Chairman: David Murray Ph.D.
TomoTherapy Incorporated
dmurray@tomotherapy.com
Vice Chairman: Bruce Curran, ME, MS
University of Michigan Medical Center
bcurran@umich.edu
Secretariat: National Electrical Manufacturers Assoc.
1300 North 17th Street, Suite 1847
Rosslyn, VA 22209 http://medical.nema.org
Secretary: Stephen Vastagh, NEMA
ste_vastagh@nema.org
Working Group 07
(Radiation Therapy
Objects)
DICOM
Digital Imaging and
Communications in Medicine
MINUTES
MEETING:
DICOM WORKING GROUP 7 – RT OBJECTS
DATE AND TIME:
January 23-25, 2006
PLACE:
AAPM Headquarters
College Park, MD
MEMBER ORGANIZATIONS REPRESENTED
AAPM, U. of MI +
BrainLab
BrainLab
Computerized Medical Systems
Elekta
Elekta
ITC-ATC / Washington Univ. St. Louis
Nucletron
Philips Medical Systems +
Siemens Medical Solutions
Siemens Medical Solutions
Tomotherapy
Tomotherapy
Varian Medical Systems
Bruce Curran
Christof Schadt
Marc Goepfert
Bill Bennett
Mike Ullrich
Colin Winfield
Walter Bosch
Jaap Pijpelink
Scott Johnson
Derek Lane *
Johannes Stahl
Dave Murray
Bob Philbin
Uli Busch
* Jan. 25 only
+ Jan 24 - Attended WG-06 meeting on behalf of WG-07
MEMBER ORGANIZATIONS NOT REPRESENTED
ATC/ Univ. of Florida
Calypso Medical
IMPAC Medical Systems
Institute for Clinical Biochemistry
NAS/Nomos Division
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Optivus Technology
Prowess
RaySearch Laboratories
Riverain Medical
Shands Cancer Center
UT/MD Anderson
OBSERVERS PRESENT
None
OTHERS PRESENT
NEMA Staff
Stephen Vastagh
Presiding officer:
Secretary:
Dave Murray, Chairman
Stephen Vastagh
1.
OPENING, APPROVAL OF AGENDA, INTRODUCTIONS
The Chair welcomed members; self-introductions followed. The Agenda was approved.
2.
ANTITRUST GUIDELINES TO BE OBSERVED
The NEMA antitrust meeting rules were reviewed.
3.
MINUTES
The minutes of the October 2005 (ASTRO) meeting were approved.
4. DICOM STANDARDS COMMITTEE REPORT
No comments
5. STRATEGY DOCUMENT
No comments received
6. CHANGE PROPOSALS
WG7 discussed the process of editing and submitting CPs, and decided to appoint a WG7
CP Editor, Bruce Curran. Mike Ulrich (Elekta) also volunteered to participate in this process.
The group noted that all new CPs should be prepared according to the CP template,
available at http://medical.nema.org/handbook.html, “CP Template” link.
The following CPs were reviewed at WG7 then at the concurrent WG6 meeting:
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
CP554_vp.doc (Isocenter Position for RT Images): Wording changed to indicate that
Patient Position is for indicative purposes only, to allow implementations to check
general orientation of patient. Some typos corrected. Presented to WG6 on Tuesday.
Accepted for publication by WG6.

CP576_04.doc (Motion Synchronization): WG7 considers that all currently defined
terms are applicable or potentially applicable to RT. An explanation of why the new
attributes are required has been added to the rationale. After some discussion, the
gating information has been moved to the Patient Setup Module. Presented to WG6
on 1/24/06. Accepted by WG6 for inclusion in Voting Packet 35.

CP577_lb.doc (Clarification for Delivered Meterset): Bruce converted drawings to
Word. Accepted for publication by WG6.

CP614_02.doc (Beam Depth): Added attribute text clarifying radiological depth, and
fixed some formatting and typos. Accepted by WG6 for inclusion in Voting Packet
35.

CP615_03.doc (Treatment Delivery Type): Beam Energy and Beam Energy Unit etc
modifications have been removed, since WG7 considers there is no consensus on
KVCT beam acquisition and should be the subject of a separate CP. This CP now
addresses just the need to specify that a beam is a SETUP beam. Accepted by
WG6 for inclusion in Voting Packet 35.

CP616_03.doc (Gantry Pitch Angle in RT): Minor corrections, including title change,
attribute renumbering. Clarification of type 3 condition. Parent sequences included.
Accepted by WG6 for inclusion in Voting Packet 35. Bruce converted drawing to
Word.

CP617_03.doc (Patient Positioner, Pitch & Roll): Removed requirements for Type 3
attributes. Fixed typos. Parent sequences included Accepted by WG6 for inclusion
in Voting Packet 35. Bruce converted drawing to Word.

CP618_03.doc (RT Stopping Power Ratios): Deleted text as a strikeout. Accepted
by WG6 for inclusion in Voting Packet 35.
7. SUPPLEMENT 102
Regarding the remaining Supplement 102 issue, Uli made the following changes:
1. C.8.8.y.5.4.1 Gantry Beam Line: Removed reference to PITCHED TABLETOP
system, because this does not exist any more (the TABLETOP system has a pitch
angle now).
2. In Primary Dosimeter Unit (300A,00B3) in RT Ion Beams and RT Ion Beams Session
Record, removed MAMPSEC as a unit. This is in line with WG6 comments received
for CP 615 .It means, that we cannot specify the meterset for KV in MAMPSEC. WG
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7 considers this is only an issue as soon as one wants to calculate dose for KV,
which is hardly important enough now to make a different contruct in the Ion
Supplement. If we need this, than we can add later a construct in BOTH modalities,
which is compliant with Photon (and therefore will be compliant with Proton as well).
3. The "Corrected Value" attribute listed in the Part 6 Addendum was changed to
"Correction Value", to be consistent with its naming elsewhere in the IOD and in
CP553.
Supplement 102 was discussed with WG6, and the changes suggested by Scot and Uli in
their emails were implemented and discussed with WG6. The resulting version is V17,
located in the meeting folder. WG6 approved Supplement for publication. Uli will
convert the drawings prior to inclusion in the new DICOM draft.
Note: To convert a Visio drawing for use in a DICOM Supplement or CP: Save the Visio
drawing as a Windows Meta-File (WMF) document. Then insert a new drawing in the word
document, and ‘insert picture from file’ when inside the frame. Then right click on the
picture, select “Edit Picture”, and select “Convert to MS-Draw”.
8. SUPPLEMENT 74
Discussion with WG6:

Need to change NEMA Suite 1847 to Suite 1742. Done in V8

OIS term in actors should be renamed “Department System Scheduler” (DSS). Done
in V8

Use use case actor terms “Performing SCU”, “Scheduling SCU” (not used in RT), and
“SCP” in use case actor descriptions. Done in V8.

State that the mapping between SPSs and PPSs is 1-1 in RT applications, i.e. all
PPSs are scheduled and completed in one step. Added in Section Z.1 in V8.

In Part 2, use “Transfer” instead of “Workflow Management” in “Category”. Done in
V8.

Consider use of a simple normalized SOP class (with an RT Beams Delivery
Information Module and a SOP Common module). Discussed on 1/25, when, it was
considered convenient to use a C-MOVE model for moving the IOD (since this
approach is used for the other input objects), in which case a Patient/Study/Series
hierarchy is required). Also, GP Worklist does not seem to support retrieval of
normalized IODs (Study UID etc are required attributes, see Part 4 K.6-2). No action
required.

Set Modality to a value of “WK” (for WORK), or consider creating a series-level
module that does not contain a “Modality” attribute, or encode Modality as a empty
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value (since it will not be used to display a list to the user, for example. In V8,
Encoded Modality item of WK - simplest approach (does not require
redefinition of RT Series) and allows systems to display the IOD (even though
no system should display these objects to a user under normal
circumstances).

The presence of many type 3 attributes in the RT Beams Delivery Information Module
(specifically, the setup verification parameters) was discussed. It was felt that as a
minimum, these attributes would better be kept in a separate module. This module
was reworked on 1/25 in V8, and more structure was introduced into the
module and the number of optional attributes reduced.

Decide if Setup Instructions could be constrained to various types, with attributes
conditional on this type. List developed by Johannes and discussed and
extended on 1.25. New list is in V8.

WG6 considered that it might be useful to define a new “Simple Worklist”, where the
1-1 mapping between SPS and PPS means that SPS and PPS can be combined into
a single entity. WG6 stated that they would consider such a thing, and if they decided
to go ahead and it was ready in time for Supplement 74, GP Worklist could easily be
replaced by “Simple Worklist” at a later date. Modified the Supplement 74 title to
“Use of Worklist in RT” (V8) to not exclude use of such a service.

Remove code values in CID-9231 extension. Done in V8.

In interaction diagrams, add an ‘arrow to self’ saying ‘extract list of object UIDs from
SPS’. Done in V8.

In interaction diagrams, change arrow 6 to ‘Set’ (not ‘update’) GP-SPS (IN
PROGRESS). Done in V8.

In interaction diagrams, change arrow 8 and corresponding definition to “Start
Treatment Session”, and arrow 14 and corresponding definition to “Treatment
Session Completed”, to allow for the fact that >1 SPSs could be used to achieve a
session (as indicated in the text below the diagram). Could also add a note on the
interaction diagram or in the text. Diagrams have been updated (V8) and a note
added to Step 8 description.
A RT Worklist subgroup will be formed to work on Supplement 74 via T-cons. Individuals
identified for membership of this group are: David Murray (TomoTherapy), Johannes Stahl
(Siemens), Jaap Pijpelink (Nucletron), Colin Winfield (Elekta), Ulrich Busch (Varian), Stuart
Swerdloff (IMPAC Elekta), Bob Philbin (TomoTherapy), with observers Bill Bennett (CMS),
Scott Johnson (Philips). Christof Schadt (BrainLab), Marc Gopfert (BrainLab), Mike Ulrich
(Elekta), Bruce Curran (UMich).
10. NEW CHANGE PROPOSALS
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
RT_CPLeafJawPositions_03.doc: Leaf/Jaw Positions: Christof introduced this CP,
intended to correct issues with the leaf subscripting in the Leaf/Jaw Positions
attribute (300A,011C) of the RT Beams Treatment Session Record Module. WG7
discussed this issue and considers that it is a typo, since the order described is not
the IEC leaf subscript order as stated, and the other two occurrences of this attribute
in the standard do not contain this error. Jaap checked and confirmed that Nucletron
products have not implemented according to this type. Dave will email David Clunie
asking whether this change is to be treated as an editorial change or a CP.

RT_CPRefBeamSeqType_01.doc: This CP addresses a typo in the Referenced
Beam Number attribute description in C.8.8.14, which references Referenced Beam
Sequence as (300A,0004) instead of (300C,0004). This also occurs in C.8.8.14.1.
Dave will email David Clunie asking whether this change is to be treated as an
editorial change or a CP.

RT_CPCompensatorRowCols_01.doc: This CP clarifies the direction of the rows
and columns in a IEC Beam Limiting Device Coordinate System. Ready for
presentation to WG6.

General Accessories: Johannes discussed that imaging panels and potentially
other devices that are in the beam path should be modeled as an accessory with a
code, since the effect of these devices need to be modeled dosimetrically. Johannes
suggested that a new sequence (like the wedge and compensator sequences)
should be added, called “Generic Accessory Sequence”. Such a sequence would
contain an ID, an index, and a name, and potentially an attribute with defined terms
such as IMAGER etc. WG7 considered that this is a worthwhile enhancement, and
suggested to Johannes that he go ahead and develop a CP. Johannes presented the
initial CP later in the morning. It will be discussed again in the next WG7 meeting.

AE Diagrams in RT: Bill Bennett discussed the fact that AE Diagrams in RT could be
modified and extended to more accurately represent the relations between DICOM
objects in RT. He presented an example diagram for RT Structure Set as an
illustration, and also a more detailed diagram showing key attributes. It was generally
agreed that the more detailed top-level diagrams in Part 3 would be a very worthwhile
improvement, and WG7 suggested to Bill that he develop a CP for these new
diagrams to discuss in a subsequent meeting. It was also agreed that the more
detailed diagrams would be a very useful tool for WG7 to use in developing the
standard, and could potentially be included in Supplement 17 (non-normative) in the
future. These more detailed tools could also be even more useful in the IHE context.
11. NON-AFFINE TRANSFORMATIONS
Scott Johnson presented this work to WG6, at which most WG7 attendees were present.
The supplement will shortly be issued for public comment.
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12. IEC COORDINATE SYSTEMS
Uli reported that IEC are comfortable with the Table Angle Proposal, for inclusion in the
second amendment. Uli will try and have the gantry pitch included in this amendment also.
13. ZEROCONF
There were no volunteers to continue this work. The item will be removed until there is any
new progress or enthusiasm for this work.
14. CURVE MODULE
WG7 considers that this work is still important, particularly for standalone overlay data
associated with RT Image sets. WG7 members are invited to review Jeff’s documents in the
inbox of the WG7 Denver 2005 meeting (“Out with the Curves” and “Out with the Curves
Part 2”), and potentially come up with further argumentation and comment for discussion at
a future WG7 meeting.
15. RT TREATMENT COURSE DEVELOPMENT
Currently there is a Treatment Course proposal available, but little work has been done in
recent times. WG7 considers that this work is very important, especially the prescription
aspect. An RT Treatment Course object is important for the planning process in particular,
and could potentially be part of an IHE-2008 demo involving an expanded worklist
(addressing the simulation and planning process, for example). RT Treatment Course will
also be critical for certain types of adaptive planning. Time will be allocated at the AAPM or
ASTRO meetings if Uli or other individuals can advance the state of the draft. It would be
very useful to recast the work into a conventional DICOM Supplement format.
16. OTHER BUSINESS
Bruce mentioned that there may be work on cone beam CT starting, as part of WG2. Some
WG7 members may wish to get involved in this work. Bruce will investigate and report back.
See WG2 minutes of October 2005.
17. NEXT MEETINGS
Supplement 74: First T-con on Wednesday 15 February 2006, EST (D.C.)
August 3-4, 2006 (Orlando)
November 9-10 (Philadelphia)
18. ADJOURNMENT
The meeting recessed at 6:00 p.m. on January 23, reconvened at 9:00 a.m. on January 24.
At 12:00 noon on Jan 24 the meeting recessed. Most of the group members (including the
Secretary) traveled to Arlington, VA and participated in the WG-06 meeting from 1:30 p.m.
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to 5:30 p.m. discussing the updated CP’s, Supplements 74 and 102. The Meeting
reconvened at 9:00 a.m. on Jan. 25 and adjourned at 12:00 noon on Jan. 25.
Reported by
Stephen Vastagh, Secretary
2006-02-08
REVIEWED BY COUNSEL: CRS 2/14/06
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