Picture archiving and communication system (PACS)

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Picture archiving and communication system (PACS) is a medical imaging technology which provides digital storage and electronic access to images from multiple modalities.

Traditionally PACS consists of four major components:

  • Imaging modalities (X-ray, MRI, CT, Ultrasound, etc)
  • Secured network for transmission
  • Viewer for interpreting and reviewing images
  • Archives for the storage and retrieval


The term PACS was first coined in 1982 at the First International Conference and Workshop on PACS held in Newport Beach, CA. Yet the basic idea of moving medical imagery over telephone lines dates back to 1929[2] and had been described several years prior to the conference[3]. The earliest PACS systems could be as simple as a film scanner and dial-up connection between two machines, and while second-generation systems in the latter-half of the 1980s placed more emphasis on the storage, retrieval and display features, were troublesome,[1] and still designed with a film-producing workflow in mind. The late 1980s saw an evolution in high-speed networks and imaging systems integration with ACR-NEMA (American College of Radiology-National Electrical Manufacturers’ Association) and later DICOM (Digital Imaging and Communication in Medicine) Standards.

In the early 1990s there was further integration of health information systems, radiology information systems and PACS. RIS provide information such as patient scheduling data, document management, billing and other adjunct information. Together, RIS and PACS are the two founding elements needed for a completely digital radiology department. For more information about RIS and PACS integration into other CIS systems, click here.


Originally, PACS was primarily utilized within radiology departments to manage the storage, retrieval, and review of various imaging modalities, including X-rays, CT scans, MRIs, and ultrasounds. However, its application has broadened to encompass additional medical fields such as ophthalmology, pathology, cardiology, oncology, and dermatology. The diverse imaging needs across these specialties often necessitate specialized PACS viewers. For instance, ophthalmologists need to analyze multiple image types—such as OCT Macula, Corneal Topography, IOL Calculations, OCT Retinal Nerve Fiber Layer, Humphrey Visual Fields, Fluorescein Angiograms, and Indocyanine Green Angiography—that are not supported by standard radiology-focused PACS viewers. This diversity underscores the importance of adopting a vendor-neutral archive in multi-specialty practices to accommodate the specific viewing requirements of different medical subspecialties.


The architecture of a Picture Archiving and Communication System (PACS) is dynamic, with varied configurations across different institutions. In a typical PACS workflow, four main components interact:

  • Worklist: A sophisticated tool that aggregates examination lists from various sources—be it different PACS, hospitals, or other healthcare entities. It integrates with diverse systems such as radiology information systems, PACS itself, or external applications. Worklists can draw from electronic medical records to enhance clinical data access.
  • Archive: A central archive stores images, reports, metadata and measurements. There has been a shift towards vendor-neutral archives that can connect with any PACS with standard communication protocols. This allows for interoperability across different PACS and allows the inclusion of medical images from non-radiology specialties (cardiology, ophthalmology, etc) that certain PACS vendors might not support.
  • Viewer: Essential for clinicians to review and interpret diagnostic images. The trend has moved from exclusive PACS workstations to more versatile, web-based viewers, expanding access options to include remote and mobile platforms. Although third-party and web viewers offer increased accessibility, they may lack some of the sophisticated visualization capabilities of dedicated radiology workstations.


Picture Archiving and Communication Systems (PACS) offer several benefits:

  • Digital storage: Eliminates the need for physical film and storage. Less need for space and expenses associated with film processing and storage. It also enables faster access and transfer of medical images.
  • Remote access: Images stored in PACS can be accessed by multiple users from multiple locations and allows for teleradiology.
  • Integration with RIS/HIS: Allows for easier transfer of imaging and clinical information across departments.
  • Digital format: Allows for digital formats that can be manipulated to enhance diagnostic accuracy.

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PACS - Next Generation


  1. Sending dental x-rays by telegraph Anonymous, Dent Radiog Photog 2 (1929) (1), pp. 1–2.
  2. Lemke, HU (1979) A Network of Medical Work Stations for Integrated Word and Picture Communication in Clinical Medicine, Technical Report., Technical University, Berlin
  3. Siegel E, Reiner B. Work Flow Redesign : The Key to Success When Using PACS [Internet]. AJR. American journal of roentgenology. 2002 ;178(3):563-6. Available # from: http://www.ajronline.org/cgi/content/abstract/178/3/563
  4. Huang HK. Short history of PACS. Part I: USA. Eur J Radiol. 2011;78(2):163-176. doi:10.1016/j.ejrad.2010.05.007
  5. Berkowitz SJ, Wei JL, Halabi S. Migrating to the Modern PACS: Challenges and Opportunities. Radiographics. 2018;38(6):1761-1772. doi:10.1148/rg.2018180161

Submitted by Niranjan Manoharan