DICOM: A Look into its Scope and Utility

DICOM-short for Digital Imaging and Communications in Medicine-has become indispensable to any modern clinical setting that deals with medical imaging. Considering the ubiquitous need and utility of medical imaging in modern healthcare, the broad scope and application of DICOM is not hard to fathom. It allows the storage, viewing, and sharing of medical images and related data on devices within and across medical facilities.

What is DICOM exactly?

DICOM is the standard communications protocol used for capturing, storing, and transmitting medical images and related data. Phrased simply, DICOM in medical imaging acts as a blueprint for the information structures and procedures controlling the input and output of data in medical imaging systems. The term refers to both the protocol itself and its corresponding file format. All data obtained in the process of medical imaging is stored in this format. Without it, sharing information between different imaging devices would be significantly more difficult.

DICOM was released in 1993 as the third version of the ACR-NEMA standard—a protocol conceived in the 1980s with the purpose of enabling interoperability of medical imaging devices from different manufacturers. Since then, DICOM has been crucial in the development of modern radiology, having improved the workflow and sustainability of medical imaging systems immensely by allowing equipment, digital archives, workstations, and servers from different vendors to share information effortlessly.

What are the benefits of DICOM in medical imaging?

Medical imaging has a crucial role in healthcare at all major levels. Aside from providing key tools for clinical analysis and diagnosis, it is equally important for treatment itself. Without it, physicians would have to resort to invasive diagnostic methods far more often. Tracking progress during treatment would be far more difficult or impossible, and treatment of patients in follow-up care would not include as helpful databases for reference.

DICOM has become ubiquitous wherever there is medical imaging involved, from radiology, cardiology, oncology, nuclear medicine, radiotherapy, neurology, orthopedics, ophthalmology, dermatology, and dentistry, to veterinary medicine. Grasping its crucial role in creating interoperability between medical imaging devices and medical systems is vital for understanding what DICOM is in the first place and avoiding the confusion that arises when terms for medical information systems like PACS or RIS are introduced.

DICOM effectively satisfied the need for a standardized format for transferring medical images and data that emerged back in the 1980s when medical imaging and computing in clinical work were being introduced. This in turn provided many additional benefits, including

• Eliminating the need for physical storage – DICOM allowed imaging information systems to securely store medical images and data digitally.

• Reduced costs and space requirements – Digital storage is significantly less expensive than the storage needed for hard-copy films. DICOM-compliant systems are far more cost-effective and provide a space advantage over the traditional film archives.

• Better diagnosis and patient care – Access to information and diagnosis too were facilitated with the implementation of DICOM. The interoperability of DICOM-compliant devices ensures that medical data can be accessed by physicians worldwide. Telediagnosis, distance education, and accelerated peer review, consultation, and diagnosis are made possible. All of this provides a means for effective cooperation in the diagnostic process and better overall patient care.

• Improved workflow – Manual filing, retrieval, and transport of folders are a thing of the past in medical imaging systems using DICOM. Faster image retrieval and the ability to access the images remotely allow physicians to work at a much quicker pace.

• Easier access to patient data – DICOM-compliant systems offer more organized and convenient management of medical information. All patient data can be reached through a single point of access as images are integrated into the hospitals’ databases of DICOM images and related data.

• Additional imaging services – DICOM provides many additional imaging services, including managing imaging procedure worklists, printing images on film or digital media like DVDs, reporting procedure and archiving status, encrypting datasets, organizing layouts of images, encoding ECGs, CAD results, and structured measurement data, to list a few. DICOM-compliant imaging devices with diagnostic monitors enable clearer visualization of images in comparison to the traditional viewing of images on light boxes.

Public and private hospitals, diagnostic centers, analysis laboratories, and an increasing number of smaller practices all use DICOM-compliant medical imaging technology. NEMA states that all major vendors of medical imaging technology use DICOM, and that every medical profession using medical imaging will soon be using DICOM.

Which devices use DICOM?

It’s probably clear so far that DICOM’s core use lies in its ability to resolve compatibility issues between various devices of different manufacturers. But which devices does this apply to exactly?

Access to databases of DICOM images and data is available on any device with adequate DICOM-compliant software installed. That includes

• Image acquisition devices such as computed tomography (CT), magnetic resonance imaging (MRI), ultrasound imaging, computed radiography, fluoroscopy, angiography, mammography, breast tomosynthesis, PET (positron emission tomography), SPECT (single photon emission computed tomography), endoscopy, microscopy, whole slide imaging, and OCT (optical coherence tomography) devices

• Image archives, e.g. VNAs

• Image processing devices – image viewers, diagnostic workstations, 3D visualization systems, clinical analysis applications, scanners, media burners, and importers

• Hard-copy output devices like photographic transparency films and paper printers

• Devices included in medical IT systems such as PACS (Picture Archiving and Communication Systems), CAD (Computer-aided Detection/Diagnosis Systems), RIS (Radiology Information Systems), and EMR (Electronic Medical Record) systems

Can DICOM viewers be used with PCs and mobile devices?

When it comes to PC devices, various types of DICOM viewers are often available for all major operating systems such as Windows, macOS, and Linux. As for the availability of mobile DICOM viewers, a vast number of mobile applications for viewing DICOM images have been developed, many of them free of charge.

What’s the tech behind DICOM?

The DICOM Standard specifies an upper layer protocol (ULP) that is compatible with TCP/IP (Transmission Control Protocol and Internet Protocol), enabling its usage over the Internet. The protocol is used independently of the physical network which enables versatile application including communication using various forms of Ethernet, VPNs, remote access connections (such as by modem, ISDN or DSL), and via satellite, to name a few.

DICOM includes protocols for:

• Exchange of objects such as images and documents

• Query and retrieval of such objects

• Image compression

• 3-D visualization

• Image presentation

• Printing images

• Workflow management and results reporting

The issue of image consistency has been resolved by developing a table with digitally assigned pixel values called the DICOM grayscale standard display function (GSDF).

DICOM’s various features adopt international standards, for example:

• TLS or ISCL for network confidentiality and peer authentication

• JPEG, lossless JPEG, JPEG 2000, or run-length encoding (RLE) for image compression

• ISO 9660, UDF, and other file systems compatible with conventional software

When it comes to encryption, the DICOM Standard does facilitate data encryption, but its implementation is entirely dependent on DICOM service providers and medical facilities using these services. Manufacturers of DICOM-compliant products can choose to not implement encryption in their services in which case the medical facilities using such unencrypted DICOM have the option of setting up encrypted VPN networks. The effectiveness of such security solutions is disputable.

The DICOM Standard is continuously being updated to keep up with the changing demands of medical imaging systems. Among the vast number of medical imaging vendors selling DICOM-compliant products, the majority actively participate in these enhancements.

What’s the difference between DICOM and PACS, RIS, and CIS?

Terms such as PACS, RIS, and CIS are often mentioned alongside DICOM, especially when talking about the benefits that modern software tools, standards, and protocols have introduced to healthcare. This may lead to some confusion with regard to what distinguishes them, particularly when it comes to the difference between PACS and DICOM.

The former are medical IT systems based on networks of various devices. DICOM is the universal file format and protocol which specifies the communication between these devices and enables the same between multiple different systems.

Now that that’s clear, here’s an overview of the most common medical IT systems:

• PACS (Picture Archiving and Communication Systems) are medical imaging systems which provide storage and access to images from multiple modalities. Its main application is as a superior storage option which eliminates the need for manual storing and retrieval of data.

• RIS (Radiology Information System) – another type of information system for storing and managing medical imaging data commonly used in radiological practices. It is usually used by radiologists for scheduling patients, tracking and interpreting examinations, and billing, among other functions.

The distinction between RIS and PACS might be a little unclear since they are applied within the same field and often used in conjunction. They are both systems for facilitating the handling of patient information, but while PACS provides storage and a long-term solution for managing patient data, RIS streamlines processes and improves workflow by enabling patient tracking in real time and providing one central source patients’ medical records.

• EHR (Electronic Health Record) – EHRs are digital versions of patients’ paper charts. They are digital records of patients’ entire medical treatment histories. This includes medical images. Just like the previously mentioned systems of patient data, EHRs can work in conjunction with other medical information systems. They can come with a DICOM output, send, or client, and they can also be integrated with PACS or RIS.

• CIS (Clinical Information System) – An information system for recording, storing, and manipulating patients’ clinical information. How does this differ from EHRs, you may wonder? EHRs contain the entire medical history of a patient and are therefore much more generalized. CIS handle very specific information, collected directly from equipment and medical personnel inputs.

Along with providing countless benefits like improving workflow and efficiency, reducing costs and space requirements, these medical information systems enable practices to focus more of their efforts around patient care. This has made them indispensable in modern medical facilities.

What’s the best DICOM viewer for you?

DICOM viewers are an integral part of DICOM-compliant systems. If you already have a system that supports DICOM, a standalone DICOM image viewer is most probably not necessary. But if that’s not the case, or there’s difficulties in communication with or access to a PACS or RIS system, getting a DICOM viewer might prove to be the best decision if you wish to start viewing medical images.

There is a great number of DICOM image viewers readily available in every price range and various scopes of application. How to know which one’s the right fit? What criteria to go by? To start with, you should take into consideration the type of devices you plan to view the images on, the desired features, the type of operating system, and your budget requirements.

Here are just a few of the most popular DICOM viewers on the market:

• 3DimViewer – This DICOM viewer is an open-source 3D viewer and therefore available for customization and integration with other programs. It is one of the most flexible viewers available as it’s accessible for Windows, Macintosh, and Linux-based platforms. On top of that, it’s also free of charge. Editing features are reduced to the most basic options like brightness and contrast. One of its best features is volume and surface renderings with thresholding-based tissue segmentation. Something to take into consideration is the GPU acceleration needed for volume rendering.

• Horos DICOM viewer – Another free, open-source DICOM image viewer. It is available for Macintosh devices and is based on OsiriX and other open-source medical imaging libraries.

• DICOM Web Viewer (DWV) – This viewer can be used on almost any device with almost any browser as it’s an entirely browser-based DICOM viewer. As 3DimViewer, it is a view-only system with minimal editing features. Incorporating it into PACS servers is also possible with some coding.

• Mango – alternatively Multi-image Analysis GUI, supports multiple image and surface rendering formats and can create custom formats and filters. It offers many editing, analysis, and processing features and is available on Windows, Macintosh, and Linux desktops, browsers, or iPads. It is also free of charge for non-commercial use.

• MicroDicom – This DICOM viewer offers an intuitive user interface and all of the most common features for manipulation of DICOM images. It is available on Windows and like many other free DICOM viewers, grants free access for non-commercial use.

Medical technology is constantly improving and diversifying to adapt to the complex demands of medical imaging systems. New types of DICOM-compliant software are developed constantly, and one of the most interesting developments to arise from this have been cloud-based DICOM image viewers. Our very own DICOM viewer, PostDICOM, is based on this concept. Cloud-based DICOM image viewers enable viewing and processing DICOM files online without the need to install any software on client devices.

Our DICOM viewer comes with free trial of cloud space which can be expanded by choosing a paid subscription to the service. It is supported across all major platforms (Windows, macOS, Linux, IOS, and Android), and equipped with advanced viewing tools. PostDICOM also acts as a cloud-based PACS server, enabling DICOM files to be stored in the cloud while preserving the functions of regular PACS systems relying on local servers. Security is prioritized as all transmissions are SSL (Secure Socket Layer) encoded and files are able to be additionally secured by assigning passwords.

The benefits of using DICOM-compliant software in the process of medical imaging are self-evident, and whether a facility requires intricate DICOM-compliant systems or simple DICOM viewers to start out with, there is more than enough options available out there to choose from, and the great thing about free DICOM viewers is that there’s nothing to lose in trying them out.