Best free DICOM viewer (for patients, not radiologists)
Clinical DICOM viewers are powerful and intimidating. If you just got a scan CD from your hospital and you want to see your own MRI, you don't need 50 measurement tools. You need something that opens the files, lets you scroll through slices, and doesn't ship your scan off to a server. Here's the honest shortlist.
Quick answer (3 steps)
- Decide whether you need install-free viewing on a borrowed computer — if yes, start with OpenMyScan in the browser.
- If you need measurement-grade tools, plan on installing Horos (Mac) or RadiAnt (Windows) instead.
- Avoid random "upload your MRI" sites when you only want local browsing — they copy data to someone else's cloud.
Shortlist (patient use)
- OpenMyScan (this site). Browser-based, runs on any modern computer, no install, no account, no upload. Free forever for viewing; optional Pro adds PNG export, ZIP share package, and compare-two-scans mode — see pricing for current rates. Made specifically for patients.
- Horos (macOS). Excellent open-source clinical viewer. Free but Mac-only and clinical-looking — measurement tools, fusion, etc. If you're a Mac user comfortable with professional software, it's great. Requires install.
- RadiAnt (Windows). Trial is free, full version paid. Fast, popular with radiologists.
- Weasis (cross-platform). Java-based, open-source. Runs on anything but needs Java, which most people don't have.
- OsiriX MD / Lite (macOS). One of the oldest clinical viewers, and the project Horos was originally forked from. Powerful, but the UI is dense.
Head-to-head for the patient use case
| Tool | Install needed? | Upload to server? | Patient-friendly UI? | Works on school/work PC? | Free for full viewing? |
|---|---|---|---|---|---|
| OpenMyScan | No | No | Yes | Yes | Yes |
| Horos (Mac) | Yes | No | Somewhat | No | Yes |
| RadiAnt (Windows) | Yes | No | Somewhat | Maybe | Trial only |
| Weasis | Yes (Java) | No | Clinical | Unlikely | Yes |
| OsiriX Lite | Yes | No | Dense | No | Yes (limited) |
| "Online uploader" sites | No | Yes | Varies | Yes | Varies |
Why not an "upload your DICOM here" site?
Any viewer that requires upload is storing your medical images on their servers — subject to their privacy policy, breach risk, and terms that can change. For a one-off "look at my own MRI" use case, the right default is a tool that opens files locally: OpenMyScan in your browser, or an installed viewer like Horos.
When you actually need a clinical viewer instead
If you want to measure a lesion in mm, do angle / Cobb-angle measurements, print DICOM at true scale for a physical therapist, or run advanced 3D reconstruction — use Horos / RadiAnt. OpenMyScan deliberately omits those to stay simple for non-technical users.
Common problems when picking software
- IT locked my work laptop
- Browser viewers avoid installers; if even those are blocked, use a personal device.
- I downloaded three apps and none open the CD
- Copy the DICOM folder off the disc first — many tools choke on read-only drives.
- A site promises "AI diagnosis"
- Walk away for casual browsing — automated reads are not a substitute for your doctor.
- I need HIPAA-covered sharing
- Use workflows your hospital approves; do not improvise with consumer cloud accounts.
Frequently asked questions
Is OpenMyScan really free forever?
Yes, viewing is free with no limits. Pro features (export, compare, share package) are optional.
Is OpenMyScan open-source?
The checkout and license server are commercial; the viewer runs fully client-side. No data leaves your device regardless.
What about online viewers like "Jack Imaging" or similar?
Those upload your DICOM to their cloud. They're fine for second-opinion workflows where you want to share with a specific doctor, but not for local viewing.
Does this work offline?
Yes, after the first successful load. OpenMyScan caches in your browser, so you can use it on a plane or without WiFi as long as the page loaded once. Your files stay local either way.