Breast cancer is diagnosed by imaging at a non-palpable stage in more than half of all cases. Surgical removal requires preoperative guidance. Generally, preoperative guidance is performed using a metal guide under local anaesthetic and radiological control. This type of guidance has several limitations. For the patient, it can be painful and traumatic. The procedure involves two departments: radiology and the operating theatre, which poses logistical constraints. What's more, between 10% and 40% of patients require repeat surgery for unhealthy margins, raising the question of the effectiveness of the tracking procedure. The investigators propose to develop a non-invasive intraoperative guidance system: Augmented Reality, which will provide a 3D vision with virtual transparency of the breast during surgery, thanks to real-time fusion of preoperative imaging with video from a camera located in the operating room. The process is illustrated below.

Illustration of the general principle of the augmented reality system for locating non-palpable breast lesions. The images above represent a preliminary test carried out on the computer outside the operating room. This is an initial research prototype which has not yet been validated and is not suitable for routine use.

Inclusion Criteria:

• Major women
• Requiring conservative surgical management of a subclinical cancerous breast lesion (not palpable), the histology of which has been previously proven by anatomopathology;
• Having a breast MRI indication at the time of the breast assessment performed at the Centre Jean Perrin
• Ability to give informed consent to participate in the study,
• Membership of a social security scheme

Exclusion Criteria:

• Patients with breast neoplasia during pregnancy;
• Persons deprived of their liberty or under guardianship or incapable of giving consent;
• Refusal to participate.