Electronic medical of document circulation formats Hl7 and DICOM

This article discusses electronic medical document circulation formats HL7 and DICOM, building structures of medical data formats and transmission information through open communication ViPNet.

Development of electronic medical document leads to higher quality of medical work and simplification of time. Under electronic health understood development, transfer and storage of medical data in a specific format, which was adopted by the international standard for electronic medical document HL7 and DICOM. DICOM is used mainly where you want to work with medical images (X-ray, Radiology, and Ophthalmology). Transferring images the most widely used standard DICOM (Digital Imaging and Communications in Medicine), developed by the American College of Radiology and the National Association of electronics manufacturers (ACR / NEMA). In addition, other communication standards (HL7, X12) using the DICOM standard format for transferring images [1;4].

For effective work requires more than a simple connection of equipment through cables. A comprehensive solution for managing all diagnostic information, starting with the input images to the backups. DICOM standard allows us to solve the problem of integration based on open architecture. DICOM allows you to organize not only the transfer of data over the network, but also automatic data processing [2]. It significantly reduces the time of preparation and research, image management, and related information. To achieve the highest efficiency, it supports all stages of diagnosis, reducing costs by:

-       Reducing the time of service;

-       Failure of the films and the cost of storage;

-       Drastic reduction of losses of images and results.

For minimal changes to existing standards expected based on the overall data model to specify the area in which it is preferable to use one or the other standard [2;3]. So HL7 standard to be used to provide interactive data in hospital infrastructure, X12 — to work with medical information dialup [2;3]. Currently, ASTM and HL7 already have a common format for the clinical data, and develops X12N format incorporating HL7 messages for the introduction of detailed clinical data in the format of X12 [2;3]. In medical equipment data have aching from the usual difference. As can be understood in the computer storage of medical equipment [2;3]. DICOM enables the integration of both hardware compatible with it, and the early models of the equipment without communication capabilities using DICOM-converters. Converter provides transfer of commands and data in the format of the standard equipment, and vice versa. It can be realized based on the general purpose computer or a dedicated microcontroller. Equipment that is compatible with the standard DICOM, just connect to the network [2;3]. At this level, the various stations are arranged as diagnostics and analysis. It is advisable to use a separate DICOM-server for printer and digitizer (scanner). Second level controls images, spanning several departments. Images Administrator job of managing subordinates archives. At this level can also connect various equipment and servers.The third level is for controlling the entire information distribution time of use of equipment, etc [2;3]. It provides access to a radiology information system, and through it to the hospital information system.

We can distinguish the following basic technology for image input [2;3]:

-       Direct digitization of images (computer radiography equipment);

-       Reconstruction of the image of Samples (CT, MRI, ultrasound equipment);

-       Digitize the analog video signal from the medical equipment.

For data transfer in the internal infrastructure department based on the local network (LAN) is preferably used Ethernet, or more high-speed technology (Fast Ethernet, ATM, FDDI). Application of the standard ISO / OSI model and the TCP / IP protocol provides connectivity from almost any type of platforms: DOS / Windows, Unix, Mac, etc. When connecting to remote clinics and research centers across wide area networks (WAN) key elements are speed and cost. Universally widespread Internet allows you to organize data virtually anywhere in the world and achieve the required cost / speed by selecting the type of access (modem, dial-up, direct connection) [2;3].

DICOM restricts the set of valid characters used in the message, nine tables encodings of ISO 8859. Provided the second half of encodings for Latin, Cyrillic, Arabic, Greek and Hebrew. Ranking byte binary words (due to different types of processors), and the presence of field VR, depends on the type of transfer syntax [2;3]:

1.                  Items are sent without a field data type (data type is determined by tag), in the words of (tag, length, data type binary) are first passed the low order; bytes;

2.                  There is a field data type, first low bytes transferred;

3.                  There is a field data type, upper bytes transmitted first.

Commands to the specification of the operations and establish a connection. Command sequence is constructed from the command elements defined protocol element DIMSE, similar to the data sequence. Team members do not have a field of type (VR) and transmitted in order of increasing tag number, first go low bytes. The standard accounts all elements of DICOM- posts and unique identifiers for the transfer syntax and SOP- classes. For elements defined tags, data types, and a list of predefined values ​​(if necessary) [2;3].

DIMSE service enables you to move messages between SOP- classes and determines [2;3]:

-       Procedures and rules for coding messages;

-       Service primitives (request, response, mapping, validation);

-       Support communication between users (both synchronous and asynchronous);

-       Coordination and execution services (save, transfer and retrieval of information).

Standard introduces the service top-level of the OSI model to support DICOM- exchange messages between applications, allowing you to connect, send messages, and close the connection [2;3].

DICOM v3.0 can use the following protocol stacks:

-       •Satisfying the protocol stack specification ISO/OSI;

-       •Upper-layer protocol for TCP/IP, providing necessary services and functions stack OSI;

-       protocol stack with a dedicated connection for compatibility with previous versions of the standard [2;3].

Expected results consists of:

-          The practical importance of data protection;

-          Registration of the patient passport data in its own database

-          Registration, accumulation and storage in a database of digital X-ray images

-          Maintains a database of X-ray images, which allows you to report, sort, and retrieve information on patient's name, type of study

-          Export images in accumulated other information systems in the format DICOM (example, for transmission over networks Internet / Intranet for international standard storage and transmission of medical images for teleconferencing, seek advice from the experts and operational training to receive the patient).

-          Saving images to a file format BMP, TIFF and JPEG.

-          Preparation of patient data in electronic form in accordance with the requirements;

-          Direction of patient data, according to the list of indications for consultation body.

References:

1.                  Review of ICT development in Uzbekistan 2006–2008, ICTP_Review_2008_RU_part_07.

2.                  Jeffrey S.Blair. The Biomedical Engineering handbook, 1995, pp. 2650–2659.

3.                  American College of Radiology, National Electrical Manufacturers Association, «ACR-NEMA.

4.                  RFC 791, Internet Protocol, DAPRA Internet Protocol Specification.