A multiphase bone scintigraphy (bone scan) is a nuclear medical examination including blood flow images, immediate images, and delayed images.
The blood flow study is a dynamic sequence of planar images of the bone region of interest obtained during the injection of the radiopharmaceutical (radioactive tracer).
The immediate phase (blood pool or soft tissue study) include one or more static images of selected regions, obtained immediately after the blood flow phase within 10 min.
Delayed images (usually whole body) are usually acquired 2-5 hours after injection. Later (6-24 hour) delayed images result in a higher target to background ratio and may permit better evaluation of the pelvis if this was obscured by bladder activity on the routine images. This late imaging may be particularly helpful in patients with renal insufficiency or peripheral circulatory disorders and those with urinary retention.