Sternal Marrow Circulation by the Radioisotope Clearance Technique.

blood flow and marrow activity still remain unanswered. The demonstrated feasibility of measuring the regional circulation of a given tissue from the disappearance rate of a locally deposited, diffusible, radioactive tracer substance (1) stimulated some interest in the application of this technique to the study of the blood flow of the marrow (2-4). This rather simple tech nique has been variously modified by these investigators to yield divergent data which have been interpreted generally as useful measurements of the capillary blood flow of the marrow. In the light of these reported diverse findings the present study was under taken to re-evaluate the applicability of the tracer clearance technique to the study of bone marrow blood flow.