The study design concerns all patients diagnosed witha singular brain metastasis who underwent stereotactic radiosurgery/radiotherapy between January 2010 and December 2022

The study will include patients of both sexes diagnosed with single brain metastases who underwent radiosurgical/stereotactic treatment. Attention will be paid to data related to local control, potential recurrence, and/or radionecrosis. Once a sufficient number of treated patients is reached, the feasibility of a radiomic feature analysis will be assessed in order to identify potential correlations and/or predictive values for treatment response or radionecrosis. If the sample size is adequate, participating centers will be asked to share pre- and post-RT MRI (brain MRI with contrast using thin slices) and treatment volumes for radiomic evaluation.

Inclusion Criteria:

• Age ≥ 18 years
• Treatment with SRS/SRT techniques for a single secondary brain lesion
• Availability of pre-RT brain MRI with contrast (1mm slice thickness)
• Availability of CT simulation imaging for treatment
• Availability of relevant clinical data in the medical record for the study's objectives
• Follow-up of at least 6 months after the completion of SRS or SRT
• Follow-up evaluation through brain MRI

Exclusion Criteria:

• Age under 18 years
• Lack of clinical/radiological data for the patient
• Unavailability of the required imaging
• Previous whole-brain radiotherapy treatment

The study design concerns all patients diagnosed with brain metastases who underwent stereotactic radiosurgery/radiotherapy between January 2010 and December 2022.