Dose Escalation Study of CLR 131 in Pediatric Relapsed/Refractory Malignant Tumors Including Neuroblastoma and Sarcomas

Inclusion Criteria: All Patients * Previously confirmed (histologically or cytologically) pediatric solid tumor (e.g., neuroblastoma, sarcoma), lymphoma (including Hodgkin's lymphoma), or malignant brain tumors that are clinically or radiographically suspected to be relapsed, refractory, or recurrent for which there are no standard treatment options with curative potential. Note: patients with diffuse intrinsic pontine glioma (DIPG) may enroll without histological or cytological confirmation. * ≥ 2 years of age and ≤ 25 years of age at time of consent/assent * If ≥ age 16 years, Karnofsky performance status of ≥ 60. If \< age 16 years, Lansky performance status ≥ 60 * Platelets ≥ 75,000/µL (last transfusion, if any, must be at least 1 week prior to study registration, and, unless deemed medically necessary, no transfusions are allowed between registration and dosing) * Absolute neutrophil count ≥ 750/µL * Hemoglobin ≥ 8 g/dL (last transfusion must be at least 1 week prior to study registration, and, unless deemed medically necessary, no transfusions are allowed between registration and dosing) * Using the bedside Schwartz formula, estimated GFR (creatinine clearance) \> 60 ml/min/1.73m2 * Alanine aminotransferase \< 3 × ULN * Bilirubin \< 2 × ULN * Patients who have undergone autologous or allogeneic bone marrow transplant must be at least 3 months from transplant. * Patients enrolling at total dose levels \> 30 millicurie (mCi)/m2 must have availability or ability to colle…