What is on an imaging CD
The disc from a CT, MRI, X-ray or ultrasound visit is not a folder of photos. It normally contains:
- DICOMDIR, an index file with no extension that lists the patient, the study and every image on the disc. It is not an image itself.
- A folder such as DICOM/, IMAGES/ or a nest of numbered folders holding the actual image files. The files usually have no extension, or a numeric name, or sometimes .dcm.
- Often a bundled Windows viewer (an .exe and its support files, sometimes an autorun). It will not run on a Mac, a Chromebook or a work PC where software installation is blocked.
- Sometimes the written report as a PDF, and sometimes nothing but the images.
Everything you need to see the images is in the DICOM folder. The bundled program is a convenience for Windows users, not a requirement.
Open the disc in a browser, step by step
The viewer below is ours (MiniPACS makes it), it is free, and it works without an account. The files stay on your computer.
Insert the disc, or copy its folder. If the computer has no drive, copy the whole disc onto a USB stick from a machine that does, or use the download link if the imaging center offered one. Keep the folder structure as it is.
Open minipacs.net/free-dicom-viewer/ in any modern browser.
Drag the whole folder (the disc root, or the DICOM folder) into the page, not single files. The viewer walks every file, skips the DICOMDIR index and other non-image files automatically, and groups the images it finds by series. A ZIP of the folder works too.
Scroll the slices. Studies with several series are grouped and you switch between them with one click; scroll or drag to move through the slices of a series.
Adjust the window. Drag to change brightness and contrast (window and level) so bone, soft tissue or lung shows the way you want to see it.
Export a PNG for a referral. Set the window and press export: the current slice is saved as a PNG with your window applied, fine for a message to a clinician. It is a picture of one slice, not the study; see the second-opinion note below.
Troubleshooting
The disc reads, but nothing shows
- Encrypted or password-protected disc. Some centers wrap the images in an encrypted container that only their bundled program opens. There is no DICOM folder to drag. Ask the center for a plain DICOM export or a download link.
- The disc holds JPEG or PDF exports, not DICOM. Those open in any photo or PDF app, but they are pictures, not the study. If a clinician needs the real images, ask for a DICOM export.
- Compressed images. Discs are often compressed. The viewer decodes the JPEG family, JPEG-LS, JPEG 2000, RLE and deflated files in the browser; the exact coverage is in the viewer decode matrix. The few encodings it does not handle (JPEG Extended 12-bit, HTJ2K, MPEG video) are named in the notes under the image, with a count, so you know whether to look for a different file or a different tool.
- Only the index or a report was dragged in. A DICOMDIR, a structured report or a dose sheet carries no pixels. Drag the whole folder so the image files come along.
The disc only has an .exe
Look again: the images are almost always in a folder next to it, often named DICOM, IMAGES or a string of digits. Open that folder and drag it in. If the disc truly contains only a program and an encrypted data file, the images are locked inside it; ask the imaging center for a plain DICOM copy.
Mac or laptop without a disc drive
Copy the disc to a USB drive on any computer that has a drive (a library, an office, the imaging center's front desk), then open the USB folder as above. Better still, ask the imaging center whether they offer a download link or a patient portal instead of a disc; many do, and that copy is easier to keep and to pass on.
The images are needed for a second opinion
Ask the imaging center for a DICOM export, or ask them to send the study directly to the receiving practice, rather than printed films or JPEG screenshots. The reading radiologist works from the original slices at full resolution with the original measurements; a picture of one slice cannot replace that. The ways studies actually move between facilities are covered in medical image sharing.
Not for diagnosis
The browser viewer is a review and education tool, not a medical device. It has no display calibration, no audit trail and no reporting workflow. The reading radiologist's report is the clinical document; if something on the images worries you, ask your clinician rather than reading the scan yourself.
Related tools and guides
- Free DICOM viewer: the in-browser viewer used in the steps above.
- Convert DICOM to JPEG or PDF: every safe way, and when a converted file is the wrong thing to send.
- Viewer decode matrix: which free viewers open which compressed discs.
- Medical image sharing: how studies move between physicians, patients and facilities.
- All free DICOM tools: the hub for the viewer, the converter guide and the reference data.
For imaging centers that hand out these discs: MiniPACS is a standards-based DICOM archive and server, and any scan opens in any browser in about 0.6 seconds with nothing installed.
FAQ
Can I open a DICOM CD on a Mac?
Yes. The Windows viewer bundled on the disc will not run, but the images themselves are standard DICOM files. Copy the disc folder to the Mac, open the free browser viewer at minipacs.net/free-dicom-viewer/ and drag the whole folder into the page. The same works on a Chromebook, a Linux machine or a locked-down office PC where you cannot install anything.
Why will the viewer on the disc not run?
Most imaging centers burn a small Windows program next to the images. It needs Windows, sometimes an older version, and often administrator rights to start. On a Mac or Chromebook it is just a file that does nothing, and on a managed work computer it is usually blocked. Ignore it: the images are in a folder next to it and open fine without it.
Is it safe to upload my scans to a website?
With the browser viewer linked on this page nothing is uploaded: the files are parsed by JavaScript on your own device and thrown away when you close the tab, which you can verify in the browser's network panel. Many other online viewers upload the study to their server first. Before putting your scans into any other website, check whether it uploads.
Can I email the images to my doctor?
A single exported PNG is fine for a quick question, but it is a picture of one slice with one window setting, not the study. For a second opinion or a referral, ask the imaging center to send the DICOM study directly to the receiving practice, or ask for a DICOM export you can hand over. Printed films and JPEG screenshots lose the information a radiologist needs.
How do I get a copy of my images?
Ask the imaging center or hospital medical records department for a copy of your study in DICOM format. Many centers hand out a disc or USB drive; some offer a download link or a patient portal instead of a disc, which is easier if your computer has no drive. The written report is a separate document and is usually available faster than the images.