Updated October 24, 2026
On a Mac you don't need to install a DICOM viewer to look at a scan. Open this page in Safari, Chrome, Edge or Firefox, click Open a disc or folder… or Open files or a ZIP…, and MesDICOM shows the images in the browser tab — free, with nothing uploaded.
How do I open DICOM files on a Mac?
- A disc or USB stick: click Open a disc or folder… and choose the disc or stick in the Finder dialog, or drag its icon from the desktop onto this page.
- A folder or a ZIP: choose it with the buttons above, or drag it from Finder onto the page.
- Single files: choose them with Open files or a ZIP…. Files without a .dcm extension open too.
If the disc came with a Windows viewer program, ignore it. MesDICOM reads the images directly. More: opening a CT or MRI disc.
What can it do?
Scroll through series, adjust brightness and contrast with 30 window presets, zoom, rotate and flip, measure lengths and angles, play cine, look at a CT or MR series in three planes and in 3D, read every DICOM tag, and save an image as a PNG. Save to Library keeps a study in this browser for next time.
Web or app: which should I use on a Mac?
| MesDICOM on the web | MesDICOM for Mac | |
|---|---|---|
| Install | Nothing | From the App Store, macOS 14.6 or later |
| Price | Free | Free to download; MesDICOM Pro (subscription) for 3D, an unlimited library and more |
| Opens | DICOM files, folders, discs, ZIP | The same, plus RAR, 7-Zip and ISO in the app |
| Keeps studies | In this browser, when you save one | In the app's library |
| Also on | Any computer with a browser | iPhone and iPad, from the same App Store listing |
The web version is the quickest way to look at a scan once. The app suits you if you open scans often or receive RAR and ISO files.
How does it compare with other free Mac viewers?
- Horos is a free, open-source medical image viewer for the Mac (LGPL-3.0), installed as a desktop app.
- Weasis is free and open source and runs on macOS, Windows and Linux as a desktop application.
- Windows-only viewers such as RadiAnt and MicroDicom don't run natively on a Mac; their makers point to Wine or CrossOver.
MesDICOM on the web is for opening your own scans without installing anything.
MesDICOM is for viewing and reference only — not intended for diagnosis or treatment decisions.
