title: Novel99mTc(III) Complexes [99mTcCl(CDO)(CDOH)2B-R] (CDOH2= Cyclohexanedione Dioxime) Useful as Radiotracers for Heart Imaging.
abstract: In this study, we evaluated seven new99mTc(III) complexes [99mTcCl(CDO)(CDOH)2B-R] (99mTc-2Fboroxime: R = 2-formylfuran-3-yl (2F);99mTc-3Fboroxime: R = furan-3-yl (3F);99mTc-5Fboroxime: R = 5-formyfuran-2-yl (5F);99mTc-HPboroxime: R = 6-hydroxylpyridin-2-yl (HP);99mTc-MPYboroxime: R = 5-methoxypyridin-3-yl (MPY);99mTc-PMboroxime: R = 1,5-pyrimidin-3-yl (PM); and99mTc-4PYboroxime: R = pyridin-4-yl (4PY)) for their potential as heart imaging agents. All new99mTc(III) radiotracers except99mTc-2Fboroxime were prepared with high radiochemical purity (RCP > 95%). The low RCP (∼75%) for99mTc-2Fboroxime is most likely caused by steric hindrance from the 3-formyl group. Biodistribution and imaging studies were performed in SD rats. Planar image quantification was performed to compare their myocardial retention times. We found that the myocardial washout curves of new99mTc(III) radiotracers were best fitted the biexponential decay function. The AUC (area under the curve) values followed the general trend:99mTc-5Fboroxime (129 ± 6) >99mTc-3Fboroxime (114 ± 11) >99mTc-Teboroxime (104 ± 16) >99mTc-MPYboroxime (92 ± 18) >99mTc-4PYboroxime (77 ± 10) >99mTc-PMboroxime (68 ± 14) ≈99mTc-HPboroxime (62 ± 14). The 2 min heart uptake values from biodistribution studies follow the ranking order of99mTc-5Fboroxime (3.75 ± 0.15%ID/g) ≈99mTc-MPYboroxime (3.73 ± 0.24%ID/g) >99mTc-PMboroxime (3.47 ± 0.15%ID/g) ≈99mTc-3Fboroxime ≈ (3.25 ± 0.77%ID/g). The 5 min heart uptake of99mTc-5Fboroxime (3.91 ± 0.09%ID/g) was almost identical to its 2 min heart uptake (3.75 ± 0.15%ID/g), and its 15 min heart uptake value (2.83 ± 0.08%ID/g) compared well to the 2 min heart uptake of99mTc-Teboroxime (3.00 ± 0.37%ID/g). It took ∼5 min for99mTc-5Fboroxime to approach the 1 min heart uptake value of99mTc-Teboroxime (∼3.5% ID/g) and ∼9.5 min to reach the 2 min heart uptake value of99mTc-Teboroxime (∼3.0% ID/g). The best image acquisition window is 0-5 min for99mTc-5Fboroxime. High-quality single-photon emission computed tomography images of the rat hearts were acquired in any of the 5 min window over the first 20 min after its administration.99mTc-5Fboroxime has significant advantages over99mTc-Teboroxime as the radiotracer for myocardial perfusion imaging.
authors.affiliation: Department of Radiation Medicine and Protection, Medical College, Soochow University , China.|School of Health Sciences, Purdue University , Indiana 47907, United States.
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Nuclear Medicine, Fuwai Hospital, the National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Fang
authors.affiliation: School of Health Sciences, Purdue University , Indiana 47907, United States.
authors.forename: Shuang
authors.initials: S
authors.lastname: Liu
mesh_terms: D000818:Animals; D006321:Heart / Q000000981:diagnostic imaging*; D007700:Kinetics; D055414:Myocardial Perfusion Imaging; D015609:Organotechnetium Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics; D010091:Oximes / Q000737:chemistry; D011849:Radioactive Tracers; D011854:Radiochemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D015609:Organotechnetium Compounds; D010091:Oximes; D011849:Radioactive Tracers