Digital Imaging and COmmunication in Medicine (DICOM) ผศ. รุจชัย อึ้งอารุณยะวี ภาควิชาวิศวกรรมคอมพิวเตอร์ คณะวิศวกรรมศาสตร์ มหาวิทยาลัยขอนแก่น

Picture Archive and Communication System: PACS Based on DICOM

The Parts of the DICOM Standard Part 1 - Introduction and Overview Part 2 - Conformance Part 3 - Information Object Definitions Part 4 - Service Class Definitions Part 5 - Data Structures & Semantics Part 6 - Data Element Listing and Typing Part 7 - Message Exchange Protocol Part 8 - Network Support for Message Exchange Part 9 – Point to Point Part 10: Media Storage and File Format for Media Interchange Part 11: Media Storage Application Profiles Part 12: Media Formats and Physical Media for Media Interchange Part 14: Grayscale Standard Display Function Part 15: Security and System Management Profiles Part 16: Content Mapping Resource Part 17: Explanatory Information Part 18: Web Access to DICOM Persistent Objects (WADO) More than 100 supplements (extensions) to the Standard provide additional capabilities DICOM 3.0DICOM 2007

DICOM History ► Based on ACR-NEMA standard ▪ ACR (American college of radiology) ▪ NEMA (National Electrical Manufacturers Association) ACR and NEMA form a joint committee Publication of Version Compression and Mag Tape Standards Publication of Version Began work on Network Version with HIS/RIS

DICOM History (cont.) The name was changed to separate the standard from the originating body Release of Parts 1 and 8 of DICOM RSNA demonstration, Part DICOM Parts 1-9 approved, RSNA demonstration of ALL parts Part 10: Media Storage and File Format Parts 11,12, and 13 plus Supplements First successful DICOM Standard issued in 1993 DICOM is the ONLY standard in the world that covers the exchange of medical images

The DICOM File Format ► Header containing ▪ the patient's name / id ▪ type of media (CT, MRI, audio recording, etc.) ▪ image dimensions ▪... ► Body, containing «information objects» ▪ medical reports ▪ audio recordings ▪ images

A Typical DICOM Image File

DICOM Value Representations (VR) All DICOM attributes are formatted according to 27 value representation (VR) types

Value Representation Description AEApplication Entity ASAge String ATAttribute Tag CSCode String DADate DSDecimal String DTDate/Time FLFloating Point Single (4 bytes) FD Floating Point Double (8 bytes) ISInteger String LOLong String LTLong Text OBOther Byte Value Representation Description OFOther Float OWOther Word PNPerson Name SHShort String SLSigned Long SQSequence of Items SSSigned Short STShort Text TMTime UIUnique Identifier ULUnsigned Long UNUnknown USUnsigned Short UTUnlimited Text

DICOM Services DICOM data attributes can be transmitted and processed between various DICOM devices and software (Applications) DICOM applications provide services to each other Particular services always associate with the data (IODs) that they process. These associations are called Service-Object Pairs (SOPs)

Example: CT Storage SOP CT image = DICOM IOD (DICOM data object). CT Storage = DICOM Service CT Scanner = SCU (Service Class User) Digital Archive = SCP (Service Class Provider)

Data Communication Information about each device is called Presentation Context. Data transfer begins with Handshaking on the presentation context. If the two applications can match their contexts, they can connect and start SCU-SCP processing.

DICOM Conformance Statement Each DICOM unit will be accompanied by its own DICOM Conformance Statement from the manufacturer This statement explains which SOPs (services) the unit supports, and to what extent (SCU, SCP, or both) For example, if you buy a digital archive that supports only CT Storage SCU (does not support CT Storage SCP) you won’t be able to store CT images in it. The archive won’t be able to provide the CT storage service.

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