DICOM Second Generation Radiotherapy Objects Part 1 Supplement 147: Physicians Intent and Segment Annotation We are here to present the first public information of the DICOM Second Generation Radiotherapy Objects. These objects are being submitted and reviewed by the DICOM Working Group over 6 supplements. The first to be approved for public comment is Supplement 147, which covers Physicians Intent and Segment Annotations. The others –   175 Second Generation Radiotherapy – C-Arm Radiations 176 Second Generation Radiotherapy – New RT Radiations 177 Second Generation Radiotherapy – Dose Objects 178 Second Generation Radiotherapy – RT Course 179 Second Generation Radiotherapy – RT Explanatory (Part 17)

Ulrich Busch Systems Analyst with Varian Medical Systems Member of DICOM WG-07 since 2000 Chairman of DICOM WG-07 since 2011 Member of the IHE-RO Technical Committee since 2005 Uli has a long history with DICOM, and is currently the Chairman of DICOM Working Group 7, the RT group under DICOM. DICOM Second Generation Radiotherapy

Christof Schadt Software Principal with Brainlab AG Member of DICOM WG-07 since 2005 Vice-Chair DICOM WG-07 since 2011 Member of the IHE-RO Technical Committee since 2005 Christof Schadt is the Vice-Chair of Working Group 7, and his company has already made some exploratory efforts at implementing some of the Second Genration objects. DICOM Second Generation Radiotherapy

Outline Outline Overview : All of Second Generation Discuss the particulars of Supplement 147 Physician Intent Segment Annotations Touch on the Other Supplements that make up Second Generation Next steps Today, we will cover the following topics: a very cursory overview of the Second Generation Objects as a group Discuss the particulars of the first supplement Touch on the other supplements Next steps Our goals are to give a varied audience some of their first introduction to these items, to give some time for questions and reactions, and to help guide any general ideas on how implementation may proceed and what value it would have. DICOM Second Generation Radiotherapy

Introduction New Supplements to DICOM Standard Defined by manufacturers and clinicians Supports and/or influences new technologies and thus new products The DICOM Second Generation objects are described in a series of supplements to the DICOM standard. They are the outcome of a long effort by manufacturers and clinicians from many RT companies and clinical sites. In a broad generalization, the Second Generation objects support old and new RT technology and approaches, more strongly supports workflow, and implements an extensible framework to allow future technologies to operate with DICOM RT DICOM Second Generation Radiotherapy

DICOM Second Generation Radiotherapy DICOM WG-07 One of the DICOM Standards Committee’s (DSC) Working Groups Focus on maintenance and further development of Radiotherapy extensions of the DICOM Standard (“DICOM RT “) Current (regular) industry members: Accuray, Brainlab, Elekta, IBA, Mevion, Philips, RaySearch, Varian (and others) Introduction to „who is DICOM WG-07“ Explain main work DICOM Second Generation Radiotherapy

DICOM Second Generation Radiotherapy What is DICOM RT? DICOM RT is just DICOM ‘RT’ indicates the DICOM objects dealing with RT. Current release of RT Objects is now known as ”1st Generation RT“ (Gen1) Talk to slide…indicate that the DICOM RT label has stuck because the first RT specific objects were introduced through one large supplement. In fact, RT uses, and has proposed objects that are used by other disciplines, such as CT Image and Segmentations. There is no “wall” between RT objects and other DICOM objects. DICOM Second Generation Radiotherapy

DICOM Second Generation Radiotherapy Supplements are about 270 pages created by DICOM WG-07 Worked on for over 7 years Major re-structuring of Gen1 RT objects DICOM Second Generation Radiotherapy

Why now 2nd Generation? Introduction – Full RT Second Generation Object Suite Initial definitions are not sufficient to describe new technologies Use of workflow management will be a focus for the future Some definitions needed to be strengthened or restructured for the best utility Explain in general what this talk is about (no details) DICOM Second Generation Radiotherapy

DICOM Second Generation Radiotherapy Why now 2nd Generation? Advances in Radiotherapy Modern Clinical Flow Continuous Adaptation to accommodate Disease Response Dynamic Processes need Flexibility in Interoperability New Treatment Modalities Stronger Capability to represent the Clinical Workflow Systematic approach for Non-Volumetric and Volumetric Information Design of Modality-Independent versus Modality-Specific Information Electronic Workflow Management Modernization, Efficiency, Systematics (not handled in this Presentation, e.g. Macros as Building Blocks, Optionality, Use of Latest Standard Capabilities, Integration of non-RT Objects) New Treatment Techniques: Adaptive radiotherapy Tomotherapeutic treatments New Treatment Machines: Non-isocentric machines Robotic machines Additional degrees of freedom New positioning techniques Positioning as of today is an integral part of treatment (currently not really reflected in 1G) For all of this Workflow Management could be used to prevent manual errors. The use of current DICOM RT is widespread and growing exponentially so now does not seem like a good time to restart. The practice of Radiation Therapy has advanced over the life of the RT part of the standard and there are key things we can not do, or do well, with the current set of DICOM objects: Prescriptions can not be adequately defined and transferred unambiguously with useful content from one system to another. Adaptive planning : DICOM data that belongs together is not easy to gather and consolidated. We have to make assumptions about the use of DIOM Series and Studies. Ever changing structures and updating treatments are inefficient to create and difficult to track in the current standard. The progress of an adapted set of organ definitions or treatments is clumsy, if not impossible, to track with the large contour and plan models we have in the first generation. The form of these objects were what was intended but we now need to break them apart so that we can keep data that is not changing separate from that which is and provide the referencing that will allow us to track prescription, patient or plan modifications over time. Complex 3D objects are difficult to encode as 2D contours and can be ambiguous about the meaning of their contours (eg donut shapes). New types of non-isocentric machines cannot be accommodated in the current isocentric C-Arm Linac model; for example, Tomotherapy, GammaKnife, CyberKnife The current status of a patient model or treatment, whether it is pending approval, under treatment or done with treatment could not be tracked easily in the DICOM objects. By removing the state of an object from its content we don’t have to update and create new DICOM objects every time it changes from new to approved, for example; likewise, we don’t then have to update objects that reference that one. As has happened in other DICOM areas like Radiology, DICOM services like Unified Procedure Step have come into play where orders can be placed, orders can be acknowledged and procedures can be reported back to a central authority in the enterprise. DICOM 2nd generation anticipates this and builds this into the assumptions for the new data objects. DICOM Second Generation Radiotherapy

DICOM Second Generation Radiotherapy Focus RT Process Perspective was Too Narrow 1st Generation: Result of Treatment Planning System 2nd Generation: Incorporating complete Treatment Workflow One other way to view the transition… DICOM Second Generation Radiotherapy

2nd Generation Object Overview DICOM Second Generation Radiotherapy

RT Course Represents an RT Treatment Course May contain several treatment phases Is a container collecting all major objects which are relevant to this course Try to limit discussion on this. DICOM Second Generation Radiotherapy

DICOM Second Generation Radiotherapy RT Physicians Intent Describes how to achieve the curative or palliative therapy Total and fractional doses, fractionation schemes, treatment sites, dosimetric objectives and other information is included We will get into more detail in this presentation. DICOM Second Generation Radiotherapy

DICOM Second Generation Radiotherapy Conceptual Volume Description of an anatomical region or point, which may or may not be associated to one or more volumetric representations Also in this presentation…. DICOM Second Generation Radiotherapy

DICOM Second Generation Radiotherapy RT Segment Annotation Represents RT specific annotations on a Segmentation, Surface Segmentation or RT Structure Set In this presentation. DICOM Second Generation Radiotherapy

RT Radiation Set Defines a radiation therapy treatment fraction, through a set of RT Radiations, which may be applied one or more times. Now handles newer technologies, and is extensible. DICOM Second Generation Radiotherapy

RT Radiation Record Records actual treatment parameters and attributes Now handles newer technologies and is extensible. DICOM Second Generation Radiotherapy

RT Dose Image Represents a 3-dimensional dose distribution using the multi-frame and functional group paradigms. DICOM Second Generation Radiotherapy

RT Dose Histogram Describes a dose-volume histogram Based on a volumetric dose calculation References a Conceptual Volume and an RT Segment Annotation DICOM Second Generation Radiotherapy

RT Dose Samples Represents dose point data, which are calculated or measured. DICOM Second Generation Radiotherapy

RT Treatment Phase A Course can be divided into multiple RT Treatment Phases Each Phase represents an attempt to reach a treatment goal via RT Radiation Sets DICOM Second Generation Radiotherapy

Solution: Dynamics Workflow Enabled Because we have dedicated objects Still possible to work with or without DICOM Worklist Volatile Information outside objects Status information Dynamic Relations Addressed By UPS and usage of RT Course IOD (Companion objects?) DICOM Second Generation Radiotherapy

Architectural Principles I Use new approaches already defined in DICOM Volume and Surface Segmentation Rigid and Deformable Registrations Some smaller Items (esp. Macros) Object-oriented approach Cohesive objects with different, specific intents Avoid “Monster” objects, or inappropriate encapsulation (Plan/RX) New approaches: Now there are lots of things to build on top Contrary to 1G, where there mainly were images OO: Reduce to what is really necessary Factor out separate capabilites DICOM Second Generation Radiotherapy

Architectural Principles II Flexibility for future expansion e.g. open for New treatment machines New segmentation methods New treatment techniques New positioning and tracking approaches DICOM Second Generation Radiotherapy

Supplement 147 – Prescription and Segment Annotation DICOM Second Generation Radiotherapy

DICOM RT Plan Issues Prescription Module is not precisely documented Cannot exist outside an RT Plan object Does not represent current technologies well Links to volatile information (Imaging) Prescription Fractionation Beams Patient Setup DICOM Second Generation Radiotherapy

RT Physician Intent Contains the following parts: Physician Intent Mostly free-text definition of the physician‘s intent based on a diagnosis Prescription Actual prescription parameters Treatment Phase Intent How the time structure of the delivery is intended Exists outside of the RT Plan Supports real-world timing of Prescription information overall intent of the treatment. mostly descriptive text freely formulated advice prescription(s) for a specific target. Treatment phases define the intended time structure of the prescribed treatment (Question: how will the legacy Rx information and objects be handled?) DICOM Second Generation Radiotherapy

RT Physician Intent Modules IE Module Reference Usage Include 'RT Second Generation IOD Modules Macro' Table A.VV.1.1.1-1 RT Physician Intent C.AA.B1 M RT Prescription C.AA.B2 U RT Treatment Phase Intent C.AA.B3 C Required if RT Treatment Phase Intent Presence Flag (30xx,0808) equals YES. overall intent of the treatment. mostly descriptive text freely formulated advice prescription(s) for a specific target. Treatment phases define the intended time structure of the prescribed treatment DICOM Second Generation Radiotherapy

RT Physician Intent Modules overall intent of the treatment. mostly descriptive text freely formulated advice prescription(s) for a specific target. Treatment phases define the intended time structure of the prescribed treatment The intent module is more “free form”.. The prescription module now ties specifics to conceptual volumes, which may or may not be related to segmented volumes… Treatment phase describes the time frame and fractionation Diagram B is the Conceptual Volume reference DICOM Second Generation Radiotherapy

Conceptual Volume (CV) Abstract object Identifies anatomic region May be a combination of other CVs Can be utilized without any Segmentation Definition can be deferred to later in workflow DICOM Second Generation Radiotherapy

Conceptual Volume Modules

Prescribe 20Gy to the tumor. CV Example Diagnostic CT CVol I ”Tumor“ Physician Intent: Prescribe 20Gy to the tumor. RT Structure Set - Region of Interest 1, “Lesion“ Physician reviews a diagnostic CT, with a Tumor volume. Generically, first prescribes 20Gy…. An MR is ordered, and separately this is used to Segment a “Lesion” structure, to which the Conceptual Volume is linked MR DICOM Second Generation Radiotherapy

CV Consistency vs. Change CV I “Tumor“ RTStructSet 1 - ROI 1, “Lesion“ RTStructSet 2 - ROI 4, “Target“ RTStructSet 3 ROI 2, “PTV“ Adaptive! In this example treatment begins, but further refinement to the treatment occurs. Using cone beam CTs as a basis, further volumes are defined and given treatment parameters. MR CBCT 1 CBCT 2 First Day Day 10 Day 20

CV Combination CV I “Lung, left“ CV II “Lung, right“ CV III “Lungs“ Another example: it’s anticipated that CVs can be handled in abstract in single and in group references…with different modalities supplying the underlying data that allows linkage to a specific segmentation. RT Structure Set - Region of Interest 5, “Left Lung“ Segmentation Storage Segment 9, “Lung, r“ DICOM Second Generation Radiotherapy

RT Segment Annotation Modules “Removes… “- e.g. clinical target volume, organ at risk, bolus, density overrides „What is it“ vs. „What does it mean“ DICOM Second Generation Radiotherapy

RT Segment Annotation Separates the RT-specific information from the actual data CTV, PTV, OAR, … Bolus Density Overrides Structure is represented by existing DICOM objects Segmentation Storage (3D volume) Surface Segmentation Storage (3D mesh surface) RT Structure Set (Contour lines – Gen1) Others “Removes… “- e.g. clinical target volume, organ at risk, bolus, density overrides „What is it“ vs. „What does it mean“ DICOM Second Generation Radiotherapy

Other Supplements 175 – C-Arm Radiations 176 – New RT Radiations 177 – Dose Objects 178 – RT Course 179 – RT Explanatory (Part 17) “Removes… “- e.g. clinical target volume, organ at risk, bolus, density overrides „What is it“ vs. „What does it mean“ DICOM Second Generation Radiotherapy

How does it affect you? Once these objects appear, manufacturers will need to support both Gen1 and Gen2 during the transition 8 old objects deprecated 24 new objects added The sooner the Gen2 objects are in place, the earlier support for Gen1 can be reduced (or even stopped) RT Dose RT Structure Set RT Image RT Plan RT Beams Treatment Record RT Brachy Treatment Record RT Treatment Summary Record RT Ion Plan RT Ion Beams Treatment Record DICOM Second Generation Radiotherapy

How does it affect you? Enhanced Clinical Capability will need Gen2 Detailed prescription sharing Prescribed Volumes cross-referenced throughout the clinical process for tracking and adaptation Complex or high resolution structure sharing Highly adaptive positioning or treatment DICOM Second Generation Radiotherapy

What will NEMA do to help? Provide introduction presentations Run hands-on engineering classes in Europe and North America Work with IHE-RO to develop the order of adoption for most benefit “The Implementer‘s Guide to 2ndGeneration RT Objects“ by WG-07 members DICOM Second Generation Radiotherapy

Contact Stephen Vastagh Ulrich Busch Christof Schadt DICOM Secretary NEMA/MITA svastagh@medicalimaging.org Ulrich Busch Chairman DICOM WG-07 ulrich.busch@varian.com Christof Schadt Vice-Chair DICOM WG-07 christof.schadt@brainlab.com DICOM Second Generation Radiotherapy

Links NEMA DICOM Page Participate in DICOM DICOM Standard Status http://dicom.nema.org Participate in DICOM http://dicomconference.org/ DICOM Standard Status http://www.dclunie.com/dicom-status/status.html DICOM Second Generation Radiotherapy

Thanks to Christof, Jim Percy (Elekta), Mike Courtney (Philips), Mark Pepelea (Philips), Bruce Rakes (Mevion) for preparing and reviewing the initial content for an AAPM presentation, on which this is based DICOM Second Generation Radiotherapy