Dosis “Data Mining”

Paul W. de Bruin

klinisch fysicus radiologie i.o.Afdeling Radiologie

Leids Universitair Medisch Centrum

The Ideal World

1. Dose data is available at the scanner after a scan2. Dose data is stored in an archive

3. Statistics on dose data can be calculated (“data mining”)

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Californian Senate Bill no. 1237

• 115111. (a) Commencing July 1, 2012, subject to subdivision (e), a person that usesa computed tomography (CT) X-ray system for human use shall record the dose ofradiation on every CT study produced during a CT examination.

• (b) The facility conducting the study shall electronically send each CT study andprotocol page that lists the technical factors and dose of radiation to the electronicpicture archiving and communications system.

• (c) The displayed dose shall be verified annually by a medical physicist to ensure thedisplayed doses are within 20 percent of the true measured dose measured inaccordance with subdivision (f) unless the facility is accredited.

• (d) Subject to subdivision(e), the radiology report of a CTstudy shall include the doseof radiation by either recording the dose within the patient’s radiology report orattaching the protocol page that includes the dose of radiation to the radiology report.

• (e) The requirements of this section shall be limited to CT systems capable ofcalculating and displaying the dose.

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DICOM/RIS/PACS/ZIS/EPD?

• DICOM: Digital Imaging and Communications in Medicine• http://medical.nema.org

• Data structures (patients, images, reports)

• Services (storage, query, retrieval, transfer of data)

• PACS: Picture Archiving and Communication System• Data archive

• IHE: Integrating the Healthcare Enterprise• Workflow definition for modalities and PACS

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Example Dicom - I

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Example Dicom - II

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Example Dicom - III

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Dosis

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How to get dose information

• Basic DICOM• DICOM SR (Structured Report)

• Dose reports stored as “screen saves”

• Use DICOM MPPS

• Query PACS

• IHE REM: defines workflow

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DICOM Structured Report

• DICOM Class• A “databaseable document” format linked with image data

• computer search analysis• research

• education

• clinical trials

• data mining

• Templates Working Groups• DICOM Dose SR

• Supplement 127: CT Radiation Dose Reporting (Dose SR)

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DICOM Structured Report – example text dump

(0008,0100) SH [CODE_12] # 8, 1 CodeValue

(0008,0102) SH [99_OFFIS_DCMTK] # 14, 1 CodingSchemeDesignator

(0008,0104) LO [Illnesses] # 10, 1 CodeMeaning(fffe,e00d) na (ItemDelimitationItem) # 0, 0 ItemDelimitationItem

(fffe,e0dd) na (SequenceDelimitationItem) # 0, 0 SequenceDelimitationItem

(0040,a160) UT [The patient had polio at age 8, from which she made a remarkable r... # 206, 1 TextValue

(fffe,e00d) na (ItemDelimitationItem) # 0, 0 ItemDelimitationItem

(fffe,e000) na (Item with undefined length #=4) # u/l, 1 Item

(0040,a010) CS [CONTAINS] # 8, 1 RelationshipType

(0040,a040) CS [TEXT] # 4, 1 ValueType(0040,a043) SQ (Sequence with undefined length #=1) # u/l, 1 ConceptNameCodeSequence

(fffe,e000) na (Item with undefined length #=3) # u/l, 1 Item

(0008,0100) SH [CODE_13] # 8, 1 CodeValue

(0008,0102) SH [99_OFFIS_DCMTK] # 14, 1 CodingSchemeDesignator

(0008,0104) LO [Allergies] # 10, 1 CodeMeaning

(fffe,e00d) na (ItemDelimitationItem) # 0, 0 ItemDelimitationItem

(fffe,e0dd) na (SequenceDelimitationItem) # 0, 0 SequenceDelimitationItem(0040,a160) UT [ALLERGIC TO PENICILLIN. She denies any other drug or food allergies.] # 68, 1 TextValue

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DICOM Structured Report - Example

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“The finding is a massmeasuring 1.3 cm indiameter with an infiltrativemargination.The conclusion is aprobable malignancy,inferred from the infiltrativemargination of the mass.”

Hussein et al. DICOM structured reporting: Part 1. Overview and characteristics. Radiographics : a review publication of the Radiological Society of North America, Inc (2004) vol. 24 (3) pp. 891-6

David A. Clunie, DICOM Structured Reporting, ISBN 0-9701369-0-0, out of print. PDF at: http://www.pixelmed.com/srbook.html

Dosis Report – Screen Shot - EVAR

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Dose Report – Screen Shot - 1

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Dose Report – Screen Shot – 2

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Dose Utility – David Clunie

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http://www.dclunie.com/pixelmed/software/webstart/DoseUtilityUsage.html

DICOM Modality Performed Procedure Step

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Bron: Brain Sanderse, ICT Architect, Amphia Ziekenhuis

Commercieel beschikbaar (http://www.krucom.com)

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Query the PACS

1. Via vendor interface

2. Using the DICOM interface

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DICOM Patient-Study-Series-Image Model

ImageSeriesStudyPatient

Jansen CT Onderzoek ScoutPALR

Anatomische scan Image 1

Image …

Image 200

Contrast

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Image 1

Image …

Image 600

Work flow

• Query PACS for studies on a date• For each study query PACS for

series (filter on CT/DX/MAMMO)

• For each series query PACS forimages

• Retrieve each image• Throw away image data

• Store dose information in localdatabase

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Why so complicated?

• Patient-Study-Series-Image is dictated by DICOM• Attributes are defined at different levels:

• Modality is defined at Series level.

• Dose information is defined at Image level.

• No support for optimized generic batch retrieval.

• PACS has limit on number of query results

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CT Dose from DICOM Images

García et al. Automated effective dose estimation in CT. Radiat Prot Dosimetry (2010) vol. 138 (1) pp. 71-7

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CT Dose from DICOM Images

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Dose monitoring is a hot topic

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Concluding

Storage•Basic DICOM

• Standard dose parameters• Basic modality support

•DICOM SR (Structured Report)• Not implemented (yet) by most vendors• “Best solution”

•Dose reports stored as “screen saves”• Better than nothing or manual lists• Implemented by most vendors• Can be converted to DICOM SR

•DICOM MPPS• Dose information via messages,

messages are not stored• Cannot go back in PACS history• Commercial third-party solution

available•Generic

• History?

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Data Mining/Retrieval•Query PACS

• Using PACS functionality provided byvendor

• rare

• Using DICOM interface

• Generic

• Brute-force

• Slow

• Generic

• Can only retrieve what is in thePACS