In a first proof-of-concept human application in a group of five patients with hematological cancers, [99mTc]Tc-PentixaTec was well tolerated, allowed high-contrast delineation of CXCR4 expressing tumors, and exhibited a favorable overall biodistribution and dosimetry profile. Here, CXCR4 is linked to hematopoietic and lymphoid cell neoplasm.