1. 2nd Generation Radiotherapy
Supplement RT Physicians Intent and RT Segment Annotation Trial Implementation
Ulrich Busch
Chairman DICOM WG-07 Radiotherapy
Varian Medical Systems Systems Analyst Baden, Switzerland

2. Outline 2nd Gen RT Overview and Status Physician’s Intent Use Cases
Architectural Principles
Physician’s Intent
Conceptual Volumes
RT Segment Annotation
Trial Implementation and Next Steps

3. 2nd Generation Supplements
Number
Supplement Name
Status
147
Second Generation Radiotherapy - Prescription and Segment Annotation
Public Comment Period ended
Reading for Trial Implementation
175
Second Generation Radiotherapy – C-Arm RT Treatment Modalities
In Public Comment Due date: December 31, 2016
176
Second Generation Radiotherapy – Additional RT Treatment Modalities
Ready for Reading with WG-06 for Public Comment.
177
Second Generation Radiotherapy – RT Dose Objects
Partially reviewed by WG-06 In preparation for Public Comment
178
Second Generation Radiotherapy – RT Course
Draft
Partially reviewed by WG-06
179
Second Generation Radiotherapy – RT Explanatory (Part 17)
Not yet presented to WG-06
nn1
Second Generation Radiotherapy – RT Radiation Record

4. Supplement Process

5. Status of Sup 147

6. RT Physicians Intent Use Cases

7. Sup 147 Use Cases
Patient Transfer
Hospital A Hospital B

8. Sup 147 Use Cases TPS to TPS Treatment Phase 1 Treatment Phase 2
Vendor A Vendor B Brachytherapy Proton Planning System Planning System

9. Sup 147 Use Cases
Trial Submission

10. Sup 147 Use Cases
Archive
… patient discharge

11. Sup 147 Use Cases
Get Patient Treatment History
… recurrence

12. 2nd Generation Architectural Guidelines

13. Architectural Guidelines
Support Clinical Advances
Rich Model of Prescription
 Physician Intent IOD
Address Adaptive Treatments
Powerful Models to track
Targets, Patient Anatomy
 Conceptual Volumes
Support of various Segmentation Formats
Enable use of any non-RT Segmentation (besides RT Structure Set: Segmentation IOD, Surface IOD, etc.)
Decorate any IOD by RT Semantics (Target, OAR, Devices, Properties like Densities, …):
 RT Segment Annotation IOD

14. Architectural Guidelines
Support of highly dynamic Workflows
Frequently optimized treatments
Entities have their distinct workflow-lifetime
Prescription
Segmentation
Treatment Parameters
Patient Positioning Procedures
Treatments Artifacts for monitoring course of treatment
No Monster RT Plan IOD any more
Lighter and dedicated IODs
Optimized to handle various use-case scenarios

15. Architectural Guidelines
Data Interpretation / Data Mining
Robust Formalism
Well-defined meaning
Extensibility enabled
No inconsistencies due to free-text labeling
Local Language support
Extensive use of Codes

16. Architectural Guidelines
Flexibility for future expansion
… pathway to
new prescription content
Expandable parts of RT Physician Intent IOD
new treatment approaches
new segmentation methods
RT Segment Annotation IOD
new treatment devices
new treatment techniques
new positioning and tracking methods
Concepts for Radiation IOD (* ‘Radiation IOD’ as general term of other supplements: represents separate IODs optimized for different treatment devices)

17. Trial Scope

18. RT Physicians Intent IOD

19. Physician’s Intent Intent Label and Narrative (Free Text)
Protocol (Coded)
References to
Diagnostic Images
Clinical Documents, Reports
0 - n Diagnostic Codes
Currative, Pallative, Prophylactic
Predecessor References

20. Physician’s Intent Targets / Anatomic Volumes
Admission of Conceptual Volumes
For each Volume: Without concrete segmentation Or already based on one or more segmentations
Types like:
PTV, CTV, GTV, ITV
OAR, PRV, Avoidance, Dose Shaping
(coded – extensible)
Clinical Coding
Various Characteristics
Overlapping Region Precedence
Upstream, downstream Blocking
Anatomic Coding

21. Physician’s Intent Major Planning Parameters Treatment Technique
Fractionation Definition (# of Fx, Pattern, Notes)
Radiation Type Photon, Electron, Ions, Brachy Isotopes

22. Physician’s Intent Dosimetric Objectives
Applicable for Targets and OAR as appropriate
(Coded – extensible)
Currently Defined Objectives
Simple Dose Parameters: Minimum, Mean, Maximum Dose: e.g. “PTV50: Target Dose 50Gy”
Combined Dose Parameters: Min / Max Percentage at Dose (like “Bladder: 40Gy <= 60%) Min / Max Volume at Dose
Conformity Indices
some others
Upcoming Objectives of Interest
Will be added as needed

23. Physician’s Intent Narratives Beam Shaping Means
Special Procedure Note
Patient Positioning Note
Motion Compensation Note
Patient Setup Note
Planning Imaging Note
Delivery Verification Note …

24. Conceptual Volume

25. Conceptual Volume Abstract identification of an anatomical object
Identifies any anatomic regions
Allows tracking targets and organs
Along any set of images acquired throughout the course of treatment
Can be utilized without any Segmentation
Definition can be deferred to later stage of workflow:
Define Goals and Constraints for Targets and Organs at Prescription Time
Perform contouring afterwards

26. Conceptual Volume Abstract identification of an segmented object
Supports combinations
Combine other CVols
Don’t segment the combinations
Track combined Volumes
Track dosimetric information against Conceptual Volumes
DVH
(Nominal) Dose Values

27. Prescribe 20Gy to the tumor.
CV - Admission
Diagnostic CT
CVol I
”Tumor“
Physician Intent:
Prescribe 20Gy to the tumor.
RT Structure Set
- Region of Interest 1, “Lesion“ MR

28. CV - Change CV I “Tumor“ RTStructSet 1 - ROI 1, “Lesion“ RTStructSet 2
- ROI 4, “Target“
RTStructSet 3
ROI 2,
“PTV“ MR
CBCT 1
CBCT 2
Day 10
Day 20

29. - Region of Interest 5, “Left Lung“
CV - Combination
CV I
“Lung, left“
CV II
“Lung, right“
CV III
“Lungs“
RT Structure Set
- Region of Interest 5, “Left Lung“
Segmentation Storage
Segment 9,
“Lung, r“

30. RT Segment Annotation IOD

31. RT Segment Annotation  RT Segment Annotation IOD
RT Structure Set is not always optimal
Alternate IODs for Segmentations are defined in the Standard and in use
E.g. - Segmentation Storage (3D volume) - Surface Segmentation Storage (3D mesh surface)
Three Issues to address for generalized use of segmentations:
Relate segmentations to Conceptual Volumes
Only RT Structure Set has specific Radiotherapy semantics: other segmentation objects are designed for general purpose, not RT
Enable use of various IODs in RT Objects: generalized facade for referencing:
From: RT Objects (Prescription, Dose etc.)
To: various IODs containing segmented content
 RT Segment Annotation IOD

32. RT Segmentation RT Categorization Structure Template References
Target, OARs, etc.
Structure Template References
Recommended Display variables
For segmented RT Devices:
(Bolus, Couch, Setup / Fixation Devices…)
Device types and identification
Segment Characteristics
Densities Properties (Mass, Electron)
Atomic Numbers (Z, A)
Elemental Composition
Cell Kill Factors
… more to come as needed

33. RT Segmentation All 2nd Gen RT Objects reference RT Segment Annotation
… and no longer RT Structure Set only
Key construct to support Adaptive Therapy
Tracking of Targets and Organ
…along the whole course of Treatment
Prescription
Segmentation
Treatment Planning
Treatment Delivery
Treatment Monitoring

34. Adaptive Example

35. Why now 2nd Generation ?

36. This applies to RT now, after 20 years of 1st Gen
Why 2nd Generation ?
Who would like to go back to the times of vendor-specific CT Formats or no RT in DICOM?
Most devices were covered somehow, so why going for DICOM?
Always the same question once it is time for renovation.
Doing nothing = Technical Depth accumulates
= Development cost, Maintenance costs, Service costs … increase
This applies to RT now, after 20 years of 1st Gen

37. Why 2nd Generation ?
Some (not all) areas of interoperability are somehow working
in 1st Gen.
Yet…
increasingly cumbersome and differing implementations
not very efficient
not designed for today’s dynamic workflow (Continuous Adaptation to accommodate Disease Response)
lack of precision needed for data mining and safety
Some areas not addressed at all:
Physicians Intent
Conceptual Volumes
Use of Segmentation IODs Surface IODs etc.
New Treatment Devices not covered (and no way to extend the Standard efficiently)

38. Why 2nd Generation ? Enhanced Clinical Capability will need
2nd Generation RT:
Detailed prescription sharing
Prescribed Volumes cross-referenced throughout the clinical process for tracking and adaptation
Complex or high resolution structure sharing
Highly adaptive positioning and treatment

39. Trial

40. Why Trial ? Completely new IODs and Concepts:
Physician’s Intent IOD
RT Segment Annotation IOD
Conceptual Volume
Nothing comparable in 1st Generation
Trial needed for Sup 147
… no Trial may be needed for other Supplements like
Radiation Set IOD (175, 176)
Radiation IODS (175, 176)
Dose (177)
Substantial Modernization – yet no completely new concepts
 will be defined by WG-07

41. Goals of Trial
Test correctness, clarity, completeness of the Standard Specification
Explore and evaluate the new DICOM objects
Get familiar with those Objects
Exchange Knowledge and best practices

42. Trial Provisions No Productive Use Path to go:
Conduct Trial (Mid 2017)
Address Findings (End 2017)
Add to DICOM Standard (2018)
…effective timeframes will depend on intensity and pace of participation in trial
 Ready to use

43. Trial Implementation Outline
Timeframe:
First Half of 2017
Activities
1. Production of Samples
Physician’s Intent
RT Segment Annotation
- using RT Structure Set IOD
- using Segmentation IOD
2. Discussion of Samples
Gaps?
Specification Lack of Clarity?
Syntactical Issues?
… anything else

44. Next Steps …set off your Participation: Feb. 7, 2017 11am - 1pm
Project Resources
Timeframe 1/2017 – 6/2016
Internal Kick-Off can already be started right now:
Familiarize with Sup 147
Decide on data scope of implementation (e.g. have a look at IHE-RO Prescription Profile)
Ask any questions anytime
Individual training session can be provided
Kick-Off TCon
Audience: Participating engineering resources
Feb. 7, am - 1pm

45. Enough of Paper Work …
Let’s go

46. References http://dicom.nema.org/ http://www.HL7.org/

47. Contacts Ulrich Busch Christof Schadt
Editor, Chair WG-07
Varian Medical Systems
Christof Schadt
Vice-Chair WG-07
Brainlab AG
Trial Implementation Group Communication
To Be Defined