A 52-year-old man presented to the emergency department with a 3-day history of fevers and left flank pain radiating to the chest and neck. Total WBC count was 20,000/uL. Abdominal CT demonstrated small bibasilar pleural effusions. Because of persistent leukocytosis, an 111In WBC scintigram was ordered 5 days after admission, which demonstrated thoracic WBC accumulation on the planar images that localized to the left posterior chest wall on SPECT/CT. SPECT/CT may differentiate intrathoracic versus extrathoracic disease.