The short answer: open the study in a viewer that has an anonymise command, run it on a copy of the files, then open the result and check it before anything leaves the clinic. In MicroDicom, the command is File > Anonymize for the images you have open and File > Batch > Anonymize for a whole folder. This guide shows the steps, what a header-only clean-up misses, and which free viewers can and cannot do the job.
It is written for dentists, dental technicians and clinic IT staff who need to send a CBCT or a set of DICOM images to a colleague, a lab, a supplier or a student, and for researchers who handle their own cases. It is not legal advice. Privacy rules differ by country and by purpose, so involve whoever is responsible for privacy in your practice before you share patient data.
What “anonymised” means in a DICOM file
A DICOM file is not just pixels. The header carries the patient’s name, ID, birth date, the study date, the referring physician, the institution, the scanner and many other fields, and the same file may also hold private tags that a manufacturer added. The DICOM standard describes a “Basic Application Level Confidentiality Profile” that sets out which attributes must be removed or replaced when you make a de-identified copy. The standard itself says that following this profile does not guarantee confidentiality, so a broader de-identification process is still required.
Three points from the standard matter in a dental office:
- Burned-in text. Identifying text can be part of the image itself, for example a name stamped on a panoramic image or a screenshot saved as DICOM. The standard handles this through a separate “Clean Pixel Data Option”, and it requires the stored pixel values to change. Cleaning the header does not do it.
- Private attributes. The Basic Profile removes them, and the standard warns that identifying information can still hide in private data.
- Dates and identifiers. Study dates and unique identifiers can also point back to a person. There are options that deliberately keep some of them, for example for follow-up studies, and the standard notes that keeping information the profile would remove raises the risk of re-identification.
Which viewer can anonymise
| Program | Anonymise? | Licence | Platform | Status |
|---|---|---|---|---|
| MicroDicom | Yes: single study and batch folder | Free for non-commercial use; commercial licence from the vendor | Windows (Mac via Wine package) | Current, version 2026.3 |
| OsiriX Lite | Vendor lists anonymisation in the OsiriX feature sheet; check it in the Lite build you install | Shareware (conditionally free), not for primary diagnosis | macOS | Current, 14.2.x line |
| Aeskulap | Not listed on the project’s pages | Free, open source (GPL) | Linux | Discontinued; last stable release 2006 |
Anonymise a study in MicroDicom
MicroDicom is a Windows viewer from MicroDicom Ltd in Sofia, Bulgaria. It is free for personal and educational use. The vendor states that it has no CE mark or FDA approval and must not be used for clinical purposes, which is fine for de-identifying a copy but worth knowing.
One study
- Copy the original study to a working folder. Never anonymise the only copy.
- Open the images in MicroDicom.
- Choose File > Anonymize and pick the option for the current images.
- Select an empty output folder when the folder dialog appears.
- Wait for the export to finish, then close the original study.
A whole folder
- Choose File > Batch > Anonymize.
- Select the source folder with the DICOM files.
- Select a different destination folder.
- Click Anonymize and wait for it to finish.
MicroDicom’s own tutorial page does not say whether pixel data is touched, so assume it is not and check the images yourself.
Check the result before you share it
- Open the output folder in the viewer, not the original, and look at the patient name and ID shown in the study list.
- Open the DICOM tag browser on one file from each series. Look at the patient name, patient ID, birth date, institution, physician and any comment fields.
- Scroll through the images and look at all four corners. Panoramic and cephalometric exports often carry text in the image itself.
- Check the file names and folder names. A folder called after the patient’s surname defeats the purpose.
- If the case needs to be matched to your own records, keep a private list that links the new study to the patient, stored separately from the files you send.
OsiriX Lite on a Mac
Pixmeo’s technical sheet for OsiriX describes anonymisation of studies for research or teaching, and its support site has an article on the topic. The article was not readable when this page was checked, so we do not give menu steps here. Install the build you plan to use and test the command on a dummy study first. Keep the Lite limits in mind: images carry a “NOT FOR MEDICAL USAGE” stamp, series size is limited, and the edition is not for primary diagnosis. Read our OsiriX Lite page for the details.
Why Aeskulap is not the answer
Aeskulap is an open-source Linux viewer and PACS query client. Its feature list covers viewing, windowing and query/retrieve, and does not mention anonymisation. The project is discontinued, so do not expect a new feature. Use it, if at all, to look at images, and de-identify them elsewhere.
Limitations of viewer-based anonymisation
- A viewer’s anonymise command is a general-purpose tool. It is not proof of compliance with any privacy law.
- Burned-in text, odd private tags and identifying file names need a manual check.
- Free MicroDicom use is limited to non-commercial use. Sharing a patient case from a working practice is professional use, so a practice should plan on the vendor’s commercial licence.
- Uploading patient studies to an online anonymiser sends the identified data to a third party before it is cleaned. Do not do that unless your privacy officer has approved the service.
- Scripts can anonymise in bulk, but they must be tested against the standard’s profile and your own data, and that work is beyond this guide.
Which route to choose
- Windows PC, a few cases: MicroDicom, single or batch, then the checklist above.
- Mac: test the anonymise command in OsiriX Lite, or see OsiriX Lite vs MicroDicom if you are choosing between the two.
- Regular sharing or research programmes: agree a written procedure with your privacy officer, including who checks the output.
For a wider comparison of viewers, see our guide to free DICOM viewers for dental use.
FAQ
How do I anonymise DICOM files?
Make a copy of the files, run the anonymise command of a DICOM viewer on the copy, and check the result. In MicroDicom use File > Anonymize or File > Batch > Anonymize.
Is there a free DICOM anonymizer for Windows?
MicroDicom is a free Windows viewer with an anonymise function, for personal and educational use. Professional use needs the vendor’s commercial licence.
Can I anonymise DICOM images online?
Technically yes, but you would upload identified patient data to a third party first. Do that only with approval from whoever handles privacy in your practice. A local viewer keeps the data on your own computer.
Does anonymising remove text burned into the image?
Not by default. The DICOM standard treats burned-in text as a pixel-level problem that needs its own clean-up, so look at every image corner after you anonymise.
What is the difference between anonymised and de-identified?
The words are often used for the same thing. The DICOM standard speaks of de-identification and says that even a conforming result does not guarantee confidentiality.
How do I check that a DICOM file is anonymised?
Open the result, not the original, and read the tags in the tag browser. Check name, ID, birth date, institution and physician fields, the image corners and the file names.
Last updated: 11 October 2026 · DentSoftPro editorial team. Licence, version and platform details are checked against each developer's official documentation; none of the tools listed here should be treated as a certified medical device unless its vendor says so.
