ACR-NEMA

• 1982 - ACR and NEMA form a joint committee• 1985 - Publication of Version 1.0• 1988 - Compression and Mag Tape Standards• 1988 - Publication of Version 2.0 • 1989 - Began work on Network Version with

HIS/RIS

First meeting organized by ACR and NEMA in 1983

DICOM

• The name was changed to separate the standard from the originating body

• 1991 - Release of Parts 1 and 8 of DICOM• 1992 - RSNA demonstration, Part 8• 1993 - DICOM Parts 1-9 approved,

RSNA demonstration of ALL parts• 1994 - Part 10: Media Storage and File Format• 1995 - Parts 11,12, and 13 plus Supplements

First successful DICOM Standard issued in 1993

Scope of DICOM• To create & maintain international standards for communication of

biomedical diagnostic and therapeutic information in disciplines that use

digital images & associated data

• To achieve compatibility & to improve workflow efficiency between imaging

systems & other information systems in healthcare environments worldwide.

• DICOM is a cooperative standard

• Every major diagnostic medical imaging vendor in the world has

incorporated the standard into their product design

• Most of the professional societies throughout the world have supported &

are participating in the enhancement of the standard as well

DICOM is the ONLY standard in the world that covers the exchange of medical images

The DICOM Standards Committee & Working Groups

WG1: Cardiac and Vascular Information

WG12: Ultrasound

WG2: Digital X-Ray WG13: Visible Light

WG3: Nuclear Medicine WG14: Security

WG4: Compression WG15: Digital Mammography

WG5: Exchange Media WG16: Magnetic Resonance

WG6: Base Standard WG17: 3D

WG7: Radiotherapy WG18: Clinical Trials and Education

WG8: Structured Reporting WG19: Dermatologic Standards

WG9: Ophthalmology WG20: Integration of Imaging and Information Systems

WG10: Strategic Advisory WG21: Computed Tomography

WG11: Display Function Standard WG-22: Dentistry

WG-23: Application Hosting

Communication Standards• Protocols are defined by standards• A Standard is an agreement which may be voluntary,

Government mandated, or International Law • Protocols may also be proprietary

Who Defines Communication Standards?• User Consortia (e.g., HL7)• Organizations (e.g., NEMA, IEEE)• US Government Agencies (e.g., ANSI, NIST)• Foreign Government Agencies (e.g., CEN)• United Nations (e.g., ISO, CCITT)

ISO Reference Model

LLCMAC

PHYSICAL

DATA LINK

NETWORK

TRANSPORT

SESSION

PRESENTATION

APPLICATION

Fiber, Coax, UTP, µWave

End-to-End communication

Data Formatting, Compression,Encryption

File Transfer, E-mail, HTTP

Ethernet, FDDI, etc.

Internetworking

Upper Layers(DICOM)

Synchronization,Comm. Management

Lower Layers

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

More than 100 supplements (extensions) to the Standard provide additional capabilities

• 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)

Technology OverviewAt the application layer, the services and information objects address

five primary areas of functionality:• Transmission and persistence of complete objects (such as images, waveforms and

documents)

• Query and retrieval of such objects

• Performance of specific actions (such as printing images on film)

• Workflow management (support of worklists and status information)

• Quality and consistency of image appearance (both for display and print)

DICOM Fundamentals• OBJECT DATA MODEL

– DICOM is based on a completely specified data model

– DICOM includes a robust UID mechanism

• DATA DICTIONARY– DICOM includes a large number of new

data elements

• SERVICE CLASSES– DICOM defines classes of service for

specific applications (e.g. image management, printing) and conformance levels

DICOM Terminology

• DICOM Message Service Element (DIMSE) - The set of DICOM Application Layer communication services.

• DIMSE Service Group (DSG) - A subset of the full DIMSE services which is applicable to a specific IOD.

• Information Object Definition (IOD) - A data abstraction of a class of real-world objects. A collection of related attributes (data elements).

DICOM Terminology

• Service Class - A set of functionality relating to a single type or real-world activity. Composed of a set of SOP Classes plus rules and associated semantics.

• Service-Object-Pair Class (SOP) - The atomic unit of DICOM functionality. Composed of an IOD and a DIMSE Service Group plus restrictions or extensions of the IOD. (Equivalent to an Object Class)

DICOM Service Classes

• Composite– Verification– Storage– Query/Retrieve– Study Content Notification

• Normalized– Patient Management– Study Management– Results Management– Basic Print Management

DICOM Data TypesValue Representation

Description

AE Application Entity

AS Age String

AT Attribute Tag

CS Code String

DA Date

DS Decimal String

DT Date/Time

FLFloating Point Single (4 bytes)

FDFloating Point Double (8 bytes)

IS Integer String

LO Long String

LT Long Text

OB Other Byte

Value Representation

Description

OF Other Float

OW Other Word

PN Person Name

SH Short String

SL Signed Long

SQ Sequence of Items

SS Signed Short

ST Short Text

TM Time

UI Unique Identifier

UL Unsigned Long

UN Unknown

US Unsigned Short

UT Unlimited Text

DICOM Attribute Encoding