COMPARTMENTAL ANALYSIS OF THE STEADY-STATE DISTRIBUTION OF O-15(2) AND (H2O)-O-15 IN TOTAL-BODY

  • 1 January 1981
    • journal article
    • research article
    • Vol. 22  (11) , 959-965
Abstract
Regional O2 metabolism may be measured quantitatively by analysis of the steady-state distribution of 15O (t1/2 = 122 s). For this analysis a compartmental model that incorporates corrections due to clearance and recirculation of H2O of metabolism was developed. The O2 utilization rate is simply proportional to the local 15O activity if H2O of metabolism is not recirculated from other tissues and is not lost to the circulation for a time long compared with the t1/2 of 15O. The magnitude of biological metabolic H2O loss and uptake in the steady state was evaluated. Analysis indicates that the magnitude of these effects for rapidly exchanging tissues (such as cerebral gray and white matter) may preclude a simple, noninvasive and quantitative determination of regional O2 metabolism. Slowly exchanging compartments (such as skeletal muscle and perhaps some tumors) appear amenable to correction for clearance and recirculation effects with sufficient accuracy to make determinations of regional O2 metabolism feasible.