If the radiotracer moves evenly through the bones, there is no anomaly and the result is considered normal.
If certain areas show increased or decreased accumulation of radiotracer material as compared to the surrounding areas, then the scan findings are abnormal in respect to those areas.
Areas that absorb little amount of tracer, will appear dark and are called as cold spots. This is also indicative of lack of blood supply to the bone and this is seen in cases of cancer.
Areas that absorb more amount of tracer are seen bright and are called as hot spots. They are seen in cases of fracture/ infection/trauma.