No. Everything runs in this browser tab on your own device. Engines are downloaded once and cached, but your files never leave your computer.

Can I use this for diagnosis?

No. It is a viewer for education and convenience, not a certified medical device.

Are my files uploaded?

No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.

Is it free? Are there limits or watermarks?

Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.

Does it work offline?

Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

Home / Image / DICOM Viewer

DICOM Viewer

View DICOM series, NIfTI and NRRD medical images with window and level, slice scrubbing and PNG export.

Free, no uploads, no sign-up. Runs 100% in your browser.

How DICOM Viewer works

DICOM files are parsed with dicom-parser, NIfTI with nifti-reader-js and NRRD with the three.js loader. Slices are sorted by instance number, rescaled to real units (such as Hounsfield units for CT) and shown with adjustable window and level. Nothing leaves your device.

Input: DCM, NII, NII.GZ, NRRD. Output: PNG, ZIP.

How to use DICOM Viewer

Drop a folder of DICOM files (select all of them) or a NIfTI or NRRD file.
Drag on the image to change window and level, scroll to move between slices.
Use CT presets such as lung or bone.
Save the current slice or all slices as PNG.

Tips

Patient details are blurred until you choose to show them. Exported PNGs contain no patient data.
Uncompressed and baseline JPEG DICOM are supported. Other compressed transfer syntaxes are not yet.

DICOM Viewer FAQ

Is my file uploaded?: No. Everything runs in this browser tab on your own device. Engines are downloaded once and cached, but your files never leave your computer.
Can I use this for diagnosis?: No. It is a viewer for education and convenience, not a certified medical device.
Are my files uploaded?: No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
Is it free? Are there limits or watermarks?: Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
Does it work offline?: Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

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