Identity
Which object is this?
The SOP Class UID identifies the object type. The SOP Instance UID identifies the individual object.
The interoperability library
Understand and de-identify DICOM imaging data.
Understand the patient information medical images carry, and the considerations behind de-identifying DICOM data for sharing.
Medical imagingDICOM & FHIRBy Hgear
DCM, explained
A medical image carries more than pixels.
In medical imaging, a .dcm file usually holds a DICOM object. DICOM stands for Digital Imaging and Communications in Medicine. An image object brings scan data and descriptive information together, so software can interpret the image in its study context.
In practiceThe basics
One file, one SOP instance.
A standard Part 10 file contains one SOP instance: an individually identified DICOM object. That object is not necessarily an entire examination. Think of a DCM file as one part of an imaging study, with both image content and structured context.
SOP instanceStudy context
In practiceInside the file
What’s inside the file?
The file begins with information that helps a reader identify and decode the dataset that follows. A Part 10 header includes a 128-byte preamble, the DICM prefix, and file meta elements. The SOP Class UID identifies the object type, the SOP Instance UID the individual object, and the Transfer Syntax UID how the dataset is encoded.
SOP Class UIDTransfer Syntax UID
In practiceSharing
Keep the original. Share with context.
A JPEG or PDF export can be useful for a presentation, but it does not preserve the complete DICOM object. Retain the original study when image metadata and full image information matter.
Retain the studyExport with care
In practiceDICOM meets FHIR
Where DICOM meets FHIR.
DICOMweb defines HTTP-based services for managing and distributing DICOM objects. FHIR’s ImagingStudy resource describes a study, its series and instances, and the endpoints used to access them. The images remain in an imaging repository; ImagingStudy supplies a structured description and retrieval references.
DICOMwebImagingStudy
Features
Open, de-identify and connect imaging data.
Use a DICOM viewer that supports your study’s format, keep the complete study together, and review every place identifying information can hide before sharing.
Encoding
How is it read?
The Transfer Syntax UID specifies how the following dataset is encoded, including its compression rules.
Getting started
Gather the complete study.
Keep the supplied files and folder structure together. Import the study folder or its DICOMDIR index when your viewer supports it.
Getting started
Import into a compatible viewer.
Select the study, then browse its series and images. A standard photo application may not understand the file.
Getting started
Check the study context.
Confirm the study details before using or sharing an image. Use your organization’s approved workstation for clinical interpretation.
Handling the data
De-identification goes beyond a filename.
Patient information can appear in attributes, overlays, and the pixels themselves. DICOM confidentiality profiles support a broader de-identification process; applying them alone does not guarantee that all identifying information is removed.
The connected workflow
From an imaging study to a shareable, connected record.
DICOMweb gives HTTP access to imaging objects, and FHIR ImagingStudy connects the study to the wider clinical record while the images stay in the imaging repository.
Security & trust
De-identification goes beyond a filename.
Confidentiality profiles
DICOM confidentiality profiles support a broader de-identification process, but applying them alone does not guarantee that all identifying information is removed.
Attributes
Patient information appears in DICOM attributes such as names, identifiers and dates.
Overlays
Identifying text can be embedded in overlays and annotations layered on the image.
Pixel data
Burned-in text inside the pixels themselves must be reviewed as well.
Keep the original
Retain the complete study; JPEG or PDF exports do not preserve the full DICOM object.
Who it is for
For teams sharing medical imaging data.
Understand what a DICOM file carries before it leaves your organization, and how it connects to the rest of the clinical record.
Imaging ITResearch teamsIntegration engineers
- Know which object a file holds and how it is encoded
- Keep studies complete when importing or transferring them
- Review attributes, overlays and pixels before sharing
- Connect studies to FHIR through ImagingStudy and DICOMweb
Common questions
DICOM De-identification FAQ
Are DCM and DICOM the same thing?
DICOM is the standard; .dcm is a commonly used file extension. A filename alone cannot establish whether its contents conform to DICOM.
Does one file contain the whole scan?
Not necessarily. A study can contain multiple series and many separate instances. Keep the complete study together when importing or transferring it.
Can a FHIR ImagingStudy contain the images?
The ImagingStudy resource describes the study and how to access its instances. The DICOM instances themselves are stored separately, for example on a DICOMweb server.
Bring your healthcare data into focus.
Explore Hgear’s guides and tools for understanding structured healthcare data.
Talk to the Hgear team
ImagingStudy is one of many FHIR resources; the guide covers resources, APIs, profiles and validation.