Pg. Melon et al., MYOCARDIAL KINETICS OF K-38 IN HUMANS AND COMPARISON WITH COPPER-62-PTSM, The Journal of nuclear medicine, 35(7), 1994, pp. 1116-1122
The aim of this study was to define the kinetics of K-38 and its suita
bility to evaluate myocardial blood flow at rest and during pharmacolo
gical vasodilation in normal subjects. Potassium-38's kinetic characte
ristics were also compared to those of a Cu-62-pyruvaldehyde bis((n)4-
methyl-thio-semicarbazone) copper (II) (PTSM) flow tracer. Methods: Po
tassium-38 and (CU)-C-62-PTSM were injected at rest and after pharmaco
logical vasodilation in six healthy volunteers. Dynamic PET acquisitio
n was performed over 20 min and myocardial tracer retention calculated
. Homogeneity of regional myocardial tracer distribution was also eval
uated. Results: High image quality of the heart was observed at rest a
nd after dipyridamole with both tracers. Potassium-38 demonstrated pro
longed myocardial retention with minimal lung and liver accumulation.
In contrast to K-38, Cu-62-PTSM demonstrated high liver uptake which m
ay hinder observation of the inferior wall of the myocardium. Copper-6
2-PTSM dipyridamole-to-rest retention ratio was 1.49. Conclusions: Pot
assium-38 and Cu-62-PTSM display suitable kinetics for the qualitative
evaluation of blood flow and flow reserve in the human heart. Compare
d to Cu-62-PTSM, potassium-38, which does not show high liver uptake,
may more accurately estimate blood flow in the inferior wall of the he
art. However, accurate quantification of myocardial blood flow using K
-38 or Cu-62-PTSM retention appears to be limited to decreasing retent
ion fraction at hyperhemic states.