DICOM Viewer — Open .dcm Medical Images with XnView

DICOM (Digital Imaging and Communications in Medicine, .dcm) is the standard file format for medical imaging — CT, MRI, ultrasound, X-ray, mammography and more — maintained by NEMA since 1985. XnView MP reads DICOM files natively on Windows, macOS and Linux, including multi-frame series, and can convert single frames to JPEG, PNG or TIFF. XnView MP is a general image viewer, not a certified medical diagnostic device.

XnView DICOM support at a glance

About the DICOM format

DICOM was introduced in 1985 by the American College of Radiology and the National Electrical Manufacturers Association (ACR-NEMA) and is now maintained jointly as an international standard. It defines both a file format and a network protocol for storing and transmitting medical images and associated information. A DICOM file is a container that bundles one or more image frames (a single X-ray, a stack of CT slices, an MRI volume, an ultrasound cine loop) with structured metadata about the patient, the study, the series and the modality. Imaging modalities such as CT, MRI, PET, ultrasound, mammography, fluoroscopy, dental imaging, ophthalmology and others all use DICOM as their native format.

Key characteristics of DICOM

How to view and convert DICOM files with XnView

Open a .dcm file

Launch XnView MP, then File > Open and select the DICOM file, or drag it onto the XnView MP window. Multi-frame DICOMs open on the first frame; use Page Up / Page Down or the Pages side panel to navigate through the series.

Convert DICOM to JPEG, PNG or TIFF

In XnView MP: File > Save as, then pick the output format. For batch conversion of a whole study, open XnConvert, drag the DICOM files in, choose the output format in the Output tab and click Convert.

Important — diagnostic disclaimer

XnView MP renders DICOM images for general viewing purposes only. It is not certified as a Software as a Medical Device (SaMD) under FDA, EU MDR or comparable regulations. Clinical interpretation must rely on a regulator-approved DICOM viewer running on a calibrated medical display, with the appropriate window / level controls and quality assurance.

Frequently asked questions

Does XnView open DICOM (.dcm) medical images?

Yes. XnView MP reads DICOM (.dcm, .dic, .dicom, .acr, .dc3) files natively on Windows, macOS and Linux, with no plugin required. Multi-frame series such as CT slices and MRI sequences are accessible page by page through the Pages panel.

Can XnView export DICOM to JPEG, PNG or TIFF?

Yes. Open the .dcm file in XnView MP, then File > Save as and pick JPEG, PNG or TIFF as the output format. For batch conversion of an entire study, use XnConvert: drag the DICOM files in, choose the output format and click Convert. Note that XnView does not write DICOM — only read.

Is XnView a medical diagnostic tool?

No. XnView MP is a general-purpose image viewer that happens to read the DICOM format. It is not certified as a medical diagnostic device. For clinical interpretation, use a DICOM viewer cleared by your regulatory authority (FDA, CE Medical Device, etc.) on a calibrated medical display.

Does XnView read DICOM metadata (patient, modality, study)?

XnView reads the standard DICOM tags embedded in the file (modality, study description, date) and shows them in the Properties dialog. It does not provide a full DICOM tag browser like dedicated medical viewers.

How do I navigate a multi-frame DICOM (CT, MRI)?

Open the DICOM file in XnView MP. The page navigation toolbar at the top of the viewer and the Page Up / Page Down keys let you step through frames; the Pages side panel shows every frame as a thumbnail for quick navigation.

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