THE DICOM V3.0 STANDARD
It's Working for Healthcare Worldwide
An important message from the ACR and NEMA Digital Imaging and
Communications Standards Committee
What is the DICOM Standard?
The Digital Imaging and Communications in Medicine (DICOM) Standard is a detailed
specification that describes the means of formatting and exchanging images and associated
information. The standard applies to the operation of the interface which is used to transfer data
in and out of an imaging device.
DICOM relies on computer industry standard network connections and addresses more
effectively the communication of digital images from diagnostic modalities beyond CT and MR
including nuclear medicine and ultrasound (contributions from corresponding NEMA sections),
and also computed radiography, digitized film, video capture and HIS/RIS information. It also
supports the connection of networked hardcopy devices.
DICOM is the result of an alliance of potential users of the standard (members of the American
College of Radiology - ACR) with the companies that manufacture medical equipment (members
of the National Electrical Manufacturers Association - NEMA) that began in 1984. DICOM has
also been embraced by other worldwide standards organizations and other healthcare disciplines
outside of radiology. These additional inputs to the DICOM effort have made extensive
contributions to its success.
The DICOM standard has now been implemented in an increasing number of medical products
of various vendors. The rapid adoption of DICOM by the medical imaging industry is opening
new opportunities for health care organizations to increase the quality of patient care and cost
effectiveness of the handling of and access to images and associated information.
Why do we need a standard interface?
A means is needed to get digital image data and associated information into and out of imaging
equipment, whether it be an acquisition system, an archiving system, a display workstation, or a
hardcopy device. Without an industry standard, custom interfaces are needed for each imaging
device. Currently, in a typical, multi-vendor imaging department, there is little compatibility of
equipment, so custom interfaces are developed or purchased in order to interconnect the
equipment. When DICOM is built into a medical imaging device, it can be directly connected to
What does a manufacturer do with the DICOM Standard?
A manufacturer uses the standard to design and build a product. The DICOM Standard describes
all of the detailed functional specifications which a device with a communications interface
(allowing one computer to "talk" to another computer) must employ to meet the standard. The
standard provides a common reference for all developers yet does not impose a single
implementation, thus allowing for innovation.
Some implementations of DICOM may still require the purchase and installation of a circuit
board and software for the imaging equipment. This approach is analogous to a cable television
converter which connects to the company cable on one side and provides standard video out on
the other for connection to a television set. An alternative is to integrate the DICOM interface
into the imaging equipment. This is analogous to a cable-ready TV receiver where no accessory
cable box is required as the circuitry necessary to do the translation from cable to video signals is
built into the TV.
In either case, the interface uses a set of computer software (programs) which operates in the
imaging equipment or accessory box (or both) and executes the DICOM protocol. The programs
also format the data for transmission. DICOM takes advantage of computer industry standards to
provide a network connection with other devices. This allows easy connection of DICOM
conformant imaging equipment to exist in hospital networks supported with off-the shelf
networking hardware and telecommunications services, and covering a broad range of
networking configurations. Intra-hospital connections, communications with remote clinics and
teleradiology applications are facilitated.
How can I use DICOM if I don't have a PACS?
DICOM is a valuable tool even if your department does not plan to install picture archiving and
communications system (PACS). In a multi-vendor environment, DICOM can be used to connect
specialized systems, such as 3-D image processing workstations, teleradiology systems, and
hardcopy devices. Introducing DICOM is often a simple task, and selecting DICOM
compatibility today will facilitate future PACS installation.
What is the current status of the DICOM Standard?
Approved in November 1993, the DICOM Standard is available as NEMA Standards
Publications PS 3.1 through 3.9. Key features of DICOM include:

The transfer of imaging studies from five modalities (CR, CT, MR, NM, US) as well as
Captured Images, Overlays and Lookup Tables.

The means to query for studies of patients and retrieve images as selected by the user.

The management of network connected hardcopy devices with basic film layout and
remote print job tracking.

The interchange of images on storage media such as CDs or optical disks.

The communication of patient and scheduling information, the management of imaging
studies, and exchange of results information, thus facilitating the integration of imaging
equipment with hospital and departmental information systems.

An effective framework for claiming conformance to DICOM which requires the
manufacturer of a product to specify explicitly in a DICOM Conformance Statement the
implemented functions of the Standard
Work continues on many useful supplements to DICOM which extends its usefulness to other
medical disciplines, such as Endoscopy, Radiation Therapy Planning and Pathology. Working
groups continue to be created by the ACR-NEMA committee (the joint committee formed by
ACR and NEMA in 1984 to develop digital imaging communication standards) at the request of
various interested parties to address extension of the standard in useful ways.
DICOM has made great strides since the initial demonstrations of basic capabilities at RSNA 92.
Since then, numerous demonstrations of DICOM have occurred at various international forums,
including SPIE, EuroPACS, CAR, JMCP, ECR, ACC, and every RSNA meeting since 1992.
DICOM products have been available from many manufacturers since RSNA 93. At RSNA 95,
over 40 vendors participated in the DICOM demonstration with their DICOM solutions.
The DICOM standard is internationally recognized for medical imaging. The European standards
body (Comite European de Normalisation) CEN TC 251 has adopted DICOM for the European
Standard MEDICOM. The Japanese Industrial Association of Radiation Apparatus (JIRA) has
based the new version of its MIPS standard on DICOM. ACR and NEMA participate in various
cooperative efforts, including the American National Standards Institute Healthcare Informatics
Standards Planning Panel, which coordinates the work of all the major healthcare standards
bodies in the United States, and provides formal liaison to standards organizations beyond the
USA.
Why the name DICOM?
Version 3.0 of the ACR-NEMA standard is called Digital Imaging and Communications in
Medicine or DICOM Standard to reflect the contribution of other international organizations as
well as the standard's ability, to expand beyond the sole support of radiology images. Examples
include the adoption of DICOM for images from cardiology, endoscopy, surgery and pathology.
DICOM embodies a number of key features:

The DICOM Standards has been carefully designed to facilitate its extension in a rapidly
changing health-care industry. This is reflected in its structure as a series of separate but
related parts as presented in Part 1 of DICOM.

The direct connection of medical equipment to standard TCP/IP network environments
without an intermediate network interface unit is specified in Part 8 of DICOM. This
brings a choice of cost effective and flexible network solutions (Ethernet, ISDN, ATM,
FDDI, Fast Ethernet, etc.).

Compatibility of conforming implementations is facilitated with the introduction of two
new concepts: services Classes and information Objects.. Service Classes define specific
operations (e.g. store, move, notification) across the network in a client/server mode.
Information Objects standardize the content of a wide range of image types (e.g. CT, MR,
NM, US, CR images) as well as related data (e.g. study management, results) from
hospital and departmental systems such as radiology information systems. These Service
Classes and Information Objects are addressed by Parts 3, 4, 5, 6, and 7 of the DICOM
Standard.

Part 2 of the DICOM Standard provides a structured approach to documenting
conformance to the standard. This is important to reduce ambiguities for the customer
who needs to integrate a multi-vendor network. It also allows the vendors to include, in
each product, features based on the applicable subset of the standard, a conformance
statement document is provided by the manufacturer.
Does DICOM address interchange of images on digital recording media?
Supplements to the DICOM standards for the exchange of images stored in digital form on
media such as optical disks were completed during 1995. The ACC actively participated in this
work, and there was extensive cooperation with JIRA and MEDIS-DC in Japan on this effort.
One of the first targeted applications is the exchange of x-ray angiographic studies on a
recordable compact disk (CD-R). A prototype demonstration of this capability occurred in March
1995 at the ACC meeting, and an additional demonstration is planned for March 1996.
Manufacturers have already announced products using these new DICOM supplements.
What has been demonstrated at RSNA in December?
One of the highlights of RSNA 95 has been the network connectivity demonstration of products
and prototypes based on DICOM across the commercial exhibits. Forty different companies have
participated in this demonstration and connected one or more of their imaging systems on the
RSNAnet and accessed the RSNA DICOM Servers. These servers were developed for RSNA by
the Mallinkrodt Institute for Radiology (Washington University, St. Louis, MO, USA).
This demonstration built upon the successful RSNA 1992 through 1994 demonstrations and
proved the expanding maturity of DICOM implementations.
Key features of the demonstration included:

Query and retrieve from the RSNA DICOM servers of a broad selection of high quality
test images, including MR, CT, ultrasound, nuclear medicine, digitized film, and
computed radiography images provided by several manufacturers.

Acquisition, storage, retrieve and printing of attendees pictographs to provide live
demonstrations.

Hardcopy filming devices have been shown connected through the RSNAnet to the
RSNA DICOM server from which print services were requested.

Patient and study management have been demonstrated through a work-list management
application on the RSNA DICOM server interacting with acquisition devices and thus
provided with HIS/RIS interfacing capability.

Access to results on workstations has also been demonstrated.
Where does DICOM go from here?
The DICOM standard has now been implemented in a large number of medical products of
various vendors and validation is on-going between vendors in order to verify proper
implementation of the standard. NEMA has formed the Committee for the Advancement of
DICOM to specifically promote and facilitate the use of the standard. One activity of the
committee is the development of a suggested Guideline for the testing of DICOM-equipped
products, which is to be publicly available in early 1996.
Because of the availability of DICOM in products, users are now realizing the real benefits of the
standard, which is INTER-OPERABILITY - the ability to provide applications and functionality
over a network. Now functionality that was only available within the constraints of products of a
single vendor, has been proven to exist in a multi-vendor environment. This was one of the main
objectives of the standard, but now radiologists and physicians are beginning to experience this
benefit.
Among users, an new question has arisen: "Now that I have DICOM, what can I do with it?"
Discussions have moved from "how" to "what". This new awareness with the users of medical
equipment is driving the development of products for new applications, beyond the traditional
methods of the past. This will result in improved efficiency of healthcare delivery.
This new awareness is facilitating better cooperation between competing suppliers of medical
equipment, since the users of equipment are now expecting interoperability in their new
equipment.
DICOM is a joint effort of users and manufacturers, and it's working!
Where can I find out more?
The DICOM Standard may be obtained be calling NEMA Customer Service at 703-841-3200.
At RSNA 95, information about DICOM was available from vendors taking part in the DICOM
Demonstration.
DICOM will also be discussed and demonstrated at several international meetings in 1996,
including SPIE, SCAR, CAR, ACC and RSNA 96.
Questions?
Ms. Vicki Schofield, Industry Manager, NEMA 1300 North 17th Street, Suite 1847, Rosslyn,
VA 22209, USA/ Phone: (703)841-3281; fax: (703)841-3381, vic_schofield@nema.org
Mr. David Snavely, Industry Manager, NEMA 1300 North 17th Street, Suite 1847, Rosslyn, VA
22209 USA/ Phone: (703)841-3285; fax: (703)841-3385, dav_snavely. nema.org
Mr. Jim Morison, Deputy Chief Operating Officer, American College Of Radiology, 1891
Preston White Dr. Reston, VA 22091, USA/Phone: (703)648-8900; fax: (703)648-3240,
jimm@acr.org.
Prepared by the ACR-NEMA Digital Imaging and Communications Standards Committee, with
support from the American College of Radiology and the MedPACS Section of NEMA whose
members are:

Acuson

Agfa

ATL

Camtronics Medical Systems

DeJarnette Research Systems

Digitec Corporation

DuPont De Nemours & Co.

Kodak Health Imaging Systems, Inc.

E for M Corporation

Eigen

GE Medical Systems

InfiMed, Inc.

Loral Medical Systems

Merge Technologies, Inc.

Nucletron-Oldelft

Phillps Medical Systems, North America

Picker International, Inc.

Polaroid Corporation

Siemens Medical Systems, Inc.

Sony Medical Systems

3M Medical Imaging Systems Division

TomTec Imaging Systems

Toshiba America Medical Systems