Verification of 99mTc-ethylenedicysteine (99mTc-EC) distribution model in the organism.
BACKGROUND
The aim of the present study was an attempt to verify the systemic distribution of 99mTC-ethylenedicysteine by means of the open two-compartment model.


METHODS
In order to accomplish this, 99mTc-EC clearance was determined in 21 patients as: two-compartmental model-based plasma clearance, and a urinary clearance, i.e. utilising the 99mTc-EC activity excreted with urine during a finite time interval.


RESULTS
There is a close correlation (r = 0.97) between the clearance values determined according to these two methods, and the rectilinear orthogonal correlation equation assumes a C1ECu = 1.03656C1ECp - 18.064 form. The slope of the line does not differ significantly from unity. The shift of the correlation line along the X-axis indicates a minor excretion of the radiopharmaceutical also by routes different from the urinary tract, e.g. with the bile.


CONCLUSIONS
The performed comparison of the clearance values has proved that distribution of 99mTc-EC in the organism is consistent with the open two-compartment model.
Department of Nuclear Medicine, Medical University of Łódź, Poland. zmnmjsur@psk2.am.lodz.pl
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