Measurement of blood flow into pools by radioactive tracers

Based upon the analysis of pulse-height spectra a data processing method has been developed for the determination of the ''effective depth'' of point, spherical and cylindrical sources containing 137Cs and sup(113m)In positioned within a semi-infinite absorbing medium. The method has been used for measurements of the blood flow rate into a pool and studies have been performed on patients undergoing investigations of the blood flow in the placenta using sup(113m)In. The computer programme was found reliable for predicting the depth of radionuclide point sources below the water surface as well as for predicting the pulse-height spectra when the depth is known. The ''effective depth'' of finite radionuclide sources with different volumes was to be accurately represented by the position of the center of the mass of the source only if additional corrections are applied