The purpose of this study is to determine if the stereotactic, MR guided, laser interstitial thermal therapy treatment technique can be safety and efficiently used for human brain metastasis and primary brain tumors.

This new "minimally invasive" technique has been tested so far, with success, on animal brain tumor models and on human liver metastasis.

The main purpose of this study is to determine if the stereotactic, MR guided, laser interstitial thermal therapy treatment technique can be safety and efficiently used for the human brain metastasis and primary brain tumors.

As secondary objectives for this clinical study, the following are to be explored:

• Eventual evaluation of the eventual mid and long term post-intervention complications,
• Evaluate the contra indication for the technique,
• Evaluate and optimize clinical and logistic intervention protocols,
• Evaluate the mean duration for the procedure,
• Evaluate the mean cost for the procedure

The clinical trial will include a statistical sample of 12-18 treatments and will run over a period of 18 months. The inclusion period will be for 6 months and the patients will be followed up during 12 months post intervention.

The clinical trial will be performed at the Lariboisiere University Hospital of Paris and the patients will be coming from all the Assistance Publique de Paris ( APHP ) hospitals

Inclusion Criteria:

• Patients 18 years of age or older
• Patients with brain metastasis located in the brain hemispheres
• Patient with a brain metastasis smaller or equal to 4 cm in diameter
• Patient with primary brain tumor smaller or equal to 4 cm in diameter
• Patient previously treated with other therapeutic techniques ( radio-therapy, chemotherapy, immunotherapy) which have failed.

Exclusion Criteria:

• Patients less than 18 years old,
• Patients presenting contra indication for MRI studies
• Patient for which the primary cancer is melanoma or kidney tumors
• Patients having a mean life duration longer than 3 months (due to the primary cancer)