• RadLex

  • What is RadLex?

    As images, imaging reports and medical records move online, radiologists need a unified language to organize and retrieve them. Radiologists currently use a variety of terminologies and standards, but no single lexicon serves all of their needs.

    Enter RadLex, a comprehensive lexicon—a unified language of radiology terms—for standardized indexing and retrieval of radiology information resources. With more than 68,000 terms, RadLex satisfies the needs of software developers, system vendors and radiology users by adopting the best features of existing terminology systems while producing new terms to fill critical gaps. RadLex also provides a comprehensive and technology-friendly replacement for the ACR Index for Radiological Diagnoses. It unifies and supplements other lexicons and standards, such as SNOMED-CT and DICOM.

    RSNA has developed a term browser (radlex.org) to give potential users a convenient way to view RadLex's structure and content. RadLex is available for download via the National Center for Biomedical Computing’s Bioportal.


    In 2005, RSNA formed six RadLex organ system committees. Representatives of more than 30 radiology professional and standards organizations, including the American College of Radiology (ACR), DICOM, and IHE, participated in the process. In November 2006, they publicly released an initial set of more than 7,500 anatomic and pathologic terms.

    Six additional committees, each focusing on a specific imaging modality, were recruited in 2007 to develop the RadLex Playbook which encompasses terms to describe the devices, imaging exams, and procedure steps performed in radiology. Playbook terms have been incorporated in the current release of RadLex. Beginning in 2008, RSNA contracted with Northwestern University on a related effort to create a standardized "chargemaster" of radiology orderables and procedure steps.

    RadLex development is supported both by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and by the cancer Biomedical Informatics Grid (caBIG) project, a large NIH-sponsored effort to develop unified computing infrastructure for clinical trials.

  • Resources

  • RsnaProgram7

    Bioportal Download  

    Download the latest RadLex ontology and review additional details, metrics, versions and projects that use RadLex.


    Developers’ Wiki 

    Access information for users, term and program developers, the community portal, current events and recent changes.


    RadLex Ontology License  

    This License permits public access to the Release Version of RadLex® and to use it without charge.


    Release Notes  

    Stay up to date on the latest additions and amendments to RadLex terms, preferred names and synonyms.

We appreciate your comments and suggestions in our effort to improve your RSNA web experience.

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