Title: DICOM%20Anniversary%20Conference%20Experience%20Using%20DICOM-RT%20Objects%20for%20Clinical%20Trials%20QA
1DICOM Anniversary ConferenceExperience Using
DICOM-RTObjects for Clinical Trials QA
- Walter R. Bosch, D.Sc., John W. Matthews, D.Sc.,
- Vincent A. Frouhar, Ph.D., Jatinder R. Palta,
Ph.D., - James A. Purdy, Ph.D.
2NCI Advanced Technology QA Consortium
- Members
- Image-guided Therapy Center (ITC)
- J. Purdy, W. Bosch, J. Matthews, Wm. Straube, J.
Michalski - Resource Center for Emerging Technologies (RCET)
- J. Palta, V. Frouhar, J. Dempsey
- Radiological Physics Center (RPC)
- G. Ibbott, D. Followill
- Radiation Therapy Oncology Group (RTOG)
- E. Martin, R. Lustig
- Quality Assurance Review Center (QARC)
- T.J. FitzGerald, M. Urie, K. Ulin
- Support
- NIH U24 grant CA81647, Advanced Technology QA
Center
3NCI Advanced-Technology QA Consortium
- History
- Created in 2002 (in its current form) by NCI to
support QA for advanced technology clinical
trials (P.I. J.A. Purdy, Ph.D.) - Builds on a decade of experience in supporting QA
for clinical trials involving 3DCRT and IMRT
- Mission
- Develop appropriate and uniform QA procedures and
criteria - Facilitate sharing of developmental and QA
resources for digital data submission and review
4Dose-Response Modeling in Radiotherapy
- Fundamental trade-off
- deliver tumoricidal dose to a target
- avoid injury to radiosensitive normal tissues
(organs at risk) - Normal-tissue tolerance doses in current use are
based on simple point doses and do not account
for dose-volume effects. - Correlating volumetric doses with clinical
outcomes is expected to yield better
dose-response models for normal tissue.
5Digital Data for Advanced-Technology Clinical
Trials in Radiotherapy
- Primary data (volumetric dosimetry)
- Volumetric Image (CT)
- Structure Set GTV, CTV, PTV, OAR
- 3-D Dose Distribution (including fractionation
information) - Secondary data (QA of primary data)
- Treatment Plan Specification
- Dose-Volume Histograms
- Digital Simulator and Portal Images
6Digital Data Submission for Advanced-Technology
Clinical Trials
- Treatment planning data are stored in proprietary
formats. - For meaningful exchange of information, we need a
common data representation and interchange
format. - RTOG Data Exchange Format
- Based on AAPM Report 10
- Used to exchange of treatment planning data in
RTOG advanced technology protocols, starting in
1994. - Over 1600 protocol data sets submitted to date.
7RTOG Advanced-Technology Protocols
RTOG Protocol Site Status Approved Institutions Accrued Cases
9406 Prostate Ph I/II Closed 53 1084
9311 Lung Ph I/II Closed 26 180
9803 Brain (GBM) Ph I/II Closed 46 210
H-0022 Oropharynx IMRT Ph I/II Open 13 25
H-0225 Nasopharynx IMRT Ph II Open 13 2
L-0117 Lung Ph I/II Open 34 14
P-0126 Prostate Ph III Open 79 146
P-0232 Prostate Brachytherapy Ph III Open 5 0
BR-0319 Breast Ph I/II Open 8/15 0 0
as of 9/16/2003
8Why Use DICOM to Represent Radiotherapy Treatment
Planning Information?
- Broadly-based industry standard
- Support for current and future imaging and
treatment modalities - PET
- Functional MRI
- External beam IMRT
- HDR brachytherapy
- Heavy-particle therapy
9History of the DICOM RT Objects
- November 1994 DICOM Ad Hoc Committee on
Radiotherapy Objects met at RSNA - June 1997 Supplement 11 approved
- RT Structure Set
- RT Plan
- RT Dose
- RT Image
- May 1999 Supplement 29 approved
- RT Treatment Record
10DICOM RT Objects Needed for Advanced Technology
Clinical Trials
- A participant must submit a complete,
protocol-compliant data set CT Image (MR Image,
US Image), RT Structure Set, RT Dose, RT Plan,
and RT Image. - Many clinical implementations support only a
subset of the RT objects. Typical external-beam
TPS - Only recently have commercial treatment planning
systems begun to export this complete set of
objects.
11Special Requirements for DICOM Attributes for
Clinical Trials
- Type 3 attributes may not be present.
- Not meaningful in all applications
- Incompletely specified objects at early stages of
the planning process - Special requirements for attributes values, e.g.,
- RT Plan Geometry (300A,000C) must be PATIENT.
- CT and MR images must have square pixels.
- The ATC Fileset Reader application Conformance
Statement (http//itc.wustl.edu) lists required
attributes and special requirements for attribute
values.
12RT Dose Object Implementation Issues
- Single, multi-frame dose object vs. many, planar
dose objects - Grid Frame Offset Vector
- Absolute axial coordinate of dose grid plane
- Relative offset of dose grid plane from Image
Position (Patient) attribute value. - 32-bit Dose Values
- Byte-order and word-order issues
13Maintaining Consistent Object Linkage
- DICOM RT objects reference each other.
- Structure Set references images (Frame of
Reference) - Plan references Structure Set
- References are important for automated import.
- Submission software should check that references
are correct and complete.
14Clinical Trials Identification
- Data for a clinical patient must be de-identified
and associated with a clinical trial subject. - DICOM Supplement 70 (Jan. 2003) introduces
Clinical Trials ID modules which include 10 new
attributes that can be added to any DICOM object
to identify - Clinical trial sponsor
- Clinical trial protocol
- Clinical trial subject
15Submission of DICOM Data to the ATC
- Part-10 Filesets (currently supported)
- CD-R media
- FTP to ITC server (like RTOG Data Exchange)
- ATC Submission System (in development)
- Push DICOM data to WebSys client program (DICOM
Storage SCP) on local PC - Replace patient ID with clinical trials ID
- Perform secure upload to ATC server
16Credentialing for Participation in Advanced
Technology Clinical Trials
- Institutions must pass a dry run (benchmark)
test by submitting a protocol-compliant data set
to the ATC. - Treatment planning systems are said to be ATC
compliant when a complete data set received from
a real, clinical user is judged to be
protocol-compliant.
17Institutions Credentialed for RTOG Protocols
using DICOM RT
Protocol Institutions Credentialed
P-0232 Prostate brachytherapy 5
H-0022 Head-neck IMRT 1
P-0126 Prostate 3DCRT 1
as of 9/16/2003
18ATC Efforts to Support DICOM Implementation for
Clinical Trials
- DICOM Implementers Technical Workshops
- March 16-17, 2001
- March 16, 2002
- May 3, 2003
- Spring 2004
- Assistance in evaluating compliance of data sets
- Feedback to implementers via the web-based Remote
Review Tool
19Remote Review Tool
- CT Images (zoom, window/level)
- Structure contours (review, editing)
- Iso-dose contours
- Interactive DVH
- Point-dose display
20Conclusions
- Advanced-technology clinical trials are
attempting to correlate volumetric dosimetry
information with clinical outcomes. - Expected to yield improved dose-response models.
- Requires volumetric digital data
- The DICOM RT objects are becoming a viable option
for submission of data in these studies. - ATC compliant treatment planning systems are
listed on the ITC website http//itc.wustl.edu .
(ATC website coming in Fall, 2003.)