Status and way forward with Publishing DICOM in XML

Cor LoefChair ad hoc group on Publishing DICOM in XML

Ad hoc WG on DICOM Standard publication and maintenance in XML • Started in WG 10, work item approved

September 2002• Formally moved as ad hoc group to WG

6 in 2003• Decision on way forward to DSC in Dec

2003

Rationale

• DICOM standard big and complex– Difficult to maintain coherence

• Difficult to implement

Objectives

• Create architecture for an XML representation of standard

• Devise procedures for maintenance and publication

Benefits

• Improve consistency of standard• Multiple publication formats

– Word, PDF, HTML, etc.• Improve efficiency of updates• Improve efficiency and consistency of

implementation, test tools, DICOM toolkits

• Establish more powerful method of information modeling

Plan

• Draft framework• Convert Part 6• Convert significant portions of Part 3

and Part 16

“An formal evaluation of the validity of the XML approach will take place the moment part 6, part 16, and a significant part of part 3 are completed in draft, with a plan and concept for the complete DICOM standard. At that moment, and based on the evaluation, the DICOM Standards Committee will take a decision whether or not to continue with the approach. The group is expected to deliver in 2003 the deliverables of the first phase. The goal is then to have part 6, 16 and 3 published in 2004.”

Decision to be taken, as written in workitem:

Directory Structure

Root directory

Individual parts

Folders for documents, stylesheets, schemas, common entity definitions, etc.

Part Directory Structure

main

chapter

appendix

Entity definitions

Other filesImages

main.xml

<!-- entity definitions, including part title -->

<book label="6" id="Part06">

&title-matter;

&chap01;

&chap02;

&chap03;

&chap04;

&chap05;

&chap06;

&chap07;

&chap08;

&appenA;

</book>

Boilerplate text, with part title as parameter

Each chapter is in a separate file

(Better done with XInclude and catalog)

So is each appendix (annex)

DocBook

• Widely used DTD for technical content• Actively developed and maintained by

OASIS• Default stylesheets

– Customizable

• One content multiple renderings– XSL-FO– HTML– …

Output (for each Part)

• FO PDF• Single HTML page• Chunked HTML pages• HTML Help

• Benefit– Cross-references

• Within a part• Across parts

Current Status

• Complete conversion of Part 6• Majority of Parts 3 & 16 converted• To do:

– P3: Tables A.1-1, A.1-2, Annex K (SR encoding example), Annex P (Index)

– P16: some context groups, Annex F (Japanese)– Decide how to represent constraints on IODs,

macros, templates• Complete conversion of Part 12

– For process verification

Deliverables:

• Part 3

• Part 6

• Part 16

• Part 12

Shortcut to part06.lnkShortcut (2) to part06.lnk

Shortcut (3) to part06.lnk

Shortcut (2) to part03.lnkShortcut to part03.lnkShortcut (3) to part03.lnk

Shortcut to part12.lnkShortcut (2) to part12.lnk

Shortcut (3) to part12.lnk

Shortcut to part16.lnkShortcut (2) to part16.lnk

Shortcut (3) to part16.lnk

Plan

• Continue with this effort

• Target: whole DICOM standard in XML as draft available for WG6 review June 2004

• Each part will be assessed on the need to structure the text

Conversion from Word

• Tool: Majix– http://www.tetrasix.com– Converts RTF to sdocbook DTD

(Simplified DocBook)– Works mostly, but needs tweaking

• Prose and “simple” tables converted with this

• Other tools are available, but none can do this perfectly

Conversion of Templates

• Special processing required to recover structure from Word table

• Java program written to do this• Works well

– Caught typos

Figures

• Currently– Majix outputs them from Word as WMF– Use as is, or convert to GIF, JPEG

• Eventually, should be redrawn in SVG– Some can be produced

programmatically– E.g.: Mammo CAD SR IOD template

hierarchy

Math

• DocBook has minimal support for mathematical expressions

• Equations should be rendered as graphics and included inline– Until MathML gets wider support

Tools

• For general XML editing, any text editor can be used– emacs– vi

• XML editors– XML Spy– Morphon (free)– XML Mind (xxe)

XSLT

• Xalan– http://xml.apache.org/xalan

• Saxon– http://saxon.sourceforge.net– Version 7 (& beyond) supports XSLT 2.0

• xsltproc– http://xmlsoft.org/XSLT– In C– Much faster than the others (in Java)

XSL-FO

• Needed to produce PDF• XEP

– http://www.renderx.com• XSL Formatter

– http://www.antennahouse.com• FOP

– http://xml.apache.org/FOP– Free, but less coverage than the others

XML Catalog & XInclude

• XML catalog allows better management of the collection of files

• XInclude allows inclusion of (fragments of) XML files in others– Included files can be validated

What can be done with XML content?• Fewer typos• Consistency checking• Better configuration management• Generation of tables & figures

What Else?

• Process for conversion of all Parts• How to do updates• Develop utilities

– Generate A.1-1 and A.1-2 of P3– Generate template hierarchies– etc.

• Customization of stylesheet

What about new content

• How to incorporate new supplements and CPs?

• Transitional period– No change for authors– NEMA staff will convert FT to DocBook

• Eventually– New process– Do it at granularity level of sections