DICOM decides how a CT, MRI, X-ray or ultrasound machine saves a picture and how it travels across your network. This guide explains the files, the tags, the network services and why a DICOM image is not a JPEG.
DICOM stands for Digital Imaging and Communications in Medicine. It is two things at once: a file format that keeps the picture and the patient details in one object, and a set of network rules that lets machines and software exchange those objects without a pen drive.
Because the standard is agreed across the industry, a scanner from one maker can hand a study to software from another. Without DICOM, every machine would write its own kind of file and every centre would be locked to one supplier.
Open an ordinary photograph and you get pixels. Open a DICOM object and you get pixels plus hundreds of labelled fields describing the patient, the machine and the scan.
Each field is called a tag and has a fixed number, so software written anywhere knows where to find the patient name or the slice thickness. Staff rarely see tags, but they are what lets a study be searched and matched to the right person years later.
DICOM arranges everything in four levels. One patient has many studies. One study has several series, for example a plain and a contrast series in the same CT sitting. Each series holds the images. When a viewer shows today's scan beside one from two years ago, that hierarchy is doing the work.
Keeping the identity inside the object means a study cannot drift from its patient when it is copied, backed up or sent to a radiologist. It also means a typing mistake at the machine follows the images everywhere, which is why a worklist matters.
Engineers talk about DICOM services in code words. Here is what each does in ordinary language and where you will meet it.
At the end of a scan the machine opens a connection to an agreed address on your network and sends the study across. The receiving software is usually called a DICOM server or an archive. Setup is a short form on the console: address, port and a short name for the destination.
Instead of typing a name at the console, the machine asks a worklist service for the patients booked today and the technician picks the right row. See what is a DICOM modality worklist.
A viewer, a second site or a reporting station can search the archive by patient identifier or date and ask for a study to be sent. This is how a radiologist elsewhere gets prior scans without burning a disc.
One more term turns up in quotations. An AE title is the short name a device answers to on the network.
Centres often ask why they cannot export pictures and email them. The comparison below explains what is lost.
| DICOM object | JPEG or PDF export | |
|---|---|---|
| Patient identity | Inside the file, in fixed fields | Only if somebody typed it on the image |
| Grey levels | Full range captured by the detector | Reduced to what a normal screen shows |
| Window and level | Adjustable after the scan, so soft tissue and bone can both be examined | Fixed at the moment of export |
| Measurement | Real distances, because pixel spacing is recorded | Not reliable |
| Good for | Reading, comparison, archive | Showing a patient one picture on a phone |
An exported image is fine as a courtesy copy and useless as a record. Keep the DICOM study in the archive and treat flat pictures as something generated from it.
A DICOM viewer opens studies and lets you scroll, window and measure. A DICOM server receives and keeps them. A full archive, explained in what is PACS, does both and adds reporting, sharing and history.
Elevate Aura builds a zero-download browser DICOM viewer and DICOM server software that receives studies automatically from the machine, as part of AuraPACS.
Digital Imaging and Communications in Medicine. It covers the format used to save medical images and the network rules machines use to send them.
You need a DICOM viewer, because ordinary photo software cannot read the format. Desktop viewers handle a single disc, and archive systems open studies in a browser with nothing installed.
The standard is published and open, so any manufacturer may implement it and there is no licence fee for the format. What you pay for is software that implements it well and the support behind it.
Most units sold in the last two decades do, although the option is sometimes a paid module nobody switched on. Ask your service engineer to check the console settings.
Not the objects themselves, because the messenger compresses images and strips the record. What can be shared is a secure link to the study and report, which is how AuraPACS reaches a referring doctor without a login.
DICOM is a standard, not a product. PACS is the software that uses it to receive, store, display and share studies. Owning a scanner that speaks DICOM does not give you a PACS.
Tell us how your centre or business works today and we will tell you plainly which parts of this apply to you, and which do not.
Founder-led · Chennai, India · Built and supported by the person who wrote it