DICOM Files IPO Prospectus: Pioneering Global Standard for Medical Imaging and Communications
What Is DICOM
Digital Imaging and Communications in Medicine (DICOM) is a standard for the processing, storage, printing, and transmission of medical images. It includes definitions for file formats and network communication protocols.
This communication protocol is an application-level protocol based on TCP/IP, which connects various systems via TCP/IP. Between two medical devices capable of accepting DICOM, image data and patient information can be received and exchanged through files in DICOM format.
The National Electrical Manufacturers Association (NEMA) holds the copyright to this standard agreement. DICOM enables the integration of medical imaging devices, servers, workstations, printers, and network equipment from different manufacturers into Picture Archiving and Communication Systems (PACS). DICOM has been applied in many fields such as radiology, cardiology, pathology, and dentistry. It is widely adopted by hospitals and sees smaller-scale use in dental practices and general clinics. The DICOM standard establishes a unified international standard for the transmission of medical images and related information between computers. By connecting to the internet through data interfaces, remote transmission of medical image information becomes possible, enabling applications such as off-site consultations and telemedicine. These capabilities undoubtedly significantly improve diagnostic efficiency and accuracy, holding substantial practical significance.
History of DICOM Development
In the early 1980s, although radiologists and medical physicists both hoped to use images for radiotherapy dose planning, it was challenging at the time to decode images using Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) equipment. In 1983, the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) jointly established a standards committee. Their first standard agreement, known as ACR/NEMA 300, was published in 1985. Shortly thereafter, due to issues such as ambiguity and inconsistencies, a second, improved version was released in 1988, which gained support from more vendors. In 1992, the U.S. Army and Air Force carried out large-scale deployment of ACR/NEMA technology. In 1993, the third version was published, and the agreement was renamed “DICOM” to enhance its international recognition. Although the official latest version is considered to be Standard Agreement 3.0, the content of the agreement has continued to be updated and expanded since 1993. Moreover, its naming convention no longer relies solely on version numbers but instead uses the year of publication, such as “DICOM 2007.”
DICOM Data Format
Unlike most data formats, DICOM consolidates information into a single dataset. For instance, if a chest X-ray image contains patient identifiers such as the patient ID, it is virtually impossible for the image to be inadvertently separated from the associated patient information. This principle is analogous to JPEG image files, which embed tags that identify or describe the image. A DICOM object comprises numerous attributes, including the patient’s name, ID, and the specific attribute containing the image’s pixel data.
DICOM Services
DICOM encompasses numerous service classes, most of which are related to network data transmission; the following data formats are all associated with it to some extent.
1. Storage
The DICOM Storage Service is used to transmit images or other Persistent Objects, such as sending organized medical records to PACS systems or workstations.
2. Storage Confirmation
This service is designed to verify whether an image has been permanently stored in a specific location (such as redundant hard drives or other media). Based on the information provided by the service provider, users of this service can confirm whether the original image has been securely deleted.
3. Image Acquisition
This feature enables the workstation to locate a series of images or other subjects and then retrieve them via the PACS system.
4. Task List
This feature enables imaging equipment to electronically receive detailed patient information and scheduled examinations, thereby avoiding duplicate data entry or errors resulting from such redundancy.
5. Process Record
This feature is an add-on service for the worklist, providing the capability to transmit additional data related to an examination, such as imaging data, start time, end time, duration, and medication dosage. It helps radiology departments optimize resource utilization.
6. Print
DICOM Print Service transmits images to a DICOM printer, typically outputting "X-ray" images, and employs a standardized calibration procedure to ensure image consistency across different display devices.
7. Offline Media (Documents)
This service describes how to store medical imaging information on removable media. DICOM filenames are limited to 8 characters, and the standard requires the presence of a media directory, specifically the DICOMDIR file. Since DICOMDIR provides far more comprehensive information than any filename could, the semantic meaningfulness of the filename is irrelevant.
Limitations of DICOM
In a paper presented at an international academic symposium in 2008, it was noted that DICOM has deficiencies in data entry. “A major drawback of DICOM is the possibility of incorporating too many optional information groups. This shortcoming is primarily manifested as inconsistency in data population; blank fields and erroneous data in certain attributes may compromise the integrity of the image subject.” Moreover, the DICOM standard is mainly designed to address interoperability issues in the field of medical imaging, and it is not a particularly useful framework or structure for clinical workflows.
DICOM in China
Over the past decade, China has imported a large number of advanced medical imaging devices from abroad, which have played a crucial role in promoting the development of the medical and healthcare sector. However, due to various reasons, most of these medical imaging devices and systems were not designed with functionalities for the storage and communication of images and associated medical information. The DICOM 3.0 standard is relatively new and quite extensive; currently, there is very little research on it in China, and systems implementing its functionalities are virtually nonexistent.
On February 10, 2015, the China International DICOM Standards Committee (CIMICS) convened in Chengdu a preparatory meeting for its leadership transition and an expert symposium on conformance testing for the Chinese version of the DICOM standard. The meeting focused on discussing the evaluation framework, testing specifications, technical architecture, and testing procedures for conformance testing against the Chinese DICOM standard, and summarized four key points for the next steps in DICOM Chinese conformance testing:
First, the test content should be enriched; DICOM Chinese conformance testing should gradually expand its scope based on the Chinese standards for testing.
Second, the testing tools must be validated. The DICOM testing tool has been completed; the next step is to undergo validation by a professional testing institution to ensure its scientific rigor, fairness, and usability.
Third, the testing protocol should be further improved. Specifically, the protocol needs to be more detailed, and the grading of test results should be more granular.
Fourth, the Chinese DICOM Standard and the Chinese DICOM Conformance Test Specification should be released as soon as possible to provide robust assurance for DICOM testing.
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Author: Liu Nan