Regional blood-flow measurement in rabbit soft-tissue tumor with positron imaging using the C15O2 steady-state and labeled microspheres.

The C15O2 steady-state method, with tomographic measurement of H215O, has been used to measure blood flow in normal muscle tissue and a soft-tissue tumor (V2) in rabbits. the method has been validated in a rabbit tumor model by comparison of the data with that observed using microspheres labeled with Sc-46 and Ga-68. The blood-flow values found with the C15O2 steady-state method, after correction for tissue blood volume, agree well with values gained with labeled microspheres. The effect of blood volume on apparent blood flow in tumor was about 50%. The tissue/blood partition coefficients were 0.94 +/- 0.05 for healthy tissue and 1.16 +/- 0.15 for tumor tissue. After correction for partition coefficient and blood-volume effects, the blood-flow value for normal tissue was 4.1 +/- 1.3 ml/min-100 cc, and for the tumor tissue 10.7 +/- 2.3 ml/min-100 cc.