This is a technetium-99 MDP radioisotope bone scan. The radioactive molecule
attaches to bone crystals only when bone is actively being formed or destroyed.
Such a scan is positive (with "hot spots" seen as black areas) in 70% of cases
of ischemic osteonecrosis. Here the tooth-bearing portion of the jaws (alveolar bone)
is completely black, top and bottom. The base of the skull
(sphenoid sinus area) is also involved.