Technetium-94m-teboroxime: synthesis, dosimetry and initial PET imaging studies.
Technetium-94m (T1/2 = 53 min) allows the in vivo study of technetium radiopharmaceuticals with positron emission tomography (PET). PET provides a quantitative assay of radioactivity with excellent temporal and spatial resolution, revealing biodistributions that were previously available only through in vitro assay methods. Technetium-94m, produced by the proton irradiation of natural molybdenum on an 11 MeV cyclotron, was extracted with an electrochemical etching technique. Technetium-94m-pertechnetate was prepared to make the myocardial perfusion agent teboroxime in an identical manner as 99mTcO4-. The increased absorbed radiation dose requires a sevenfold reduction in administered activity compared to 99mTc-teboroxime. Eleven clinical PET studies were performed and visually compared to 13N-ammonia. The clearance half-time for 94mTc-teboroxime was approximately 8 min, with a peak myocardial extraction of approximately 3% of the injected dose into a 400-g heart. These results confirm the potential of 94mTc PET for quantitatively studying the pharmacokinetics of new, and old, technetium agents in man.
Nickles
R J
RJ
Department of Medical Physics, University of Wisconsin, Madison.
Nunn
A D
AD
Stone
C K
CK
Christian
B T
BT
D000328:Adult; D000368:Aged; D000641:Ammonia; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009590:Nitrogen Radioisotopes; D015609:Organotechnetium Compounds / Q000138:chemical synthesis; D010091:Oximes; D011829:Radiation Dosage; D011874:Radiometry; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
D009590:Nitrogen Radioisotopes; D015609:Organotechnetium Compounds; D010091:Oximes; C081873:technetium Tc 94m teboroxime; D000641:Ammonia