DICOM News

2^nd gen. RT
Prescription and
segmentation annotation

This supplement defines transfer SOP classes for physician intent and segment annotations for a new generation of radiotherapy (RT) objects.

This supplement lays out the foundation for additional supplements covering all the necessary new RT objects.

These include:

• RT Course
• RT Treatment Phase
• RT Prescription
• Conceptual Volume including RT Dose Histogram, RT Dose Samples, RT Dose Image
• RT Segment Annotation
• RT Radiation Set including RT Radiation with records

Important aspects during the development of the new RT objects included:

• Support for legacy and modern equipment
• Use of new DICOM concepts: Enhanced objects, 3D segmentations, meshes, rigid and deformable registrations
• Separate modelling for specific treatment modalities
• Expandability

The concepts around intent and references to prescriptions came under scrutiny.

The base standard suggested the use SNOMED codes for body anatomy as the preferred coding style.

A discussion examined and clarified the concept of upstream and downstream.

Further progress will be presented in a later base standard meeting before going to final text.

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Contrast
Agent
Administration

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

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

• The Planned Imaging Agent Administration SR Storage SOP Class 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 Imaging Agent Administration SR Storage SOP Class is for reporting the actual administration delivered during a medical imaging study. The operator may program a delivery system with an intended delivery. This object captures the program. The delivery system or a user may deviate from the programmed plan based on a variety of factors. The actual delivery is captured in this object.

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

Focus was put on reviewing codes in the document.

The base standard's advice was to distinguish between parameterized and programmable phases and sequences.

Further progress will be presented in a later base standard meeting before going to final text.

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2^nd gen. RT
C-Arm RT Treatment
Modalities

This supplement covers the RT Radiation Set Storage and C-Arm Photon-Electron radiation storage objects for the new radiotherapy generation objects.

There was no discussion on this supplement as the radiotherapy presentations focus on supplement 147.

Further progress will be presented in a later base standard meeting before going out for letter ballot.

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Web
Services

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

The goals of this re-documentation are:

• Factor out text that is common to multiple services and in doing so 1) ensure uniformity and 2) make that commonality more clear and concise for readers.
• Use a uniform format and style for documenting DICOM web services, making it easier to navigate and more efficient for readers implementing multiple services
• Bring the Standard into conformance with current 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 consistent terminology throughout the Standard.
• Use a consistent format for documenting services and transactions.

The most important aspect of the re-documentation is that no technical requirements of PS3.18 have been changed. Errors, ambiguities, and underspecified aspects of the current PS3.18 have been corrected through the CP process prior to the finalization of this supplement.

Focus was put on reviewing chapter 10.

Further progress will be presented in a later base standard meeting before going out for letter ballot.

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Multi Energy
CT

This Supplement extends the CT Image IOD and Enhanced CT Image IOD to support new types of images generated by Multi-energy (ME) CT scanners.

It describes various ME imaging techniques. While different vendors apply different techniques to achieve Multi-energy images, there is large commonality in the generated diagnostic images. It adapts existing attributes of the CT / Enhanced CT IOD to fit ME techniques.

Multi-energy CT acquires pixel information, which correlates to different X-Ray spectra to enable differentiation, quantification and classification of different types of tissues.

To detect the different X-Ray spectra, Multi-energy (ME) CT imaging uses combinations of different Source(s) and Detector(s) technologies such as current switching X-Ray tubes, spectral detectors, multi-layer detectors, multi-source and detector pairs.

Multi-energy CT data can be reconstructed and processed in different ways to serve a variety of purposes.

• Differentiate materials that look similar on conventional CT images, e.g., to differentiate Iodine and Calcium in vascular structures or to differentiate vascular structures from adjacent bone.
• Quantify base materials to accurately define tissues and organs. The intent is to quantify materials, and to extract regions and organs based on their composition.
• Generate virtual non-contrast images from a contrast-enhanced image rather than having to scan the patient twice.
• Reduce beam hardening artifacts.
• Enhance the effect of contrast such as highlighting Iodine and soft tissue.

The changes related to incorporating real world value mapping were presented.

The aspects around constant or switching regarding X-ray sources and tubes were examined. Especially how to model timing of switching on and off during passes and acquisitions.

Further progress will be presented in a later base standard meeting before going out for letter ballot.

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Security: CRYPTREC
TLS profiles

This supplement adds a new Secure Connection profile to make DICOM consistent with the latest recommendations from the Japanese CRYPTREC committee.

The CRYPTREC TLS Profile requires compliance with the IETF BCP 195 Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) plus support for the additional cypher suites specified by the CRYPTREC committee. This profile requires that TLS negotiation start with the strong security protection parameters, and allows progressive negotiation of weaker protection down to a specified minimum protection limit.

The CYPTREC committee has extended the BCP195 recommendation by adding cypher-suites that must be available for negotiation, and therefore a new profile beyond those in Supplement 204 is needed.

The supplement was voted to go out for public comments.

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Conformity
Assessment

This supplement extends the standard with Conformity Assessment aspects, including an extension of the requirements, and new sections on test scenarios, test cases, and product conformity assessment reporting.

This together forms a test framework that, when used, will guarantee that a well verified product - conforming to its DICOM Conformance Statement - will be released, with proper evidence of the associated validation activities.

A comprehensive overview has been created by analysing all statements with "conform" and "claim" within the DICOM standard.

These statements, roughly 500, have been categorized in majors and minors. A high level discussion and walkthrough of categories took place.

Web services and realtime video have not yet been covered.

Further progress will be presented in a later base standard meeting before going out for public comments.

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Improvements in
Conformance Statement

This supplement focuses on rewriting part two, DICOM conformance, of the standard.

The goal is to achieve better interoperability and machine processing of DICOM conformance statements.

The question of including a conformance template within part two or to generate it, out of the standard, came up.

It was considered advantageous if the template is a separate generated MS Word template.

It was discussed if the template should be populated minimal or maximal.

Further progress will be presented in a later base standard meeting before going out for public comments.

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Paradigm Protocol
Storage

This supplement adds paradigm protocol storage to DICOM.

Paradigms are used to trigger stimuli used during functional scanning to capture the patient's brain activities.

The flow of events are:

• A paradigm definition is created
• A stimuli training run is performed with the patient and the responses are recorded.
• An acquisition is executed with the paradigm stimuli. Responses and acquired images are recorded and stored.
• Suitable post processing is performed.

It is a working assumption that there is a paradigm creation app and specialized post processing involved.

Further progress will be presented in a later base standard meeting before going out for public comments.

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