Bone Marrow Scanning:
The agent used for marrow scanning is Technetium-sulfur colloid and it can be used to assess hematopoiesis. A defect on marrow scanning can be used to identify marrow replacement by tumor and occasionally to assess the femoral head vascular supply. Increased tracer activity is seen with marrow expansion (hematopoietically active bone marrow such as in sickle cell anemia). The expansion of the marrow in patients with Sickle Cell makes Tc-SC marrow scanning useful for the detection of femoral head AVN.
Unexpected ectopic bone marrow may occur in the appendicular skeleton after trauma and repeated surgical interventions [1].
Tc-SC marrow imaging is often used in conjunction with In-111 WBC imaging particularly in the evaluation of suspected orthopedic hardware infection and in Charcot joint infection (due to ectopic marrow).
REFERENCES:
(1) J Nucl Med 1998; Kaim A, et al. Ectopic hematopoietic bone marrow in the
appendicular skeleton after trauma. 39: 1980-1983
