This phase I trial studies how well zirconium (Zr)-89 crefmirlimab berdoxam and immuno-positron emission tomography (PET) identifies areas of immune cell activity in patients with brain tumors that can be removed by surgery (resectable). One important predictor of the immune response is the presence and change in CD8 positive (+) tumor infiltrating lymphocytes (TIL) cells. Identifying the presence and changes in CD8+ cells can be challenging, particularly for participants with central nervous system (CNS) tumors, and usually requires invasive procedures such as repeat tissue biopsies, which may not accurately represent the immune status of the entire tumor. Zr-89 crefmirlimab berdoxam is known as a radioimmunoconjugate which consists of a radiolabeled anti-CD8+ minibody whose uptake can be imaged with PET. Upon administration, Zr 89 crefmirlimab berdoxam specifically targets and binds to the CD8+ cells. This enables PET imaging and may detect CD8+ T-cell distribution and activity and may help determine the patient's response to cancer immunotherapeutic agents more accurately. Giving Zr-89 crefmirlimab berdoxam along with undergoing immuno-PET imaging may work better at identifying immune cell activity in patients with resectable brain tumors.

"This phase I trial investigates the effect of radiation therapy on the immune system, specifically CD8 positive (+) T cells, in lymphoma patients receiving bridging radiation therapy before CAR T-cell infusion, and metastatic patients with solid tumor malignancies receiving SBRT. CD8+ T cells are mainly found in lymph tissue and play a significant role in anti-tumor immunity. These cells can infiltrate tumor cells and kill them. Radiation therapy may recruit CD8 T cells and this recruitment may help with tumor control. Diagnostic procedures, such as zirconium Zr 89-Df-crefmirlimab positron emission tomography (PET), may be a less invasive way to check and monitor for CD8+ T cells before and after radiation therapy."