Blood flow in proximal femur of the dog determined by the local 133Xe injection method.

A new approach for measuring blood flow in bone is presented. It consists of the local injection of 133Xe into the proximal femur of adult beagles and the external measurement of isotope washout curves. The curves were analyzed using a two-compartment exponential model. The half-times for the tracer washout from the fast and slow compartment were 3.34 +/- 0.48 min and 33.6 +/- 11.7 min (mean +/- 1 S.D.) respectively. Blood flow was calculated using a measured blood to bone partition coefficient of 1.55 ml/g. The mean blood perfusion in proximal femur of the dog was 10.8 +/- 4.3 ml/100 g/min (mean +/- 1 S.D.). This value agrees well with most estimates of bone circulation. Due to rapid disappearance of 133Xe the method is easy to repeat and is thus suitable for physiological studies of local blood flow in bones.