In-LOOP synthesis of ~(11)C-Triphenylmethylphosphonium for myocardial perfusion imaging

Background:99mTc-MIBI was used as myocardial perfusion SPECT.However,the high accumulation of tracers in the liver and lung may hinder the detection of flow abnormalities in myocardium.Purpose: 11C-Triphenylmethylphosphonium(11C-TPMP) was a lipophilic cation,has been investigated as a positron emission tomography(PET) agent for myocardial and tumor imaging to provide a better temporal and spatial resolution than SPECT.Methods: 11C-TPMP was prepared by reacting [11C]methyl trifalte with In-LOOP method.Biodistribution studies in mouse were performed.And micro PET was performed with rat,and compared with 4-[18F]fluorophenyl triphenylphosphonium ion(18F-FTPP).Results: The results showed that the 11C-TPMP labeling yield was over 90%,the radiochemical purity was over 98%.The biodistribution showed high accumulation of radioactivity in the heart(71.9±19.9)%ID.g–1 at 5 min and(12.87±0.81)%ID.g–1at 60 min post injection.The heart/liver ratios were 11.57 and 3.2 at 5 min,60 min respectively.Micro PET scans showed distinct accumulation of 11C-TPMP in the myocardium from 20 min to 60 min.The liver had very lower accumulation of radioactivity.Conclusions: 11C-TPMP was a promise PET perfusion agent for myocardial.It would be useful in clinical with In-LOOP synthesis.