In-Human CXCR4 Imaging of Hematologic and Solid Tumors Using [68Ga]-Pentixafor-PET

Inclusion Criteria: Twenty patients with histologically proven treatment-naïve, therapy-refractory or relapsed blood cancers meeting the below criteria will be included: * Indolent B- or T-cell Non-Hodgkin lymphoma (including cutaneous lymphomas) or Non-Hodgkin lymphoma with variable FDG uptake and clinical course, such as mantle cell lymphoma; and measurable disease according to Lugano criteria or * Histiocytic neoplasms (Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD) and/or Rosai-Dorfman disease (RDD) * MGUS/SMM or MM according to IMWG definitions * Solid tumors, such as lung cancers, meningioma, adrenocortical neoplasms including cortisol-producing adenomas or high suspicion for tumor, such as in patients with Cushing's disease. * Age ≥18 * Negative serum pregnancy test for female volunteers of childbearing age and potential (as defined by MSKCC Standards \& Guidelines) from assays obtained \<2 weeks prior to study enrollment/intervention; or negative urine pregnancy test performed on the day of intervention * MSKCC patients Exclusion Criteria: * Breast-feeding * History of renal functional disorders (chronic kidney disease with eGFR\<30) * Refusal or inability to tolerate the scanning procedure (e.g., due to claustrophobia)