The objectives of this registry study are to evaluate real-world clinical outcomes and patient reported outcomes that measure the effectiveness and safety of STaRT.

Patients (N=600) with surgically resected (R) brain tumors of any pathology who have undergone STaRT are eligible. Data collected will include local control, overall survival, QOL, neurocognition, functional decline, and surgical and radiation associated AE's. Data will be collected at 1, 3, 6, 9,12, 18 and 24 months, then every 6 months through 5 years. RESULT: Data will be used to benchmark clinical outcomes of STaRT therapy and allow for comparisons to existing standard-of-care treatments. This will be the first observational registry study of R+STaRT, delivered by Cs-131 sources in permanently implanted resorbable collagen tile carriers. The outcome measures captured will allow for evaluation of the potential risks and benefits of this treatment approach for patients in a real-world setting.

Inclusion Criteria:

1. Patients who undergo maximum safe resection of intracranial neoplasm(s) AND implantation of GammaTiles.
2. Willing and able to provide informed consent and to participate in all evaluations.

Exclusion Criteria:

1. Inability to undergo pre-operative and post-operative imaging for disease and implant assessment.
2. Major medical or psychiatric illness, which, in the investigator's opinion would prevent completion of treatment, ability to complete assessments at the time of enrollment, and/or interfere with follow ups.
3. Subjects who, in the investigator's opinion, are unable to understand the protocol or to give informed consent, have a history of poor cooperation, noncompliance with medical treatment, or difficulty in returning for follow up care. A legally authorized representative may provide consent if the potential subject lacks the capacity to provide consent themselves.

Patients who received STaRT (GammaTile) intraoperatively.