June 2017 Bjoern.Nolte@siemens.com

Current progress is shown below from the most recent meeting of the DICOM Base Standard (WG-06) and associated official telephone conferences.

WG-06 meets five times a year to do technical review and harmonization of the output from the 31 DICOM Working Groups.

These DICOM supplements add new "chapters" to the standard and the grouped DICOM change proposals, called CPacks or voting packages) contain bug fixes.

Instance Approval

Sup 192 100% (Final Text)

This supplement defines a storage SOP Class to record and convey approval (or disapproval) of DICOM Defined Procedure Protocol instances. The nature, basis and scope of the approval depends on the semantics of the codes used in the assertion. Specific codes and examples are provided for assertions about CT Protocols.

The meeting completed a walk through of the open comments and performed the corresponding edits.

Supplement 192 was voted to go into final text and to be incorporated into the standard.

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Contrast Admin

Sup 164 60% (after Public Comment)

This supplement introduces IODs that describe the administration of imaging agents. The supplement applies to all modalities in which radiographic and ultrasonic imaging agents are introduced into a circulatory system in a controlled fashion (CT, MR, XA, US).

The new SOP Classes describe administration events, flows, pressure, timings, physio-chemical attributes and pharmacological attributes of the agent administration and also consumables related to the administration.

The IOD comes in two variants:

  • The planned variant represents patient specific plans to deliver the imaging agent. The plan is tuned to the characteristics of a patient and needs of that procedure.
  • The performed variant is for reporting the actual administration delivered during a medical imaging study. The actual delivery is captured in this object.

These SOP classes do not describe administration of radiopharmaceuticals, which is addressed by R-RDSR.

A discussion on the semantic meaning of step, phase and plan and what distinguishes them from a logical or physical point of view led to the following advice from Working group 6:

The topic experts shall reflect on the reasons for each grouping on series level. The understanding shall then be used to decide on scoping into plan and step.

Beyond the general discussion, programmed and performed plans were discussed.

Referencing between SR documents was reflected upon. There is a general mechanism to reference its own predecessor. Supplement 164 agreed to use this mechanism to reference between recorded and the planning instance of the document.

A line by line walk-through followed, where the modeling of syringes and how to embed these in the template was one focus point.

The supplement stays in a post public comment state.

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2G RT C-Arm Treatment

Sup 175 60% (after Public Comment)

The scope of this supplement is on C-Arm based treatment delivery. It introduces two new SOP Classes: RT Radiation Set Storage and C-Arm Photon-Electron Radiation Storage.

This supplement is based on the real-world model and specifications defined in supplement 147.

RT IODs are separated into different supplements according to use case: Explicit separate IODs have been developed for specific treatment modalities with the concept of RT Radiation IOD.

For example, Tomotherapeutic, C-Arm, and Robotic beam equipments are modeled separately.

This allows more stringent conditions to be applied to the presence or absence of attributes within those IODs, and thereby increases the potential for interoperability.

Compatibility with First-Generation IODs has been considered as far as possible. Expandability and openness for new treatment modalities and new treatment techniques are important corner stones.

The introduction of the term "change driven" to supplement 175 was not obvious to the meeting participants. Working group 6 proposed to use a clear definition of what this means or to choose another more precise term.

Among other updates to the document, the paragraph on "requirements for RT controlled point sequence attributes that are specified as changes" has been substantially worked on.

A discussion arose on how the difference modalities are separated in the different RT supplements. E.g.

  • Supplement 175 covers C-Arm Photon and C-Arm Electron.
  • Supplement 176 covers Tomotherapeutic, Robotic, Multifixed Source.
  • Not yet covered but planned areas are ion and brachytherapy.

Working group 6 advised to remove the cross-cutting scope concept. The experience is that the available grouping mechanisms have enough expressional power. The pixel spacing macro is a complex illustrating example.

A longer discussion on how to define XYZ coordinates for robot delivery system and references to patient support (table) and the physical room took place. The advice from working group 6 was to be as independent as possible of external references e.g. room objects. This helps avoiding constraints of how future equipment is used or works.

The supplement stays in a post public comment state.

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Multi-Energy CT

Sup 188 60% (after Public Comment)

This supplement defines new types of images generated by Multi-energy (ME) CT scanners.

It introduces a description of ME imaging techniques. While different vendors apply different techniques to achieve ME Images, there is large commonality in the generated diagnostic images.

ME imaging uses multiple parts of the x-ray beam energy spectrum, where source(s) or detectors can be used for differentiation of spectrum.

Important aspects include:

  • Differentiation of materials
  • Better quantification of tissues and organs
  • Generate virtual non-contrast images

The goal is to cover the following image family variants:

  • Material Quantification Image Family: These image types characterize the elemental composition of materials in the image. They provide material quantification using a physical scale.
  • Material Labeling Image Family: These image types classify materials, where each pixel identifies material(s) in that pixel. This can serve as the basis for visualization of different materials, e.g. for coloring of specific material, enhancing or suppressing certain materials.
  • Material Visualization Image Family: These image types allow visualizing material content, usually with colors (color maps, color overlays, blending, etc.)

A special focus on the new module adding and summarizing all specific enhanced attributes filled up parts of the meeting session.

The CT multi energy flag and its type was debated. There was agreement that it cannot be type 1C as this would invalidate current single energy implementations. It was suggested and agreed that it will be defined as type 3.

The supplement stays in a post public comment state.

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WebServices ReDoc

Sup 183 40% (Public Comment)

This supplement re-documents (rewrites) PS3.18 Web Services.

The goals of the rewrite are:

  • Bring the Standard into conformance with the latest Web Standards, especially [RFC7230 - 7234], and [RFC3986 - 3987].
  • Use the Augmented Backus-Naur Form (ABNF) defined in [RFC5234] and [RFC7405] to specify the syntax of request and response messages.
  • Use standard terminology throughout the standard.
  • Use a standard format for documenting services and transactions.
  • Clarify ambiguities and underspecified aspects of the Standard using the CP process.

The most important aspect of the re-documentation is that no semantic content of the Standard should be changed.

Errors, ambiguities, and underspecified aspects of the existing standard have been corrected through the CP process prior to the finalization of this supplement.

A walk-through of the document with inline editing was performed.

A longer clarifying discussion on subscriptions, especially suspend behavior on different levels, took place. Work list and work item levels were considered and the corresponding text was improved.

The work associated with the re-structuring of annexes was presented. What group 6 advised to keep the annex numbering scheme unchanged.

The supplement was approved for public comment.

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Transform AIM/DICOM-SR

Sup 200 40% (Public Comment)

This supplement defines patterns for transformation of measurement and annotation information for use-cases related to the reporting of quantitative imaging results.

The AIM model captures annotation descriptions, graphical drawings, and computational results of image features. The information is captured using user-defined lexicons and/or well-defined medical lexicons such as RadLex, UMLS, SNOMED CT, CPT, ICD-9/10, etc.

Image annotations in AIM (XML based) have been used for cancer lesion measurements and ROIs for capturing quantitative imaging features, and it is desirable to harmonize this effort with similar capabilities that exist in DICOM, to allow AIM and DICOM systems to interoperate for these use cases.

This supplement defines a mapping between compatible components of the AIM model and the DICOM SR TID 1500 Measurement Report applicable to quantitative and categorical description of regions of interest in images. It reuses the existing DICOM SR TID 1500 and the existing family of IODs sufficient to encode it (e.g., the Enhanced SR IOD and Storage SOP Class). Interoperable with current TID 1500 implementations and generic storage systems are important aspects.

Minor changes in the scope and field have been done.

A new added part to DICOM has been proposed, namely part 22.

The transformation guide was reviewed. Improvements were incorporated directly into the text.

The mapping guidance and rules for AIM to SR were scrutinized in detail. Improvements were added on the fly.

A walk-through of the template content and the AIM examples was done. Minor corrections were incorporated directly in the meeting.

The supplement was approved for public comment.

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2G RT Add. Treatment

Sup 176 30% (before Public Comment)

This supplement adds new RT Radiation IODs for non-C-Arm treatment devices. This supplement is based on the real-world model and specifications defined supplements 147 and 175.

It specifically introduces new DICOM objects for:

  • Tomotherapeutic Radiation
  • Multiple Fixed Source
  • Radiation
  • Robotic Radiation

A discussion on the best definition of coordinate systems, frame of reference and robotic detector position helped to create a common and precise understanding.

Working group 6 advised of using a switch mechanism on IOD module definition level to control which content is included in an instance.

The supplement stays in a state before public comments.

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Retire WADO Web Serv.

Sup 198 100% (Final Text)

This supplement retires the WADO-WS Web Service from the Standard. The functionality provided by WADO-WS is now included in and enhanced by DICOMweb. WADO-URI and WADO-RS remain part of the Standard.

Retirement does not imply that these features cannot be used. However, the DICOM Standards Committee will not maintain the documentation of retired features. The reader is referred to earlier editions of the Standard.

The use of the retired features is discouraged for new implementations, in favor of those alternatives remaining in the standard.

The DICOM Standard will not reuse Data Element tags and UIDs that would conflict with retired services.

Supplement 198 was voted to be retired and as final text will be incorporated into the standard.

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Retire Dose from MPPS

Sup 201 80% (Letter Ballot)

RDSR, not MPPS, is used in the IHE Radiation Exposure Monitoring (REM) profile and is the preferred mechanism for submission to registries.

The Radiation Dose Structured Report (RDSR) mechanism has long since replaced MPPS as the mechanism for interchange of radiation dose information for all X-Ray modalities, such as CT, XA/XRF and projection radiography, including mammography.

The optional Radiation Dose Module of the Modality Performed Procedure Step SOP Class was published in 1998, but has not been adopted widely and neither provides a means of persistently storing nor managing the more highly structured radiation dose information that is now commonplace.

The Radiation Dose Structured Report (RDSR) is the preferred mechanism for exchanging radiation dose exposure information (introduced for XA in Sup 94 in 2005 and CT in Sup 127 in 2007), and the continuing presence of the Radiation Dose Module of the Modality Performed Procedure Step SOP Class in the standard is causing confusion (e.g., as is apparent in the recent draft ICRP report on DRLs, "http://www.icrp.org/page.asp?id=256").

DICOM periodically retires various features that have not been used widely in an interoperable manner, or have been superseded by more robust services. Retirement does not require any implementations to stop using them. It does mean DICOM will no longer maintain them.

This supplement retires the Radiation Dose Module from the Modality Performed Procedure Step SOP Class.

Supplement 201 was voted approved for letter ballot.

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CPack 91

WG-06 approved Final Text in June 2017

CPack 92

Current set for September 2017 Final Text.
1629 Add Identical Documents Sequence to the Encapsulated Document Module 1633 Enhance Specification of Range Matching 1635 Add Isocenter Reference System to RDSR 1644 Correct conditions for Selected Segmental Ophthalmic Axial Length Sequence 1652 Update DICOM to reflect changes in IHTSDO SNOMED CT-DICOM Subset for JAN 2017 INT Release 1657 Consolidate Brachytherapy Applicator Geometry Definitions 1658 Dose Reference Beam Dose Verification 1660 Dose Measurement Type in RTSTRUCT 1664 Add Progress Parameters in UPS Progress Module 1675 Add Retain Institution Identity option to Basic Application Level Confidentiality Profile 1676 Remove duplicate anatomy information in irradiation event data in RDSR 1677 Do not include Modifying Device Manufacturer in Confidentiality Profile Attributes 1678 Use of JPEG Family Transfer Syntaxes rather than RLE for YBR_FULL 1679 Add compression pressure to mammography, breast tomosynthesis and projection objects 1680 Add teaching file export related codes 1681 Reference to real world value map used during segmentation 1682 Defined PET Units Defined terms by reference to UCUM used in Context Group 1683 Fix error with QIDO results calculation. 1685 Add session, authentication, authorization audit codes 1686 Add UDI code for use in templates 1687 Allow Segmented Color LUT in Color Palette IOD 1688 Correct Note of Table C.7.6.18-1 Cardiac Synchronization Module Attributes 1689 Correct codes and meanings 1690 Query Key for Anatomic Regions in Study 1691 Add more standard Body Part Examined Defined Terms 1692 Add more statistical multidimensional image component semantics 1693 Add study longitudinal temporal offset from event for clinical trials 1694 Match Segmentation Property Categories with specific Context Group 1695 Add laterality requirement information to anatomical concepts 1696 Clarify condition for Repetition Time (0018,0080) 1697 More structure of rather than entire SNOMED anatomical concepts

CPack 93 candidates

Current candidates for final text in November 2017
Clicking on one specific Change Proposal above will open the actual content.