I don't think it can trace tumores inside your bone, Ct would probably do so.A PET scan demonstrates the biological function of the body before anatomical changes take place, while the CT scan provides information about the body's anatomy such as size, shape and location. Currently, PET scans are most commonly used to detect cancer, heart problems (such as coronary artery disease and damage to the heart following a heart attack), brain disorders (including brain tumors, memory disorders, seizures) and other central nervous system disorders.