Time Based Image Sets Sequence (0072,0030) shall identify one image set, based on time criteria.
The Items of the Image Set Selector Sequence (0072,0022) shall collectively identify one type of image set.
One instance of time based criteria combined with the Items of the Image Set Selector Sequence (0072,0022) shall identify one image set.
The number of image sets identified by an Item of the Image Sets Sequence (0072,0020) shall equal the number of Items in the Time Based Image Sets Sequence (0072,0030).
The value of Image Set Number (0072,0032) in each Time Based Image Sets Sequence (0072,0030) Item shall be unique across all Items of the Image Sets Sequence (0072,0020).
The identification of a current image set is established by the application prior to selection of a Hanging Protocol Instance. The current image set is not necessarily from a single Study.
In mammography screening, for example, the Hanging Protocol defines the current image set plus the screening image set for the patient from the year prior. There would be one Item in the Image Sets Sequence (0072,0020). Within this Item, the Items of the Image Set Selector Sequence (0072,0022) would identify a mammography screening image set type. The Time Based Image Sets Sequence (0072,0030) would have two Items, one to identify the current, and one to identify the prior.
The Image Set Selector Sequence (0072,0022) contains Items that specify the DICOM Attribute Data Element Tags and values that shall be used to identify the image or other object set.
The Image Set Selector Usage Flag (0072,0024) indicates whether the Attribute identified by Selector Attribute (0072,0026) causes matching to succeed or fail if the Attribute is not available in an image object.
Within an Item, Selector Attribute (0072,0026) identifies a DICOM Attribute Data Element Tag that is likely to be present in image or other object Instances that are desired for the Image Set. If it is a multi-valued Attribute, the Selector Value Number (0072,0028) indicates which value is intended to be used for matching. The Selector Attribute VR (0072,0050) identifies the Value Representation of Selector Attribute (0072,0026). The value of Selector Attribute VR (0072,0050) determines which Attribute of the Hanging Protocol Selector Attribute Value Macro is required to specify one or more desired values for the DICOM Attribute. If more than one value is specified for the Attribute, or more than one Item is specified in the Selector Code Sequence Value (0072,0080), then image object Instances with a corresponding Attribute that matches any one of the values shall be included in the Image Set.
The values used for Selector Attribute (0072,0026) are intended to identify a type of image set via the general categories of modality, anatomy, procedure intent and/or reason. Therefore the values of the Attributes represented by Selector Attribute (0072,0026) are likely to be coded terms, Enumerated Values, Defined Terms or free text. The use of free text Attributes is less desirable, because their values are less predictable for matching.
In an image object, some Attributes occur at the top level, or nested within a Sequence or Functional Group Sequence, or both. In addition, a Private Attribute may be identified as a Selector Attribute (0072,0026). The Attributes of the Hanging Protocol Selector Attribute Context Macro identify a Sequence, Functional Group Sequence, or Private Group context for Selector Attribute (0072,0026).
The creator of a Hanging Protocol Instance uses this collection of Attributes to identify one type of image set to which the Hanging Protocol is intended to apply. The user of a Hanging Protocol Instance (e.g., softcopy review workstation or pre-fetching application) uses this collection of Attributes to match a specific image set to a Hanging Protocol, and/or to determine which image sets need to be retrieved in order to use a Hanging Protocol Instance. The Key Attributes to match against to obtain image sets are specified in Selector Attribute (0072,0026) and its context in each Sequence Item.
If the value of the Attribute represented by Selector Attribute (0072,0026) contains a free text description (i.e., Selector Attribute VR = LO, SH, ST, LT, UT), whether exact or partial matching is used to identify a specific Image Instance when applying a Hanging Protocol Instance is implementation dependent.
| DICOM PS3.3 2024d - Information Object Definitions |
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