What will light up on a bone scan due to renal excretion?

What will light up on a bone scan due to renal excretion?

• A. Sternum
• B. Epiphysis in a child
• C. Calcaneus
• D. Bladders

Answer: (D)

In a Tc-99m bone scan, the tracer is cleared from the blood by the kidneys and excreted into the urine. That means the urinary tract, especially the bladder where urine collects, will light up due to the excreted radiotracer. The other sites—sternum, a child’s growth plates, or the calcaneus—light up because of bone turnover and metabolism, not because of renal excretion. So the bladder showing activity reflects the normal excretion pathway of the tracer.