Differentiating radiation necrosis from tumor progression in patients with brain metastases has a major therapeutic and prognostic implications

Differentiating radiation necrosis from tumor progression in patients with brain metastases treated with radiotherapy is a major challenge in post-treatment management, as the therapeutic and prognostic implications differ substantially depending on whether the lesion represents radiation necrosis (surveillance, anti-angiogenic therapy) or tumor progression (re-initiation of local or systemic treatment).

In addition to brain MRI, amino acid PET imaging, including both static and dynamic acquisitions, is a key diagnostic tool for this purpose.

However, the added value of dynamic acquisitions remains uncertain, and the available evidence is limited to small patient series.

Inclusion Criteria:

• Patients who received a PET amino acid for differentiating radiation necrosis from progression of irradiated brain metastases,

Exclusion Criteria:

• Patients who refused the using of their data

All patients referred for amino acid PET imaging in the Nuclear Medicine Department of Nancy University Hospital for the differential diagnosis between radiation necrosis and brain tumor progression between November 1, 2018, and April 30, 2026.