Dental scan viewer: DICOM, CT and panoramic in the browser

That is normal: DICOM files often have no extension at all and usually sit inside a folder named something like DICOM, IMAGES, DATA or ST0/SE0. Select the contents of such a folder wholesale — the tool works out that they are scans from the file itself, not from the name. A file called DICOMDIR is a table of contents rather than a scan, and you can ignore it: the tool mentions it separately and carries on with the rest.

Inside DICOM, pixels can be written in several ways, and two of them — JPEG 2000 and JPEG-LS — we do not read yet. The tool names the specific transfer syntax so that it can be checked and explained at the clinic. There are two ways round it: use the program that usually sits on the same disc, or ask the clinic for an export in a common format, which most machines can produce.

Probably not. Medical images contain far more brightness levels than a screen can show, and which range to display is set separately — that is called windowing. The file carries a recommended window, but it does not always suit. Press “Auto-adjust”: the tool computes the window from the scan itself, discarding the extreme percentiles that are usually taken up by the black border and the machine’s label.

It is not worth trying to draw conclusions. Caries appears on a scan as a darkening, but so do the shadow of a neighboring tooth, overlap from incorrect positioning, an old filling of certain materials, and simple anatomical variation. A clinician reads the scan together with an examination and knows where to look. The point of this tool is different: to see your own scan, understand which tooth is being discussed, measure a distance and pass the image to a second opinion without sending the whole disc.

Because automatic alignment would be a guess. Panoramic images differ in magnification, tilt and positioning between machines and between patients, and an alignment error of one tooth means a wrong number — exactly the mistake people come here to fix. Manual adjustment takes five seconds and you can see the result with your own eyes.

On tomography slices, yes — the pixel size is recorded and the measurement matches reality. On a panoramic image it is more complicated: a panoramic radiograph is made with a moving slit and has its own magnification, which differs across the jaw, typically by 10–30 per cent. So millimeters from a panoramic image are a guide, and for implant planning a dentist measures from the tomography.