GD2-SADA:177Lu-DOTA Complex in Patients With Solid Tumors Known to Express GD2

This study tests a new type of targeted radiation treatment that uses a molecule designed to find and attach to a protein called GD2, which is found on certain solid tumors. It delivers a radioactive payload directly to cancer cells. **You may be eligible if...** - You are 18 or older (or 16+ for high-risk neuroblastoma or sarcoma) - Your cancer is known to express the GD2 protein - Your tumor can be measured on a scan - You are in reasonably good health (ECOG 0–1) with expected survival over 3 months - Your blood counts and kidney function meet minimum requirements **You may NOT be eligible if...** - Your tumor cannot be measured - You have poor organ function or severe health issues - You are under 16 years old Talk to your doctor to see if this trial is right for you.