An in vivo technique for the measurement of bone blood flow in animals

A new technique to measure the in vivo clearance of 41Ar from the bone mineral matrix is demonstrated following fast neutron production of 41Ar in bone via the 44Ca(n, alpha) reaction at 14.1 MeV. At the end of irradiation, the 41Ar activity is assayed with a Ge(Li) detector where sequential gamma-ray spectra are taken. Following full-energy peak integration, background and dead time correction, the activity of 41Ar as a function of time is determined. Results indicated that the Ar washout from bone in rats using this technique was approximately 16 ml (100 ml min)-1 and in agreement with other measurement techniques. For sheep the bone perfusion in the tibia was approximately 1.9 +/- 0.2 ml (100 ml min)-1.