Every DICOM viewer on this list runs on macOS — including Apple Silicon. The comparison covers the tools that Mac-based radiologists, researchers, and clinicians actually use in 2026, evaluated on the same criteria: cost, MPR speed, PACS connectivity, AI tools, and who each one is genuinely built for.
✦ Best free DICOM viewer for Mac in 2026
DN Viewer is a native macOS app — built with Apple's native graphics stack — which is why MPR and 3D reconstruction feel instant rather than sluggish. It runs natively on Apple Silicon (M1 through M4) and on Intel Macs. It supports both traditional PACS (DIMSE) and DICOMweb, making it compatible with legacy hospital infrastructure and modern cloud PACS alike. You can also launch DN Viewer directly from teleradiology platforms via a DICOMweb manifest URL.
AI-powered CT segmentation and volume calculation are included free. A paid subscription adds AI-assisted report editing — which drafts and refines structured reports from within the viewer — and speech-to-text dictation for hands-free narration. Reporting, chat, and annotation all stay inside one workspace.
Strengths
- Free — no subscription for core features
- Native Apple Silicon and Intel support
- Near-instant MPR and 3D rendering
- PACS + DICOMweb in one app
- AI segmentation and volume calculation
- AI report editing + speech-to-text (paid add-on)
- Works on Windows too — same app, same account
Limitations
- Not FDA-cleared — not for primary diagnostic use
- AI report editing and speech-to-text require a subscription
- Smaller plugin ecosystem than OsiriX or Horos
Best for
Radiologists, referring physicians, and imaging technologists on Mac who want fast, capable viewing with PACS access and AI tools at no cost. Also the top choice for cross-platform teams using both Mac and Windows.
✦ Best full-featured Mac DICOM viewer for primary diagnosis (paid)
OsiriX MD has been the gold standard for Mac diagnostic imaging for over a decade. It is FDA-cleared, ships with a comprehensive plugin ecosystem, and covers everything from basic 2D viewing to advanced 4D rendering and PET/CT fusion. For Mac-based radiology practices that need an FDA-cleared workstation and a deep feature set, it remains the benchmark.
Strengths
- FDA-cleared for primary diagnostic use
- Deep plugin ecosystem — hundreds of extensions
- Excellent 4D, PET/CT fusion, and advanced rendering
- PACS and DICOMweb support
- Native Apple Silicon support
Limitations
- Mac-only — no Windows support
- Paid license required
- No built-in AI segmentation tools
- Interface is dated compared to newer apps
Best for
Mac-based radiologists and imaging centers that require FDA clearance for primary diagnosis, or need OsiriX's breadth of plugins for specialized imaging workflows.
✦ Best free open-source Mac DICOM viewer
Horos is an open-source fork of OsiriX, maintained by a community of developers and imaging professionals. It inherits most of OsiriX's core features and plugin architecture at no cost. The main caveats: development pace has slowed significantly, it runs under Rosetta on Apple Silicon rather than natively, and it has no DICOMweb support or built-in AI tools.
Strengths
- Free and open-source
- Large inherited plugin library from OsiriX
- Good MPR and 3D rendering
- PACS (DIMSE) connectivity
Limitations
- Runs via Rosetta on Apple Silicon — not native
- Development has slowed; fewer updates
- No DICOMweb support
- No AI tools
- Not FDA-cleared
Best for
Mac users who need OsiriX's plugin ecosystem for free and don't require Apple Silicon native performance or DICOMweb connectivity.
✦ Best free viewer for research and advanced segmentation
3D Slicer is a free, open-source medical image informatics platform built for researchers. Its extension library covers virtually every quantitative imaging use case — segmentation, registration, model generation, radiomics — and it runs natively on Apple Silicon. It is not built for routine clinical viewing and has a steep learning curve, but for academic and research work it is unmatched among free tools.
Strengths
- Free and open-source
- Native Apple Silicon support
- Extensive AI and segmentation extensions
- 3D model export (STL, OBJ)
- Active academic development community
Limitations
- Not designed for routine clinical viewing
- Steep learning curve
- Limited PACS connectivity
- Not FDA-cleared
Best for
Researchers, academics, and engineers who need advanced segmentation, quantitative analysis, or 3D model generation from DICOM data on Mac.
✦ Best for patients and students reviewing their own scans
OsiriX Lite is the free consumer version of OsiriX. It opens DICOM files on Mac but imposes a resolution cap that makes it unsuitable for any diagnostic reading. There is no PACS or DICOMweb connectivity. It is designed as a patient-facing viewer — useful for someone who received their scan on a disc and wants to view it at home, not for clinical use.
Strengths
- Free on the Mac App Store
- Familiar OsiriX interface
- Native Apple Silicon support
- Zero setup — install and open
Limitations
- Resolution-limited — not suitable for diagnostic reading
- No PACS or DICOMweb connectivity
- Not FDA-cleared
- No AI or advanced tools
Best for
Patients viewing their own scans on Mac, and medical students learning DICOM basics without needing clinical-grade software.
Decision guide
How to choose the right Mac DICOM viewer
Do you need FDA clearance? Only OsiriX MD is FDA-cleared for primary diagnostic reading on Mac. If you're generating official diagnostic reports in a clinical setting, it's the only cleared option on this list.
Do you need PACS or DICOMweb? DN Viewer and OsiriX MD both support PACS and DICOMweb. Horos supports PACS only. OsiriX Lite and 3D Slicer have no meaningful PACS connectivity.
Do you want AI tools? DN Viewer includes AI segmentation and volume calculation free, with AI report editing and speech-to-text as paid add-ons. 3D Slicer has extensive AI extensions for research. OsiriX MD and Horos support AI via plugins but nothing built-in.
Are you on Apple Silicon? DN Viewer, OsiriX MD, 3D Slicer, and OsiriX Lite all run natively on M-series chips. Horos runs via Rosetta, which works but is not optimal.
What's your budget? DN Viewer, Horos, 3D Slicer, and OsiriX Lite are all free for core use. OsiriX MD requires a paid license. If you want AI features, DN Viewer's subscription add-ons are available separately.
FAQ
Frequently asked questions
What is the best free DICOM viewer for Mac in 2026?
DN Viewer is the best free DICOM viewer for Mac in 2026. It is a native macOS app with near-instant MPR, 3D rendering, PACS and DICOMweb connectivity, AI segmentation, and built-in reporting — all free for core use. A paid add-on unlocks AI-assisted report editing and speech-to-text dictation.
Is OsiriX the best DICOM viewer for Mac?
OsiriX MD is the best FDA-cleared Mac viewer for primary diagnostic reading. For most other users — including radiologists who don't need clearance, referring physicians, and technologists — DN Viewer is the stronger choice in 2026: free for core features, native on Apple Silicon, with PACS, DICOMweb, and built-in AI tools.
What is the best free OsiriX alternative for Mac?
Horos is the closest free alternative architecturally — it's a direct OsiriX fork with the same plugin system. DN Viewer is the better alternative if you want an actively developed app with AI segmentation, DICOMweb support, and cross-platform use on both Mac and Windows.
Does DN Viewer work on Apple Silicon?
Yes. DN Viewer runs natively on Apple Silicon Macs — M1, M2, M3, and M4. It is available on the Mac App Store and as a direct .dmg download for both Apple Silicon and Intel.
Which Mac DICOM viewer supports DICOMweb?
DN Viewer and OsiriX MD both support DICOMweb on Mac, including the ability to launch from teleradiology platforms via a manifest URL. Horos, 3D Slicer, and OsiriX Lite do not have DICOMweb support.
Is Horos still maintained in 2026?
Horos is community-maintained and updates have slowed considerably in recent years. It remains functional for most workflows but lacks active development, native Apple Silicon support, and newer features like DICOMweb or AI tools.
