DRG Requirements Specification for Media Containing Patient Information

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DRG Requirements Specification for Media Containing Patient Information

Radiological images are increasingly exchanged in digital form using storage media, so-called "patient CDs/DVDs". So far, there are no requirements regarding the structure of such CDs, so that a multitude of CD format variants can be found on the market. For this reason, it often comes to problems since the receiver of a patient CD may not always be able to visualize or process the CD content. Therefore, the German Society of Radiology and OFFIS have developed a Requirements Specification for patient CDs, based on the "Portable Data for Imaging" (PDI) specification of the IHE initiative. The Requirements Specification thoroughly specifies the internal structure of media containing radiological images to be valid in terms of the DRG Media Exchange Project. The Requirements Specification contains technical rules, e. g. which media types and file systems are permitted, as well as some rules defining the format of the medical content stored on a patient CD.

The complete Requirements Specification can be downloaded here (PDF format):

PDF-Logo Requirements Specification for Exchange Media Containing Patient Information
Edition 2006 (as of 2006-10-27)
PDF-Logo German Version:
DRG-Anforderungskatalog für Datenträger mit Patienteninformationen

Ausgabe 2006 (Fassung vom 27.10.2006)
If you are interested in an overview of the media specification, you can read the following short summary.

General Requirements

The DRG Requirements Specification only permits CDs as valid medium, with support for DVD planned for a future version of the specification. In both cases, a file system according to ISO 9660 is required on the medium with possible extensions like Joliet, Rockridge or Multisession explicitly allowed. Furthermore, it is recommended not to use any autostart feature on the medium and to perform a virus check at the end of CD creation.

The CD must be labeled with human readable information. It is recommended to label the medium with name and birth date of the patient, the patient ID, date of media creation, date information about the studies on the medium and the name of the institution where the medium was created. In addition, it is recommended to provide information about the kind of content on the medium.

DICOM Content

It is recommended to store all information that is relevant for the current clinical condition of the patient(s) (including reports, discharge letters etc.) in DICOM format on the medium. For that purpose, the ability of the DICOM standard to encapsulate PDF documents into DICOM objects can be used. The DICOMDIR file in the root directory of the medium serves as an entry point to all DICOM data on the CD and references all other DICOM files on the medium. Regarding the DICOM files and especially regarding the DICOMDIR, there are some additional restrictions in the DRG media specification. All DICOM files on the medium also must comply to the rules imposed by the DICOM standard.

The content on a CD may belong to one or more patients. The transfer syntax (i. e., also a possible compression) and the types of objects on CD are restricted by some of the DICOM application profiles listed in the media specification.

Web Content

In addition to the DICOM content, media may also contain Web Content. If Web Content is included on the medium, it must be derived from the DICOM content found on the same medium. The derived Web Content must either reflect the complete DICOM content on the medium or only that part of the DICOM content that truthfully reflects the clinical condition of the patient at the time of medium creation.

As an entry point, a file named INDEX.HTM is used that must be placed in the root directory of the medium. All Web Content (except INDEX.HTM) must be placed in a single, separate directory located in the root directory of the medium. All files of the Web Content must be referenced (directly or indirectly) from the INDEX.HTM file. Additionally, all DICOM Content and Other Content on the medium must be listed in the INDEX.HTM file. The Web Content files itself must be in XHTML format with additional JavaScript explicitly allowed. The use of other scripting languages is not permitted. The format of possible image and video data is also restricted in the Web Content.

If a medium contains Web Content, a file named README.TXT must be present in the root directory (may be present otherwise). The file must contain various information, e. g.
  • Contact information regarding the institution that created the medium
  • Information about the software used to create the medium
  • Information about any optional DICOM viewer contained on the medium

In particular, README.TXT is independent of the clinical information on the medium. Therefore, it is explicitly permitted to write the same README.TXT file to all media created by the same software.

DICOM Viewer

A DICOM viewer is an executable application used to visualize the DICOM objects on the medium. A medium can optionally contain one or more DICOM viewer applications.

It must be clear for the end user which file to be executed for launching the DICOM viewer. It is recommended to provide such information in the file README.TXT, if present on the medium. A DICOM viewer on the medium shall be able to run with normal user privileges, i. e. without administrator privileges, and must be able to correctly display all DICOM objects present on the same medium based on the requirements described in the DICOM standard. As an additional help, it is recommended to add a user's manual in PDF format to the medium and to provide a short manual in the inlet of the medium's jewel case.

Other Content

Other Content (i. e., files containing neither DICOM nor Web Content) can be stored in any format on the CD. Again, it is recommended to use a separate directory for Other Content. In contrast to the Web Content, there is no requirement for a DICOM counterpart to be present on the CD for this type of data.


The Requirements Specification for Exchange Media Containing Patient Information is a detailed specification defining the rules for content and formats that may be used on a patient CD. In combination with the guidelines for recipients of such CDs many possible sources of error should be eliminated.

Last page update: 2013-06-10
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