radiation dose tracking standards structure tools …radiation dose monitoring: beyond ct (the...

Disclosures • Kevin O’Donnell :

– Employee, Toshiba Corporation

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NEMA XR 29 (2013): Standard Attributes on Computed Tomography (CT) Equipment Related to Dose Optimization and Management NEMA XR 25 (2010): Computed Tomography Dose Check NEMA XR 26 (2012): Access Controls for Computed Tomography: Identification, Interlocks, and Logs NEMA XR 27 (2012): X-ray Equipment for Interventional Procedures User Quality Control Mode NEMA XR 28 (2013): Supplemental Requirements for User Information and System Function Related to Dose in CT

Radiation Dose Monitoring: Beyond CT (The Plumbing Talk)

Presenter: Kevin O’Donnell – Toshiba Past Chair, DICOM Standards Cmte Radiology Rep, IHE International Board

Where’s My Flying Car?

“The future is already here; it’s just not evenly distributed yet.” - William Gibson

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OK, Dose tracking isn’t as much fun as a flying car, but the point is that the tools are available off the shelf today. If you think you should be doing something, there is no excuse not to. Get started.

Dose Tracking in Products • IHE Radiation Exposure Monitoring

– 32 vendors already passed at Connectathons (more again this year) – All major CT vendors were shipping REM support in 2012. – 22 modality products (CT, XA, DR, MG) – 17 archive products, 15 dose “consumer” products – 4 dose reporters, 1 dose registry

• NEMA XR-25 – CT Dose Check – most new products

Time to get started…

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Products exist and have been rolling out over the last few years. The message is: There is no reason not to start now.

What about my legacy CTs?

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Some of you may have old systems.

We’ll talk about that too…

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Don’t let that stop you, we’ll talk about legacy integration strategies too. And if you are already doing all this, write up your experiences, we’d love to have you presenting next year.

Standards & Tools

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You believe managing dose is part of the practice of radiology. What’s your plan? On average, what’s your dose for an adult chest CT without contrast? How are you going to get started? You could give your techs a pencil and a dose log sheet. It’s easy. But it’s not scalable or detailed. Scalable – not just on Friday afternoons

Tools you should be using 1) DICOM Radiation Dose SR (RDSR) - capturing procedure dose information 2) IHE Radiation Exposure Monitoring Profile (REM) - coordinating the capture and management of RDSR objects - applying in a radiology practice. 3) "CT dose screens" - porting legacy scanner data into RDSR 4) MITA CT Dose Check (XR-25) - pre-scan dose pop-ups on the CT console

5) IHE Integration Statements & DICOM Conformance Statements - specifying these standards & features when purchasing and integrating radiology systems.

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The Plumbing

Headers & Screen Shots

• Useful but limited – Missing details – Not machine-readable – Duplication issue – Size issue

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DICOM RDSR

Radiation Dose Structured Report

Object

DICOM 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) – PET/NM (NEW Final Text )

• Radiopharmaceutical Administration Radiation Dose Reporting

• Not addressed: RT

Key Measurements • CT Dose

– DLP, CTDIvol, kVP, mA, sec, … – Effective Dose [ Optional; Reference estimation method ] – SSDE (CP-1170) [ Optional; see AAPM 204 ]

• Projection X-Ray Dose – DAP, Dose@RP, kVP, mA, sec, … – Fluoro Dose, Fluoro Time – CR/DR: Exposure Index, Deviation Index

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

ftp://medical.nema.org/medical/dicom/2013/output/pdf/part16.pdf

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Mention WG-28 work to upgrade the pipeline to address organ dose, etc.

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

• Patient Size, Orientation, Anatomy Imaged • Imaging Geometry

• X-Ray Filtering & Collimation Details • Anode Target Material • Calibration, Phantom, Dosimeter, Patient Model

IHE REM Profile

Radiation Exposure Monitoring

some text: # Numerical Details 12.2 14.5 11.8 7.6 9.5 10.9









Numer 12.2 14.5 9.5 10.9

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Final Text in 2011, Folded into IHE Radiology Technical Framework in 2012 (Introduced in 2008, in recent years users have actually started asking for it.

IHE Radiation Exposure Monitoring Profile


National Registry

Archive Dose Information

Reporter

some text: # Numerical Details 12.2 14.5 11.8 7.6

Outlier: # Performing Phys. Over Target: 12.2%









Numer 12.2 14.5 9.5 10.9

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Final Text RDSR goes into the study record, onto CDs, etc. etc. Highlight that the Archive can be bypassed if need be, and that various innovative Dose Consumers can be incorporated And it’s a Pipeline. New fields will periodically be added to the RDSR, systems will start populating, and it all follows the same pipeline. (Spirit of not letting Perfect be the enemy of Good)

Legacy Dose Extractors

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Getting older systems into the same pipeline – do OCR and generate proxy RDSRs

Legacy Extractor • What if you can’t get REM? • Extractors create (partial) REM objects

– Based on OCR of dose screens – Based on image header contents – Based on MPPS

• Likely incomplete but still useful • Allows use of uniform infrastructure (RDSR) • Current focus: CT, some XA

Date

Patient ID DLP

CTDIvol

Patient Weight Scan Duration

SSDE

Filter

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Incomplete - likely to be missing patient weight, procedure details, fine grained information, phantom information, etc. etc.

Example Extractors • Open Source

– “Dose Utility” - dclunie.com • by David Clunie (PixelMed)

– “Radiance” - radiancedose.com • by Tessa Cook (Hospital of U of Pennsylvania)

– “GROK” – dose-grok.sourceforge.net • by Graham Warden (Brigham and Women's Hospital)

• Also – ACR Triad Site Server (included in ACR participation)

• by Mythreyi Chatfield (ACR)

– … and a growing number of commercial products

Protocol Managment

MITA XR-25 CT Dose Check

Dose Notification

Predicted DLP of 981 mGy-cm Exceeds Threshold …

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Going to Final Text in 2011

Dose Notification • Pop-up message

– Notifies technologist that dose for a current scan element will exceed a trigger value

– Tech may: • confirm and proceed, or • go back and adjust scan parameters

– System records audit trail • Predicted dose, Notification value, Date/time, diagnostic reason, etc.

• Clinical sites set values that will trigger a notification – Can set DLP and/or CTDIvol values for each scan element e.g. head without contrast – Defined by the clinical site for their patient population

Dose Alert • Pop-up message

– Alerts technologist cumulative dose for current study will exceed a trigger value: • CTDIvol (summed at each patient location) • DLP (summed over the current study)

– Tech may: • enter their name, (& a password if configured), confirm and proceed, or • go back and adjust scan parameters

• Clinical sites set values that will trigger an alert – Can set DLP and/or CTDIvol values

• System must allow at least one global value

– System tracks accumulated CTDIvol at each patient location & accumulated DLP – System checks predicted accumulated dose indices

when protocols are saved & when scans are ready to run

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Site can facilitate a variety of policies based on how they activate and distribute password.

Default Values • FDA has suggested an

alert value for CTDIvol of 1000 mGy

• AAPM notification value suggestions http://www.aapm.org/pubs/CTProtocols/

• Can be changed at local site

• Triggers vs. DRLs 75th percentile -> popups on 25% of scans

• Consider behavior modification vs. alert fatigue

ACR DIR

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Dose Index Registry

ACR Dose Index Registry nrdr.acr.org • Open to facilities worldwide • Anonymized data submission

– (via IHE REM or legacy extractor) • Provides periodic reports

– Dose statistics – Site Comparisons

• Modest annual participation fee

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Note: ACR was early collaborator for IHE REM profile

Takeaway Collect Your Data • New/recent Modalities

– IHE REM / DICOM RDSR to capture dose data • Legacy strategies

– Dose extractors to generate RDSR data

Analyze Your Data – IHE REM – Dose Information Reporter for local analysis – ACR Dose Registry to compare to benchmarks

Facilitate Prevention – CT Dose Check for configurable pre-scan alerts

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BUT this is not a radiation safety program in a box. These are tools. You need to understand the metrics for what they are (and aren’t), and implement a program to record/analyze/apply them sensibly

Finding Products • IHE REM

– Testing: IHE Connectathon http://connectathon-results.ihe.net – Product: IHE Integration Statement http://product-registry.ihe.net

• DICOM RDSR – Product: DICOM Conformance Statement

• NEMA XR-25 Dose Check

– Vendor commitment; most new products

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Ask for it • During RFPs / Purchase Requirements

– … shall support IHE REM as the Acquisition Modality actor … – Ask to see IHE Integration Statements & DICOM Conformance

Statements

• During Installation / Acceptance – Discuss activation / configuration

• During Upgrades

– Some models can be upgraded

radiation dose tracking standards structure tools …radiation dose monitoring: beyond ct (the...

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