99mTcN-NOET (bis[N-ethoxy,N-ethyl]dithiocarbamato nitrido technetium (V)) has been proposed for myocardial perfusion imaging. Biodistribution, safety, and dosimetry were studied in 10 healthy volunteers (5 at rest and 5 during exercise).
Methods: Biodistribution was studied by acquiring dynamic images up to 60 min after injection and whole-body images up to 24 h after injection. The MIRDOSE3 analysis program was used for radiation dosimetry calculations.
Results: Safety parameters measured to 48 h after injection revealed no clinically significant changes. Cardiac uptake of 99mTcN-NOET was high (2.9%-3%), with biologic half-life of 210-257 min on average. Lung uptake of 99mTcN-NOET was higher (10%-20%) but, on average, biologic half-life was shorter (1-77 min). Clearance from the blood was rapid (5% by 5 min). Radiation dosimetry calculations indicated an effective absorbed dose of 5.11 x 10(-3) mSv/MBq at rest and 5.38 x 10(-3) mSv/MBq after exercise.
Conclusion: 99mTcN-NOET exhibits high cardiac uptake and an estimated effective absorbed dose comparable with that of the other 99mTc-labeled compounds used in myocardial perfusion imaging.