ABSTRACTS PRESENTADOS AL 11th INTERNATIONAL SYMPOSIUM "RADIONUCLIDES IN NEPHRO-UROLOGY", REALIZADO EN MONTEREY, CALIFORNIA, 13-17 MAYO 2001.
5. EXPRESSING RENAL FUNCTION IN TRACER KINETIC TERMS.
M
D Rutland, I M Hassan and L Que.
Auckland Hospital Nuclear Medicine Department, New Zealand
Glomerular
function is usually expressed as a volume clearance rate ie ml/min.,
and this needs to be normalized to compensate for differences in patient
sizes. Tracer kinetics represent organ function as the rate of tracer
movement into or out of an organ. As no volume is involved, it is
possible that no normalizing is needed.
Gamma camera DTPA renograms were used to calculate the fraction of
tracer in the blood which is taken up by the kidneys per million seconds,
and this is called the Fractional Uptake Rate (FUR). Data from patients
with presumed normal renal function are presented below, divided into
age bands and also split into the larger and smaller half of all the
patients within each age band. The index of body size used was the
surface area (SA).
Using the t-test, every age band showed a highly significant difference in the SAs, with p-values less than 0.001. However, no age bands showed a significant difference in the FUR values, with all p-values > 0.05. Thus, when renal function is expressed in terms of tracer kinetics, normalizing to a uniform patient size does not seem to be needed. In addition, children appear to have better renal function than adults, which may explain why they have lower serum creatinine levels.
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