The short answer: on a Mac, start with Weasis if you need a free open-source viewer that comes as a native installer for both Apple Silicon and Intel. Pick Horos if you want the classic OsiriX-style Mac interface and database. Use OsiriX Lite for teaching and review only. MicroDicom does not run natively on macOS. Whichever you choose, none of these free viewers is a substitute for the certified software that came with your own CBCT unit.
For dentists, dental students, technicians and clinic IT staff who receive CBCT scans and X-rays on a MacBook or iMac. Status: Not tested yet. Facts come from the developers’ own pages and our verified program pages, checked on 16 October 2026. Prepared by the dentsoftpro editorial team.
The short list
| Program | Licence | Mac support | 3D / MPR | Clinical status |
|---|---|---|---|---|
| Weasis | Free, open source (EPL 2.0 / Apache 2.0) | PKG for Apple Silicon (macOS 12+) and Intel (macOS 11+), version 4.7.3 | MPR, volume rendering, MIP slabs | Not a certified medical device (CE or FDA), says the vendor |
| Horos | Free, open source (LGPL 3.0) | Apple Silicon build 4.0.1 for macOS 26 Tahoe; Intel build labelled 4.0.0 RC5 | Yes, OsiriX-style 2D and 3D tools | No statement on the download pages |
| OsiriX Lite | Shareware (conditionally free): demo of OsiriX MD | macOS 12 to 27, Intel and Apple Silicon | 3D MPR, curved MPR, 3D rendering at demo level | Not for primary diagnosis |
| 3D Slicer | Free, open source (BSD-style licence) | macOS 14 or later, Intel and Apple Silicon (per its documentation) | Full research toolset | Research software |
| MicroDicom | Free for non-commercial use | Not native: runs through Wine or CrossOver | 3D MPR and volume rendering since 2026.3 | Not for clinical use |
Weasis: the best all-round free choice
Weasis is a free, open-source DICOM viewer distributed under the EPL 2.0 and Apache 2.0 licences. Its macOS downloads are PKG installers: Weasis-4.7.3-aarch64.pkg for Apple Silicon (macOS 12 or higher) and Weasis-4.7.3-x86-64.pkg for Intel (macOS 11 or higher). Homebrew users can install it with brew install --cask weasis. The vendor lists 2D, MPR and 3D views including volume rendering and MIP slabs, calibrated measurements, and DICOMweb and DIMSE connections to a PACS. It reads files from a local folder, a USB drive or a DICOM CD, which matters for patient discs.
The vendor states that the open-source distribution is not a certified medical device (CE or FDA), so primary diagnostic use depends on your local regulations. Developer site: weasis.org.
Horos: OsiriX-style, free, with version caveats
Horos is a free open-source DICOM viewer for macOS under the LGPL 3.0 licence. Its home page presents version 4.0.1 for Apple Silicon and macOS 26 Tahoe. The download page lists an Intel build labelled 4.0.0 RC5 for macOS 10.11 or later and older 3.x builds, and its version labels are not fully consistent, so read the page carefully before choosing a file. For Apple Silicon problems, the project suggests replacing the HorosCloud plugin. The pages say nothing about FDA or CE status, so do not assume any. OsiriX is a trademark of Pixmeo. Developer site: horosproject.org.
Horos is the usual answer when OsiriX Lite hits its series limit, because the Lite limit does not apply to it.
OsiriX Lite: a demo, good for learning
OsiriX Lite is the complete demo version of Pixmeo’s OsiriX MD. Pixmeo states that the software is not intended for primary diagnostic use, only for scientific usage. Per our verified program page, it stamps images “NOT FOR MEDICAL USAGE” and opens about 800 images per series, which a thin-slice CBCT can exceed. Its curved MPR is handy for showing the dental arch in teaching. Details of every limit are in OsiriX Lite limitations.
3D Slicer and MITK: research tools
3D Slicer is free, open-source software under a BSD-style licence with no restrictions on use. Its documentation lists macOS Sonoma (14) or later on both Intel and Apple Silicon. Dental and craniofacial modules, such as CBCT superimposition and landmark measurement, come through SlicerCMF, which is installed from the Extension Manager and has been dormant since 2022. Treat Slicer as research software. MITK (BSD, Windows, macOS and Linux) is another research workbench for segmentation and STL export. Neither is a quick viewer for a patient disc; see our open-source CBCT imaging platforms overview.
MicroDicom and 3DimViewer on a Mac
MicroDicom is a Windows program. Its FAQ says it runs on macOS with Wine or CrossOver, which means a translation layer rather than a native app. It is free for non-commercial use only, and the vendor says it must not be used for clinical purposes. For the Windows workflow, read how to open a dental CBCT disc in MicroDicom.
3DimViewer offered a macOS package, but the last official release is 3.1.1 from January 2017. We do not recommend it as a main viewer.
Which one should you use
- A free viewer for patient discs and referral scans, on any Mac: Weasis.
- You prefer the OsiriX layout and have a recent Mac: Horos, after checking which build matches your macOS.
- Teaching, demonstrations, curved MPR practice: OsiriX Lite.
- Segmentation, 3D models, research: 3D Slicer or MITK.
- A diagnostic read: the certified software from your CBCT vendor, or a certified product such as OsiriX MD.
Before sending a case to a colleague, see our guide to anonymising DICOM files. For the full list, including Windows and Linux, use our hub of free DICOM viewers for dental use, and for the two names dentists compare most, OsiriX Lite vs MicroDicom.
Limitations
We have not installed or run these programs on a Mac, so speed, memory use and how each handles a large CBCT are Not tested yet. Version numbers and download labels change; confirm them on the developer’s page before installing. This article is not legal or regulatory advice.
FAQ
Is there a free DICOM viewer for Mac?
Yes. Weasis and Horos are free and open source, and OsiriX Lite is a free demo of a commercial product. 3D Slicer is free too, but it is research software.
Is OsiriX Lite free for Mac?
Downloading it costs nothing, but it is the demo of OsiriX MD, limited and not for primary diagnosis. We list it as shareware (conditionally free).
Does MicroDicom work on Mac?
Not natively. The vendor says it runs on macOS with Wine or CrossOver.
Which Mac viewer works on Apple Silicon?
Weasis publishes an Apple Silicon PKG, Horos lists an Apple Silicon build, OsiriX Lite supports Intel and Apple Silicon, and 3D Slicer supports both.
Can I open a dental CBCT disc on a MacBook?
Weasis can read files from a DICOM CD, a USB drive or a folder. A MacBook without a disc drive needs an external reader, or a copy of the disc contents on a USB stick.
Is a free DICOM viewer allowed for diagnosis?
Check each vendor’s statement. Weasis says its open-source build is not a certified medical device, OsiriX Lite says it is not for primary diagnosis, and MicroDicom says it is not for clinical use.
Last updated: 16 October 2026 · DentSoftPro editorial team. Licence, version and platform details are checked against each developer's official documentation; none of the tools listed here should be treated as a certified medical device unless its vendor says so.
