A radiology department deals in two quite different kinds of file, and only one of them opens in a free web viewer. It is worth being exact about which, because the difference is the whole point of this page.
The short version
DICOM does not open on Doconut.app. .dcm and .ima are deliberately not on the
list of accepted extensions, on this site or on OnlineDocumentViewer.com. If you have a
study straight off a modality or out of a PACS, this is not the tool, and no amount of
renaming the file will change that.
Everything downstream of it does open. The report, the scanned referral, the images somebody exported to send to a colleague:
- Scanned PDFs of radiology reports, up to 25 MB.
- TIFF scans, including multi-page ones, up to 25 MB. This is the common format for a document that came from a scanner or a fax gateway.
- PNG and JPEG exports of X-rays, CT slices and ultrasound stills, up to 25 MB.
- SVG for technical and molecular diagrams.
- Word and Excel for the reports and worklists around them, up to 15 MB and 20 MB.
Drop one on Doconut.app and it renders in the browser. Free, no account, and deleted from our servers when you close the tab.
Why DICOM is left out
DICOM is not really an image format; it is an image plus a patient. A .dcm file carries
the pixel data together with name, date of birth, accession number, referring physician
and a long tail of other identifying tags. A general-purpose public upload endpoint is the
wrong place for that, and leaving the format out is a clearer safeguard than any promise
we could make about handling it carefully.
The format is supported in the Doconut SDK, as a separately licensed DICOM plugin, for
exactly the situation where it belongs: rendering inside a hospital's own application, on
the hospital's own servers, behind the hospital's own access controls. That is the
difference between 75 extensions in the SDK and 73 on the free viewers — the two missing
are .dcm and .ima.
What the viewer does with an image once it opens
- It renders, it does not diagnose. This is a document viewer. It is not a diagnostic workstation, it is not a medical device, and nothing here is cleared for primary reading. Use it to look at a file, not to report on one.
- Zoom and page navigation, which is what a multi-page TIFF scan needs.
- Colour handling: in the vector and raw image viewer, embedded ICC profiles are applied, and a photograph's EXIF sits beside the image.
- Print with Ctrl+P, exactly as the pages render on screen.
There is no measurement tool, no windowing, no annotation and no export. A viewer draws the file; it does not write a new one.
What happens to the file
The upload runs over HTTPS. The file is rendered in a temporary session tied to your browser, and deleted from our servers when that session ends. There is no account, so there is nothing it could be filed under and nothing to come back to later.
Be equally clear about what that is not. We hold no HIPAA attestation, no ISO 27001 and no SOC 2. Doconut.app is a free public tool, and no free public tool should be handling identifiable patient data. If a document has a patient's name on it, it belongs inside your own systems — which is the argument for the SDK, where the file never leaves your network, rather than for this site.
Where this is genuinely useful
- A GP or a patient has been sent a report as a PDF and has nothing that opens it well.
- A researcher has exported figures as TIFF or SVG and wants to check one on a machine without the original software.
- Somebody needs to read a scanned referral on a phone.
- A developer is evaluating rendering quality before licensing the SDK, and wants to see what a real scan looks like coming out of the same engine.
If you need this inside your own system
That is the Doconut SDK: the same .NET rendering engine, installed in your environment, with DICOM available as a licensed plugin alongside Annotation, Converter and Search. Nothing leaves your servers, and the compliance boundary stays where your compliance people drew it.
For everything else — the report, the scan, the exported still — start at Doconut.app.