Security of patient and study data associated with DICOM images when transferred using compact disc media

Abstract

The transmission of patient and imaging data between imaging centers and other interested individuals is increasingly achieved by means of compact disc digital media (CD). These CDs typically contain, in addition to the patient images, a DICOM reader and information about the origin of the data. While equipment manufacturers attach disclaimers to these discs and specify the intended use of such media, they are often the only practical means of transmitting data for small medical, dental, or veterinary medical centers. Images transmitted by these means are used for clinical diagnosis. This has lead to a heavy reliance on the integrity of the data. This report describes attempts to alter significant patient and study data on CD media and their outcome. The results show that data files are extremely vulnerable to alteration, and alterations are not detectable without detailed analysis of file structure. No alterations to the DICOM readers were required to achieve this; changes were applied only to the data files. CDs with altered data can be readily prepared, and from the point of view of individuals viewing the images, function identically to the original manufacturer's CD. Such media should be considered unsafe where there is a potential for financial or other gain to be had from altering the data, and the copy cannot be cross-checked with the original data.

Fig. 1

Screen capture showing detail of the DICOM tag editor in DicomWorks. Changes to the fields “Patient name”, “Patient ID”, “Study Date” and “institution” have been completed.

Fig. 2

Screen capture of the image display window provided with the Agfa DICOM viewer. The image shows the thorax of a dog. Altered fields are seen in the upper menu bar and superimposed on the image. The accession number superimposed on the image marked “ACCESS#” differed from the number in the menu bar. The source of the number in each location differs and data at both locations were altered.

Fig. 3

Screen capture from the opening dialog of the eFilm™ Lite™ software used by Fuji. The data in the list field is taken from the altered “dicom.dir” file made by DicomWorks”. The user selects the study, and by mouse clicking, opens the (altered) images in the usual fashion.