- The subject has a clinically acceptable medical history, physical examination and vital signs findings during the screening period (from within 21 days before administration of 18F-VM4-037). Components of an acceptable medical history include no active infection at the time of enrollment or within 7 days of enrollment, no prior therapy that results in immunocompromise or impaired renal function (serum creatinine within 2 weeks prior to positron emission tomography (PET) imaging less than or equal to1.8 mg/dl and epidermal growth factor receptor (eGFR) must be > 30 ml/min/1.73m^2) or findings indicating an inability to tolerate the requirements for the scan. Previous exposure to immunocompromising therapy does not exclude the patient; patients must have an absolute neutrophil count > 1.5/microL within 2 weeks of PET imaging.