March 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 DICOM change proposals (grouped into "CPack" voting packages) are bug fixes.

RT C-Arm treatment

Sup 175 20% (In Work)

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 beams 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 supplement stays before the public comment phase and will be revisited in the next Base Standard meeting.

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RT C-Arm Radiation

Sup 176 20% (In Work)

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 Tomotherapeutic Radiation-, Multiple Fixed Source Radiation- and Robotic Radiation DICOM objects.

The supplement was presented the last time to the working group 6 about two years ago.

A walkthrough of the modules in part 3 was completed.

The content has been made more concise by reusing attributes from other parts of the second generation RT supplements.

The description and requirements for RT control points were thoroughly discussed and formulated.

A longer discussion on how to optimally encode image pixels was held for the object variants: Image, Histogram and Samples. The RT community are considering the enhanced approach as with MR enhanced images. The requirements for RT Dose objects is to store different pixel data blobs around several tumors with the complication that the resolution may differ between tumor locations.

The supplement stays before the public comment phase and will be revisited in the next Base Standard meeting.

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Redoc. Part 18

Sup 183 20% (In Work)

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

The goals of this 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.

The transaction handling, especially the handling of cancel scheduled work item was dwelled upon in detail. The discussion prompted the proposal to rewrite the cancel text all together.

The behavior when asking for a group of updates and a partial failure occurs was scrutinized. The concluding idea is to change and update as much as possible and to report back which parts of the update did not succeed. The decision point is around optimizing for simple transactions or for behavior and state changes.

The supplement stays before the public comment phase and will be revisited in the next Base Standard meeting.

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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. Multi-energy (ME) CT imaging involves techniques, including scanning, reconstruction, and processing, and the use of multiple parts of the x-ray beam energy spectrum, whether source(s) generate different parts of the spectrum or the spectra are differentiated by the detector(s).

The key use cases are:

  • Allowing better differentiation of materials that look similar on conventional CT images.
  • Generate virtual non-contrast images from a contrast-enhanced avoiding scanning the patient twice.
  • Allowing to reduce beam hardening artifacts.
  • Enhancing the effect of contrast such as Iodine and soft tissue

The overview slides were presented.

A question from the public comment phase was discussed in detail. If there are several energy levels, which value shall be put in the KVP attribute? One idea being discussed was to leave it empty and have other attributes coding useful real values.

A proposal was made to add a second new conditional attribute, in the case that the KVP value is synthetic. This approach would not break older applications.

The general issue of how to populate classic CT attributes was dwelled upon. The filling of these attributes for new multi energy objects is problematic when there are no suitable values.

The advice from working group 6 was to leave the values blank if there are no multi energy equivalents.

The supplement continues to be reviewed. The next milestone is Letter Ballot.

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Parametric Blending

Sup 189 100% (Final Text)

This IOD describes how to blend color sources such as parametric maps together with other images with a consistent color presentation.

Parametric Maps can be used to store the quantification of a specific measurement. The Advanced Blending Presentation State defines the blending of the content of different Parametric Maps with an optional anatomical image as underlay, showing the measurements (e.g., BOLD fMRI, Diffusion maps, CT/MRI Perfusion maps, FDG PET map) in relation to the anatomical structure. Blending can be performed on any combination of Images.

The Supplement defines information that is needed to combine the different maps and show the combination. This way the user will be able to relate different items together, giving the opportunity to get a full overview instead of seeing every single item in isolation.

Displayed Area and Graphic modules are included to allow the user to add graphical information, for example, marking the Motor Cortex on the combined image.

The usage is described by using an example of an fMRI study in a new chapter in PS3.17 as Informative Annex.

The more appropriate name of the supplement was proposed as Parametric Color Blending.

An excursion around the main use case, to overlay an anatomical image with one or more color maps, led to an update of the scope and field section of the supplement. More complicated scenarios were discussed too: To blend a multi energy CT image with and without contrast together with several color maps.

The supplement was voted to become part of the standard as final text.

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Patient RDSR

Sup 191 100% (Final Text)

This Supplement is creating a structured report to contain the information concerning the recording of the estimated radiation dose to a patient.

This includes radiation dose from CT, projection X-Ray, and radiopharmaceutical administration (diagnostic and therapeutic). Occupational radiation exposures and dose from external beam therapy, ion beam therapy, or brachytherapy is out of scope.

For the Patient Radiation Dose Structured Report (P-RDSR) a new Structured Report (SR) object template and SOP Class is defined. This SR object, independent of the images or the MPPS, is routed to an appropriate Radiation Dose Information Reporter System.

This SR dose object allows the data flow and data management of patient estimated radiation dose reports to be disentangled from the data flow and data management of images.

It is expected that dose application vendors are the main creator of the reports described in this supplement.

It was suggested to consolidate regarding abbreviations in the supplement.

Enhanced, Comprehensive 3D and Extensible SR were added to the Comprehensive SR objects with possible relations to Patient Dose SR reports.

A deep dive into scenarios for measurements showed different approaches. The discussion circled around the best way to model and code the result. For example when there are several measurements in a vessel, it is possible to model and code the mean, the max or the min value from all measurements.

Working group 6 advised against having a hint property for codes when the consumer of the report has to understand the model anyway.

The supplement was voted to become part of the standard as final text.

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Ophthalmic Tomo. Angio

Sup 197 100% (Final Text)

This Supplement defines Storage SOP Classes to support en face images acquired using ophthalmic optical coherence computed tomography (OCT) technology.

En Face angiography images are derived from images obtained using OCT technology (i.e., structural OCT volume images plus angiographic flow volume information).

With special image acquisition sequences and post hoc image processing algorithms, OCT angiography detects the motion of the blood cells in the vessels to produce images of blood flow in the retina and choroid with capillary-level resolution.

The resultant en face angiography images are similar to images obtained in retinal angiography with contrast dye administered intravenously, though clear differences are observed when comparing these two modalities.

OCT angiography technology enables a high resolution visualization of the retinal and choroidal vascular network to detect the growth of abnormal blood vessels, and to provide additional insights in diagnosing and managing a variety of retinal diseases including diabetic retinopathy, neovascular age-related macular degeneration, retinal vein occlusion, and others.

This supplement:

  • Updates the Ophthalmic Tomography IOD to identify that the SOP Instance is suitable for volumetric analysis, by requiring attributes related to defining spatial relationship (e.g., Pixel Measures, Plane Orientation, Plane Positions, etc.)
  • Adds a CID to identify the Retinal Segmentation Surfaces used when generating a Surface Segmentation SOP Instance (e.g., capturing OPT surface mesh information).
  • Adds a SOP Class to encode the OCT B-scan volume analysis information (such as angiographic flow volume information)
  • Adds a SOP Class to encode derived en face image(s). En face images may be based on structural OCT volumes and surface mesh only or structural OCT volumes, surface mesh plus angiographic flow volume information.

A longer discussion around the use, abbreviations and naming of the OCT, OPT, OCT-A and En Face terms took place.

The conclusion was to use full names and to avoid abbreviations as much as possible.

The supplement was voted to become part of the standard as final text.

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Retire WADO Web Serv.

Sup 198 80% (Letter Ballot)

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.

It was clarified how to guide the user and reader of DICOM in the case of a retired DICOM feature. The idea is that the latest DICOM release besides expressing the retirement of a feature also to include a reference to the last release, which contain the retired content before the retirement.

This retirement supplement was approved to have reached Letter Ballot maturity.

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Transform AIM/DICOM-SR

Sup 200 10% (First Read)

The Annotation and Image Markup (AIM) project defines a UML model and an XML schema for describing the observations that humans or machines make about specific semantic types of information in images: anatomic entities, imaging observations and their characteristics, quantitative imaging features of targets of interest, and other information about targets in images. AIM enables recording qualitative and quantitative features of images.

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

Image annotations in AIM 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.

The overview slides were presented as an introduction to the scope and goal with the supplement.

The AIM structure and use of an XML format is easier to get into and needs less expert know how than the DICOM SR approach. One important strength of the DICOM SR model is stringent use of coded terms and dictionaries for definitions, for example user-defined lexicons and well-defined medical lexicons such as RadLex, UMLS, SNOMED CT, CPT, ICD-9/10.

The same markup objects are available in both AIM and DICOM SR, e.g. ROI, Segmentation and Contour.

The specific task of the supplement is to map from the AIM model to the DICOM SR TID 1500.

A comprehensive guidance to the supplement is available in the chapter "guide".

The supplement stays in work before the public comment phase.

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Retire Rad.Dose in MPPS

Sup 201 40% (Public Comment)

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

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.

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").

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) 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.

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

A walkthrough of the retirement proposal was done.

The retirement proposal was voted ready to be distributed for public comments.

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Real-Time Video

Sup 202 10% (First Read)

This Supplement describes the DICOM transport protocol for real-time video and associated medical data.

DICOM has developed several standards for the storage of medical video in for example endoscopy, microscopy and echography. This supplement adds support for real-time video in the operating room. Additionally to the real time video stream this supplement also covers the necessary associated information like patient demographics, study description or 3D localization of imaging sources.

The proposal defines an IP-based new DICOM standard for the transport of real-time video including quality compatible with the communication inside the operating room.

SMPTE ST-2110, elaborated on the basis of Technical Recommendation TR03 originated by the VSF (Video Services Forum) is used as a platform for the DICOM standard.

The specific level of requirements (size and complexity of metadata, quality of image, ultra low latency, variety of image resolution, restriction to pixel ratio introduce some necessary restrictions of the SMPTE ST-2110 recommendations.

The main use cases were presented, for example overhead cam, monitoring, fluoroscope and ECG.

The main proposed idea was to separate the video from meta-data into two separate streams.

A longer elaboration around the use of DICOM Real Time Video including layout controller applications and medical video recorder took place.

The supplement stays in work before the public comment phase.

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CPack 90

WG-06 approved Final Text in March 2017

1323 Clarify Audit Code Meanings 1513 Clarification of meaning of entrance dose 1590 Add more PET Radiotracers 1604 Fix Type of Dimension Organization UID (within the Dimension Index Sequence) 1615 Add Note to TID1210/1211 Equivalent Concept 1625 Define Conformance for an All-SOP-Class Storage Server 1627 Add tracking ID to Presentation State 1628 Note on limitations of Presentation States 1630 Clarify Changes in Control Point Meterset Values 1631 Clarify Definitions for Types of Context Group References 1638 Unify encoding of code values in DICOM audit message 1642 Change multiplicity for Ophthalmic Axial Length Measurements Segmental Length Sequence 1643 Change type of Signal Noise Ratio for Ophthalmic Axial Measurements Related Information Macro 1645 Add Unassigned Shared and Per-Frame Converted Attributes functional groups to Parametric Map 1646 Add repeat flag and reason to RDSR to help with outlier analysis 1647 Correct SNOMED lesion codes and synonyms 1648 Correct requirement for conversion source in legacy converted images and tractography results 1649 Clarify use of Other Patient IDs Sequence with Issuer and related Attributes as Query keys 1651 Update DICOM to reflect changes in IHTSDO SNOMED CT-DICOM Subset for JUL 2016 INT Release 1654 Clarify that RLE encoding covers all bits allocated 1656 Add Content Date and Time to RT Dose Module 1659 Add Dose Reference UID To Fraction Scheme 1661 Correct Code in CID 9250 1662 Define the encoding order for OPT Attribute Reference Coordinates (0022,0032) 1665 Add MR Diffusion Model Quantities and Parameters for Parametric Maps and ROI Measurements 1666 Add Observation DateTime to Acquisition Context

CPack 91

Current set for June 2017 Final Text.

CPack 92 candidates

Current candidates for final text in September 2017
1633 Enhance Specification of Range Matching 1635 Add Isocenter Reference System to RDSR 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

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