Weasis vs PortaDICOM
We recommend Weasis to people who ask us for a free portable viewer, so this comparison is not a hatchet job. Weasis is excellent at what it does. The question is whether what it does is what you need, and for cardiologists and clinicians who carry cases between sites, the answer often is not.
By the Hirovix product team · Published 4 Oct 2026 · Facts checked against the sources listed at the end
What Weasis is
Weasis is a free, open-source DICOM viewer with a long history and an active maintainer. Its FAQ confirms a portable archive that runs without installation or administrator rights, support for opening CD/DVD/USB media via DICOMDIR, MPR, and a broad general radiology toolset. It is cross-platform and distributed through its website, GitHub, the Microsoft Store and package managers.
Side by side
| Weasis | PortaDICOM | |
|---|---|---|
| Price | Free, open source | PortaDICOM pricing: one licence per 2 TB SSD, per-site licensing available; contact us for current pricing and a free demo on your own study. |
| Runs without install or admin rights | Yes (portable archive) | Yes (from its SSD) |
| Platforms | Windows, macOS, Linux | Windows; macOS and Linux on the roadmap |
| Cine XA playback | Yes | Yes, with adjustable frame rate and look-ahead cache |
| Calibrated cardiology toolset (% stenosis QCA, TIMI, AHA segments, pre/post-PCI) | Not offered | Yes (review-grade) |
| Case library that travels with the viewer | Local import per machine | 2 TB on the same drive, de-duplicated by SOP Instance UID, incremental backup |
| Licensing accountable to a device | Not applicable | One licence locked to one SSD |
| Vendor support | Community (GitHub, forums) | Hirovix, directly |
| Intended use | Per project documentation | Review and records only |
PortaDICOM is for review and records only; measurements are operator-confirmed estimates, not a primary diagnostic read.
Choose Weasis if
- You need a free general radiology viewer that runs anywhere without admin rights.
- You use a Mac or Linux machine.
- You are comfortable with community support and configuring the viewer yourself.
Choose PortaDICOM if
- You review coronary angiography and want calibrated % stenosis, TIMI counts, AHA segment tagging and pre/post-PCI comparison on any PC.
- You want your entire case history to travel with the viewer on one 2 TB drive, searchable, with a backup you control.
- Your hospital wants a licence it can account for on a specific device, and someone to call.
FAQ
Is Weasis really free for hospital use?
Yes. It is open source under a permissive licence and free for any use. Check the current licence on the project site if your institution requires it.
Does Weasis measure percent stenosis?
It offers general distance and ROI tools; it does not advertise a calibrated QCA toolset or TIMI frame counting.
Can I use both?
Many clinicians do: Weasis on a personal machine for general viewing, PortaDICOM on the SSD for cath-lab review and the travelling case library.
Related guides and comparisons
- ComparisonPortable RadiAnt, or RadiAnt without admin rights: what actually works
- ComparisonRadiAnt DICOM Viewer alternatives for Windows
- ComparisonMicroDicom alternatives
- ComparisonHoros for Windows: there is no PC version, so what do you use?
- ComparisonBrowser viewer, installed viewer, or a viewer on an SSD?
- GuideHow to open a DICOM CD on a Windows PC
Sources
Third-party facts on this page were checked on the date shown at the top. Vendors change prices and features; verify before you buy.
See PortaDICOM on your own scans
A free demo on one of your studies is the fastest way to know it fits — no install, no obligation.