Describe the phases of a three-phase bone scan.

Describe the phases of a three-phase bone scan.

Blood flow phase: Images are obtained immediately after injection of the tracer and document arterial flow.


Blood pool phase: Images are obtained immediately after the blood flow phase. This phase shows the tracer at equilibrium in the extracellular space.


Delayed (late) phase: Images are obtained 2 to 4 hours after injecting the tracer, as with a standard bone scan.