Normal FDG PET Biodistribution

B. Brain, myocardium, liver, and urinary tract

Normal FDG distribution includes: (1) BRAIN — highest uptake due to obligatory glucose dependence; (2) MYOCARDIUM — variable uptake depending on fasting state (high in fed state, suppressed in fasted); (3) LIVER — moderate uniform uptake; (4) URINARY TRACT (kidneys, ureters, bladder) — FDG is excreted unchanged in urine; (5) SPLEEN — mild uptake. Skeletal muscle uptake is low at rest but increases significantly with exercise. Recognizing normal FDG distribution is critical to avoid misinterpreting physiologic uptake as pathology.