Radiation Exposure Monitoring(REM) Profile

Kevin O’DonnellToshiba Medical Research Inst. - USACo-chair, IHE Radiology Planning Cmte

IHE Radiology

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MotivationMotivation• X-Ray based imaging can provide tremendously

useful information

• Patient Dose is an important consideration

• Potential benefit > potential risk … but risk should be managed responsibly

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A New IHE ProfileA New IHE Profile• IHE Radiation Exposure Monitoring Profile – Integration of systems reporting dose and systems

which receive, store, or process those reports– Modalities, PACS, RIS, Workstations, Registries

– Facilitate compliance with Euratom 97/43,ACR Guidelines, etc.

– Directly based on DICOM Dose Reports

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IHE Radiation Exposure Monitoring ProfileIHE Radiation Exposure Monitoring Profile

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National Registry

ArchiveDose Information

Reporter

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Outlier: #Performing Phys.Over Target: 12.2%

Outlier: #Performing Phys.Over Target: 12.2%

Outlier: #Performing Phys.Over Target: 12.2%

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REM Profile: Actors & TransactionsREM Profile: Actors & Transactions

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DICOM Dose ReportsDICOM Dose Reports• “SR Objects” – DICOM Structured Reports– Easily ingested (and regurgitated) by PACS

• Granularity : “Irradiation Event”– & Accumulated Dose over Study, Series

• Templates : – CT, Projection X-Ray (Mammo, Fluoro)– DR/CR

• Not yet addressed: NM, RT

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Key MeasurementsKey Measurements• CT Dose– DLP, CTDIvol, kVP, mA, sec– Effective Dose [ Optional ]

(Reference estimation method)

• Projection X-Ray Dose– DAP, Dose@RP, kVP, mA, sec– Fluoro Dose, Fluoro Time

• Mammography Dose– AGD, Entrance Exposure@RP, kVP, mA, sec– Compression, Half Value Layer

ftp://medical.nema.org/medical/dicom/2009/09_16pu.pdf

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Other Details in Dose SROther Details in Dose SR• Full Patient / Order / Study Details• Unique ID for each Irradiation Event• Equipment ID, Ordering Doc, Performing Tech

• Patient Position, Anatomy imaged• Imaging Geometry (projection)

• Collimation• X-Ray Filters, Anode Target Material• Calibration, Phantom, Dosimeter

DICOM SR TemplateDICOM SR Template

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Creating SR Dose ReportsCreating SR Dose Reports• Modalities– CT, XA/XRF, X-Ray, Mammography

• “Readers”– CR, DX, Film Digitizers– Note challenge if tube and detector don’t talk…

• 3rd Party Workstations

• RIS, PACS

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Storing SR Dose ReportsStoring SR Dose Reports

• Usually stored in the Study folder– Archive, Backup, Reconciliation– Query / Retrieve

• Can be sent to other destinations

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Using SR Dose ReportsUsing SR Dose ReportsPossible applications:• Radiation QA

– Periodically Query / Retrieve Reports from Archive– Set policies/standards and flag deviations– Set goals for improvement and track; – Implement protocol changes and compare difference in dose

• Patient Impact Evaluation– e.g. if Patient identified as pregnant post-facto

• Dose Mapping– Store data in realtime from Modality to Mapping Workstation

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Using SR Dose ReportsUsing SR Dose Reports• National Registries– Anonymize and submit Dose Reports to Register– Compile Population Risk Estimations– Derive Dose Reference Levels– Provide Site-Site Comparisons

• Individual Dose Record– Collect Dose Reports over time

• Clinical Trials– Collect Dose together with Images– Demonstrate both improved detection & reduced dose

IHE REM Changes• Final Text CPs

– CP195 - Internationalize Series Description (RAD-62)– CP197 - Replace Register with Registry– CP198 - Remove weakening of DICOMDIR (RAD-63)

• Almost Final Text CPs– CP196 - REM De-identification (RAD-63)– CP199 - Patient Longitudinal Record Use Case– CP200 - Alternative Submission Transport Mechanisms (RAD-63)– CP203 - Require Irradiation Event UID in Images– CP204 - Record Patient Characteristics in Dose Reports

( See www.ihe.net/Technical_Framework/ )

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DICOM SR ChangesDICOM SR Changes• Incorporated CPs

– Use DICOM 2009 PS3.16 – incorporates CP-874 and more

• Final Text CPs– CP-957 – Add CT Exposure Modulation Type– CP-963 – Add DateTime Started to Irradiation Event

• WIP CPs– CP-1063 – Clean-up Dose Reports– CP-1065 – Improve Device Identification– CP-1068 – CT Scan Location– CP-1070 – Additional Codes for Dose Information Source– CP-1075 – CT Dose for Constant Angle Acquisitions– CP-1076 – Fix participant relationship in TID1020– CP-1077 – CR Dose Report

( See dclunie.com/dicom-status/status.html )15

Profile Overviews:Profile Overviews:wiki.ihe.net/index.php?title=Profiles

Profile Specs.:Profile Specs.:www.ihe.net/Technical_Framework

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Why not use Image Headers?Why not use Image Headers?

• Mostly Exposure details (for interpretation)

• No image; no dose– deleted due to quality / patient motion

• More images; more dose– extra reconstructions; post-processing

• Lacks complete dose details

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Why not use MPPS?Why not use MPPS?

• Modality Performed Procedure Steps– Status messages back to RIS / PACS

• Transient Information– designed for workflow; not persistent archiving

• Lacks complete dose details