Significance and Use
3.1 The primary use of this guide is to provide a standardized approach for the data file to be used for the transfer of digital radiological data from one user to another where the two users are working with dissimilar systems. This guide describes the contents, both required and optional for an intermediate data file that can be created from the native format of the radiological system on which the data was collected and that can be converted into the native format of the receiving radiological data analysis system. This guide will also be useful in the archival storage and retrieval of radiological data as either a data format specifier or as a guide to the data elements which should be included in the archival file.
3.2 Although the recommended field listing includes more than 100 field numbers, only about half of those are regarded as essential and are marked Footnote C in Table 1. Fields so marked must be included in the data base. The other fields recommended provide additional information that a user will find helpful in understanding the radiological image and examination result. These header field items will, in most cases, make up only a very small part of a radiological examination file. The actual stream of radiological data that make up the image will take up the largest part of the data base. Since a radiological image file will normally be large, the concept of data compression will be considered in many cases. Compressed data should be noted, along with a description of the compression method, as indicated in Field No. 92 (see Table 1).
(A) Field numbers are for reference only. They do not imply a necessity to include all these fields in any specific database nor imply a requirement that fields used be in this particular order.
(B) Units listed first are SI; those in parentheses are inch-pound (English).
(C) Denotes essential field for computerization of examination results, regardless of examination method.
(D) Denotes essential field for radiographic examination.
(E) Denotes essential field for images with more than 8-bit gray scale.
(F) Denotes essential field for radioscopic examination.
3.3 This guide provides a data file for a single image. It is recognized that a complete examination record may contain several files for the same examination method in different areas, with or without image processing, for different examination methods, and for variations within a single method (for example, different x-ray energies). This file will permit the examination of a single image and will include information about the existence of other images and records for the examined object. This single image may be one created by overlaying or processing results from multiple examination approaches, for example, data fusion. For such images, the notes sections must clearly state how the image for this file was created.
3.4 The Guide E1475 data fields are assigned at the TIFF group with Tag 50983, called Data fields of Guide E1475 using XML as format for the data fields. The tag may be used by any user without restrictions. The Extensible Markup Language (XML) is a simple, very flexible text format derived from SGML (ISO 8879). It is used to store all required information of Guide E1475 within one TIFF Tag. Annex A1 provides more information and an example.
Scope
1.1 This guide provides a listing and description of the fields that are recommended for inclusion in a digital radiological examination data base to facilitate the transfer of such data. This guide sets guidelines for the format of data fields for computerized transfer of digital image files obtained from radiographic, radioscopic, computed radiographic, or other radiological examination systems. The field listing includes those fields regarded as necessary for inclusion in the data base: (1) regardless of the radiological examination method (as indicated by Footnote C in Table 1), (2) for radioscopic examination (as indicated by Footnote F in Table 1), and (3) for radiographic examination (as indicated by Footnote D in Table 1). In addition, other optional fields are listed as a reminder of the types of information that may be useful for additional understanding of the data or applicable to a limited number of applications.
1.2 It is recognized that organizations may have in place an internal format for the storage and retrieval of radiological examination data. This guide should not impede the use of such formats since it is probable that the necessary fields are already included in such internal data bases, or that the few additions can easily be made. The numerical listing and its order indicated in this guide is only for convenience; the specific numbers and their order carry no inherent significance and are not part of the data file.
1.3 Current users of Guide E1475 do not have to change their software. First time users should use the XML structure of Table A1.1 for their data.
1.4 The types of radiological examination systems that appear useful in relation to this guide include radioscopic systems as described in Guide E1000, Practices E1255, E1411, E2597, E2698 and E2737, and radiographic systems as described in Guide E94 and Practices E748, E1742, E2033, E2445, and E2446. Many of the terms used are defined in Terminology E1316.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
