# View your CT scan online, in your browser

> Open your CT scan in your browser: lung, bone and soft-tissue windows, three planes, 3D and measurements. From a disc, folder or ZIP. Free, nothing uploaded.

Open the CT disc, folder or ZIP from the hospital and look through it with the same windows radiology uses — lung, bone, soft tissue and more — in three planes and 3D. Free, no account, nothing uploaded.

Open your scans here: https://mesdicom.com/ct-scan-viewer/ — or at https://mesdicom.com/

You can open your CT scan online without installing anything: choose the disc, folder or ZIP with the buttons above and MesDICOM shows it in your browser. Your scans aren't uploaded to our servers — they're opened and processed on your computer.

## What are CT windows?

A CT image holds far more shades than a screen can show, measured in Hounsfield units (HU): air is about −1000, water 0, bone several hundred and more. A **window** picks which part of that range you see: its centre (level) and its width. A narrow window shows small differences in soft tissue; a wide one shows lungs or bone.

MesDICOM has 20 CT presets. Some of the common ones:

| Preset | Window centre / width (HU) | Shows |
|---|---|---|
| Lung | −600 / 1500 | Air-filled lung |
| Mediastinum | 50 / 350 | The middle of the chest |
| Abdomen | 40 / 350 | Abdominal organs |
| Soft Tissue | 50 / 400 | Muscle and fat |
| Bone | 300 / 1500 | Bone |
| Brain | 40 / 80 | Brain tissue |

Drag on the image to set any window yourself; double-click resets it.

## What can I do with my CT?

- **Scroll** through the slices with the mouse wheel or the slider, or play them as a movie.
- **Zoom, pan, rotate and flip**; orientation letters and a scale bar stay on the image.
- **Measure** lengths and angles.
- **Three planes (MPR):** axial, coronal and sagittal views of one series, linked by a crosshair.
- **3D:** five renderings — MIP, Bone, Soft Tissue, Lung and Surface — that you can turn and zoom.
- **DICOM Info:** study and series details and every DICOM tag, searchable.
- **Share Image:** the image on screen as a PNG, without the patient's name or date.
- **Save to Library:** keep the study in this browser to open it again later.

## How do I see my CT in 3D?

Open a series and switch to **3D**. MesDICOM builds a volume from the slices and renders it in your browser with WebGL 2, which most computers have. Choose a rendering, drag to turn, scroll to zoom. A thin-slice series gives the clearest result.

## How do I open the CT disc?

Insert it, click **Open a disc or folder…** and choose the disc drive itself — not DICOMDIR or the program on it. Details: [opening a CT or MRI disc](https://mesdicom.com/open-dicom-cd/).

MesDICOM is for viewing and reference only — not intended for diagnosis or treatment decisions.

## Questions

### Why does my CT look completely grey or completely white?

The window doesn't suit what you are looking at. Pick a preset such as Lung, Soft Tissue or Bone, or drag on the image to change brightness and contrast.

### Can MesDICOM tell me what my CT shows?

No. MesDICOM shows the images; it doesn't interpret them. The radiologist's report and your doctor explain the findings.

### Can I measure something on my CT?

Yes. Length and angle are measured in millimetres and degrees on the image, or in any of the three planes. Measurements on a study you save stay with it.

### Does it open CT from any hospital?

It opens standard DICOM CT images, uncompressed or compressed (JPEG, JPEG Lossless, JPEG-LS, JPEG 2000, RLE), which is what hospital discs and downloads hold.

## Related guides

- [MRI viewer](https://mesdicom.com/mri-viewer/index.html.md): View your MRI scan online, in your browser. Open the disc, folder or ZIP from the hospital, scroll every series, see three planes and 3D. Free, nothing uploaded.
- [Open a CT or MRI disc](https://mesdicom.com/open-dicom-cd/index.html.md): Got your scan on a CD or DVD from the hospital? Open the DICOM images in your browser on Windows or Mac. No viewer program, no upload, free.
- [DICOMDIR viewer](https://mesdicom.com/dicomdir-viewer/index.html.md): DICOMDIR is a disc's table of contents, not the images. Choose the whole disc or folder and MesDICOM opens the images it lists. Free, in your browser.

Updated October 24, 2026. For viewing and reference only — not intended for diagnosis or treatment decisions.