Anonymization: what it is and how it applies to patient photos
Quick facts
- Definition
- Processing that makes it impossible to identify a person from the data, by reasonable means.
- Basis
- Concept provided for in the LGPD (Brazilian Law 13,709/2018).
- Legal effect
- Truly anonymized data stops being personal data.
- Face photo
- Rarely anonymized just with a bar or a crop.
- Alternative
- Obtain specific consent for the use of the image.
Anonymization is the set of techniques that make it impossible, by reasonable means, to identify the person the data refers to. The LGPD (Brazil's data protection law) defines the concept: anonymized data is not considered personal data, as long as the process cannot be reversed with reasonable effort.
Why is it hard to anonymize a face photo?
The face is a person's main identifier. A bar over the eyes, a crop or a blur is not always enough: the shape of the face, a scar, a tattoo, the hair and even the setting can lead to identification. In addition, a facial photo can be treated as biometric data when used to recognize people, which places it among sensitive data.
When does this matter in the clinic?
| Situation | What to consider |
|---|---|
| Photo in the patient record | Legal basis of health protection, confidentiality and retention |
| Photo on social media or a website | Specific consent and the rules of your professional council |
| Photo in a study or class | Consent or effective anonymization |
| Sharing with another professional | Purpose and necessity, with care |
The use of images in advertising follows what each professional council and CONAR (Brazil's advertising self-regulation council) allow, and that is the subject of the image use agreement and the legal basis under the LGPD.
How does Harmy relate to this?
Good practice: never present the projection as if it were a result, and keep informed consent with the explicit purpose of each use.
Also known as: de-identification (a related concept), data dissociation.
Frequently asked questions
Does covering the patient's eyes in the photo anonymize the image?
Generally, no. The face, tattoos, scars, setting and context can identify the person. If there is a reasonable risk of identification, the image is still personal data and requires a legal basis.