Digital Imaging and Communications in Medicine (DICOM)



Description


DICOM or Digital Imaging and Communications in Medicine is a standard that is used in medical imaging. It is designed to ensure the interoperability of various systems by standardizing the way digital imaging is stored, printed, handled and transmitted. The DICOM standard was first developed in 1985 by the American College of Radiation (ACR) and the National Electronics Manufacturers Association (NEMA). Combined, these two developed the first version of DICOM, which at the time was called ACR/NEMA 300. In 1992, during the development of the third version, the standard was given the name DICOM. It is now a product of the DICOM Standards Committee, which consists of user organizations such as professional societies, producers or companies that develop imaging technologies, and general interest members such as government agencies.

The current version of DICOM consists of nine parts (with several more parts on the way for the next version). Part One gives an overview of the standard. Part Two defines the conformance to the DICOM and what it means to conform to the standards. Part Three defines the objects in the DICOM and their attributes.There are many other parts that contain things such as specifications of the various services, defining media exchange standards, and standards for file formats.

As defined in Part Three, a DICOM data object is grouped into data sets which are collections information from various parts of the DICOM. Each object has a number of attributes including: name, ID, etc, and then one called pixel data, or the attribute for the image file. There can only be one image file per object, however there are image files that allow frames and looping to allow for multiple images. DICOM tries to maintain a variety of technology standards such as JPEG (for images), MPEG (for video), TCP/IP (for connecting the networks), and others such as SNOWMED. DICOM has worked with the International Organization for Standardization (ISO) to develop a new standard for web access to DICOM objects. DICOM is also part of the Integrating the Healthcare Enterprise (IHE) initiative which sets out to help bother users and vendors determine sound ways to implement the medical imaging systems. DICOM has also formed a group with the Health Level 7 (HL7) to develop standards amongst the two groups. To maintain the ever changing standards of technology, there are many work groups involved with DICOM that work to update the DICOM four to five times a year, with a new publication every one to two years.

Part Four of the DICOM consists of the description of many of the different services. Some of the services include the following:

  • Store - This service stores the image file and then sends it to a Picture Archiving and Communication System (PACS) workstation.
  • Print - The print service allows the image file to be sent to a DICOM printer, where X-ray film is printed. This service follows a standard as well and tries to keep consistency between the different displays and printing devices
  • Retrieve - This is a simply querying service that allows you to access and retrieve information from the PACS.
  • Modality Worklist - Allows the imaging system to pull patient information or appointments that have already been entered into another system, avoiding the need for re-entering that information.
  • Off-line Media - A service that prepares the medical imaging information for removable storage.


Applications


The DICOM has a variety of important applications. DICOM is used in hospitals, clinics, dentist's offices and other healthcare areas across the globe. By purchasing systems that conform to the DICOM standards, you ensure that this equipment will work regardless of what vendors you use.The manufacturers of imaging equipment such as scanners, printers, monitors, etc, build their products with the DICOM standards in mind to ensure that their equipment will work with any vendor or workflow (such as electronic health record (EHR) systems.)

There are many imaging services, surgeries and other medical procedures that use the DICOM. The DICOM is used in very common procedures such as Computed Tomography (CT or CAT scan), Mammography, Ultrasound, magnetic resonance imaging (MRI), Positron Emission Tomography (PET scan), and many others. DICOM is used a variety of specialist areas such Cardiology, Neurology, Oncology, Dentistry, Pathology, and is used by Veterinarians. Some other imaging procedures that use the DICOM are:


Graphics


dicom_intro2.gif
The DICOM Application Model

dicom3.0.jpg
A diagram showing a variety of equipment using the DICOM.

sampleDICOM.jpg
An example of imaging software that uses the DICOM standard



Web Resources



Related Terminology


Interoperability - The ability of software and hardware on different machines from different vendors to share data.

Modality - In medical imaging, any of the various types of equipment or probes used to acquire images of the body, such as radiography, ultrasound and magnetic resonance imaging.

Electronic Health Record - A medical record or any other information relating to the past, present or future physical and mental health, or condition of a patient which resides in computers which capture, transmit, receive, store, retrieve, link, and manipulate multimedia data for the primary purpose of providing health care and health-related services.

Attribute - In database management systems, the term attribute is sometimes used as a synonym for field.

Information Object Definitions (IOD) - Provide an abstract definition of real-world objects applicable to communication of digital medical information.


Citations/References


http://medical.nema.org/dicom/geninfo/Brochure.pdf (Opens in a .PDF)
http://en.wikipedia.org/wiki/DICOM
http://www.dicomanalyser.co.uk/html/introduction.ht