TISSUE-PREPARATION TECHNIQUE FOR MICROSPHERE ASSAYS OF BLOOD-FLOW

A simple method for preparing standardized tissue samples for microsph ere assay of tissue blood dow is described, By reduction of tissue sam ples into a liquid state and centrifugation of the microspheres to the bottom of conical-shaped counting vials, the microspheres within all tissue and blood reference samples attain the same counting geometry. The validity and reproducibility of this technique has been establishe d for planar-configured gamma-ray detectors in an in-situ porcine kidn ey model. A positive correlation coefficient of r = 0.99 was observed between the total kidney blood flow, as measured by a calibrated Trans onic flow probe, and the microsphere reference sample technique.