Phase I Trial to Determine the Dose and Evaluate the PK and Safety of Lutetium Lu 177 Edotreotide Therapy in Pediatric Participants With SSTR-positive Tumors

This study tests a radioactive drug called Lutetium-177 edotreotide — which delivers targeted radiation directly to tumor cells — in children with rare cancers called SSTR-positive tumors (tumors that have a specific protein receptor on their surface), including certain brain tumors and neuroendocrine tumors. **You may be eligible if...** - You are between 2 and 17 years old - You have a confirmed diagnosis of an SSTR-positive tumor (cancer with specific surface receptors) - Your cancer has come back or stopped responding to at least one previous treatment - You are otherwise well enough to participate **You may NOT be eligible if...** - You have significant kidney, liver, or bone marrow problems - You have had recent radiation therapy to the same areas - You are pregnant (or could be pregnant) - Your cancer does not test positive for SSTR receptors Talk to your doctor to see if this trial is right for you.