Transcript DICOM Digital Imaging COmmunications in Medicine

DICOM
Digital
Imaging COmmunications in
Medicine
Cary Education Seminar
March 9, 1995
Clinical Networking
Communication Protocols:
Key to Connectivity
 Layered Model, each layer performs a specific function
 Set of Services and Protocols
 Connectivity requires sharing a complete protocol
 Communication requires a shared Semantic Context
Cary Education Seminar
March 9, 1995
Clinical Networking
ISO Reference Model
APPLICATION
Protocol Converter s
Cary Education Seminar
March 9, 1995
File Transfer, E-mail, VT, DIR
PRESENTATION
Data Formatting
SESSION
Synchronization
TRANSPOR T
End-to-End communication
Routers
NETW ORK
Internetworking
Bridges
DATA LINK
LLC
MAC
Repeaters
PHYSICAL
Ethernet, FDDI, etc.
Fiber, Coax, UTP, µWave
Clinical Networking
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
Cary Education Seminar
March 9, 1995
Clinical Networking
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)
Cary Education Seminar
March 9, 1995
Clinical Networking
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
Cary Education Seminar
March 9, 1995
Clinical Networking
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
Cary Education Seminar
March 9, 1995
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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 Support
Cary Education Seminar
March 9, 1995
Clinical Networking
The Parts of the DICOM Standard
 Part 10 - Media Storage and File Format
 Part 11 - Media Storage Application Profiles
 Part 12 - Media Formats and Physical Media
 Part 13 - Print Management Point-to-Point
Cary Education Seminar
March 9, 1995
Clinical Networking
DICOM Application Domain
Storage, Query/Retrieve,
Study Component
LiteBox
MAGN
ETOM
Print Management
Query/Retrieve
Results Management
Media Exchange
Query/Retrieve, Patient & Study Management
Information Management System
Cary Education Seminar
March 9, 1995
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Summary of DICOM Features
 NETWORK PROTOCOL
DICOM incorporates negotiation to permit nodes to agree on
the functions to be performed
 MESSAGE ENCODING
DICOM defines 24 data types (V2.0 had 4)
DICOM message encoding includes JPEG compression (17
varients)
DICOM includes encapsulated image and multi-frame syntaxes
DICOM supports multiple character repertoires
Cary Education Seminar
March 9, 1995
Clinical Networking
Summary of DICOM Features
 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
Cary Education Seminar
March 9, 1995
Clinical Networking
Summary of DICOM Features
 Off-Line Media Support
DICOM defines a directory structure and media profiles
 CONFORMANCE
DICOM requires conformance statements and contains detailed
conformance requirements
Cary Education Seminar
March 9, 1995
Clinical Networking
Network Protocol
Medical Imaging Application
DICOM Application Entity
ISO Upper
Layer Service
boundary
Session /
Transport /
Network
(STN)
Data Link
Cary Education Seminar
March 9, 1995
DICOM
Upper layer
protocol
for TCP/IP
ISO Association Control
Service Element (ACSE)
ISO PRESENTATION
ISO SESSION KERNEL
TCP
IP
ISO TRANSPORT
ISO NETWORK
LLC
Physical
(50-pin)
Ethernet, FDDI, ISDN, etc.
Point-to-point
Network Environment
Clinical Networking
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).
Cary Education Seminar
March 9, 1995
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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)
Cary Education Seminar
March 9, 1995
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Service-Object Pair Class
Data Dictionary
Information Object
DIMSE Service Group
SOP
Real-World Object
Cary Education Seminar
March 9, 1995
Clinical Networking
DICOM Service Classes
 Composite
Verification
Storage
Query/Retrieve
Study Content Notification
 Normalized
Patient Management
Study Management
Results Management
Basic Print Management
Cary Education Seminar
March 9, 1995
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Conformance
 DICOM Part 2 specifies the structure of a
conformance statement
 DICOM does not specify a test suite or a
compliance verification mechanism
 All DICOM implementations must be supported by
a properly constructed conformance statement
Cary Education Seminar
March 9, 1995
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DICOM Conformance Statement
 Implementation Model which describes the
Application Entities in the implementation
 Detailed specification of each Application Entity
SOP Classes supported
policies for initiation and acceptance of associations
 Presentation Contexts
 SOP options
 Supported communications protocols
 Specializations
 Configuration
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Purpose of a Conformance
Statement
 Allow a user to determine which optional
components of the DICOM Standard are
supported by a particular implementation, and
what extensions or specializations an
implementation adds.
 By comparing the Conformance Statements from
two implementations, a knowledgeable user
should be able to determine whether or not
interoperability is possible.
Cary Education Seminar
March 9, 1995
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DICOM Conformance Testing
 No Formal Mechanism is Defined in the Standard
 Committee for the Advancement of DICOM
 Define initial test plan and cross-connect matrix
 Future RFP for organization to monitor the process
 Problem: How to Map DICOM Conformance
Statements into Test Plans
Cary Education Seminar
March 9, 1995
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The DICOM Explosion
 Joint CEN-DICOM development
 Medicom = DICOM
 MIPS 95 work is underway with JIRA
 IS&C Harmonization is also in progress
 HL7 Harmonization continuing interest
 New DICOM organization
Companies: NEMA and non-NEMA
ACR, ACC, CAP, ...
individuals
Cary Education Seminar
March 9, 1995
Clinical Networking
Summary
 Networking is a critical component of all medical
imaging systems
 Support for Open Communication Standards is a
MUST
 DICOM is here, NOW
 DICOM products exist on the market
 DICOM is emerging as THE common protocol for
medical image communication - WORLD WIDE!
Cary Education Seminar
March 9, 1995
Clinical Networking