A system for measuring muscle mass of a patient has a dual-energy radiation emission source. A radiation detector is configured to detect radiation emitted from the dual-energy radiation emission source passed through the patient. A processor has a memory with storing instructions, that when executed by the processor, perform a set of operations. The operations include receiving radiation detection data; generating a scan representation; identifying a primary fat target; determining an amount of fat in the primary fat target; comparing the amount of fat in the primary fat target to a reference; and based on the comparison, correcting an estimated amount of lean tissue to generate a corrected muscle mass value.