How to view a .DCM file online
For patients, students and anyone who got a CD from the hospital.
Find your file
On an imaging CD look in the DICOM folder. Files are often named like IM00001 with no extension. Drop one here.
It opens right away
Your .DCM file is opened, header and pixels alike.
Look, scroll and measure
Drag to change brightness, use presets like Lung or Bone, scroll through slices and measure in millimetres.
Supported DICOM files
DICOM stores pixels in several encodings. Here's what supported.
| Encoding (transfer syntax) | Typical source | Status |
|---|---|---|
| Uncompressed (Implicit / Explicit VR, little and big endian) | Most CT and MRI exports, research data | Full |
| Deflated Explicit VR | Some archives and web exports | Full |
| RLE Lossless | Ultrasound, nuclear medicine, older PACS | Full |
| JPEG Baseline (8-bit) | Ultrasound, endoscopy, secondary captures | Full |
| Multi-frame & cine | Enhanced CT/MR, ultrasound loops, angiography | Full |
| JPEG Lossless, JPEG-LS, JPEG 2000, HTJ2K | Compressed PACS archives, CR/DX X-ray | Tags only, image soon |
| DICOMDIR | Index file on imaging CDs | Lists the CD, open images directly |
What is a .DCM file?
The format behind almost every medical image.
A DCM file is a DICOM medical image (an X-ray, CT, MRI, ultrasound, or mammogram) bundled with patient and study information. To open it, use a free DICOM viewer: MicroDicom on Windows, Horos on Mac, or Weasis on any platform. Standard photo apps cannot open these files because they do not understand DICOM's medical structure.
Programs that open .DCM files
| Full name | DICOM Medical Image |
|---|---|
| Developer | NEMA (National Electrical Manufacturers Association) / DICOM Standards Committee |
| First released | 1993 (DICOM 3.0); predecessor ACR-NEMA 1985 |
| Category | 3D & CAD |
| MIME type | application/dicom |
| Signature | 44 49 43 4D "DICM" |
Related viewers
More free tools for images and technical files.
Is my .DCM file uploaded anywhere?
No. Your .DCM file is decoded by JavaScript. Nothing, including patient details, is sent to FileExtension.org. You can even disconnect from the internet after the page has loaded.
Which file on my hospital CD should I open?
Open the DICOM folder and drop any image file from it. Files are usually named like IM000001 or have random numbers and no extension. The DICOMDIR file is just an index.
Why is my image completely white or black?
The display window may not suit the image. Pick Full range or another preset, or drag on the image: up and down changes brightness, left and right changes contrast.
Can I hide my name before sharing a screenshot?
Yes. Turn on Anonymize view: patient name, ID, birth date and institution are hidden on the image and in the tag list. The original file is not changed.
Can I use this to make a diagnosis?
No. This is a free viewer for looking at your own images and learning. It is not certified medical software. Always rely on your doctor's report.
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