Single Photon Emission Computed Tomography Tracer

Multifunctional Iron Oxide Nanocarriers Synthesis for Drug Delivery, Diagnostic Imaging, and Biodistribution Study

The aim of the current study is to design the radiolabeled and drug-loaded nanocarrier with high loading capacity and pH-dependent drug release characteristics that could effectively transport loaded compounds to various organs for efficient diagnostic imaging and chemotherapeutic drug delivery. The aqueous extract of green tea leaves was used to synthesize the small-sized iron oxide nanoparticles (IONPs). The nanoparticles were characterized with UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray analysis (EDX). Iron oxide nanoparticles with sizes smaller than 50 nm were successfully synthesized, making them suitable for in vivo studies. In drug loading trials, 94% of the drug was loaded onto the active surface of iron oxide nanoparticles from the solution. The in vitro drug release study revealed that an acidic environment (pH 4.5) effectively triggers the release of doxorubicin (DOX) from the nanoparticles as compared to a neutral environment (pH 7.4). The gamma-emitting radionuclide ^99mTc was successfully labeled with IONPs for biodistribution and imaging studies. The efficiency of radiolabeling was observed to be ≥ 99%. Furthermore, the in vivo biodistribution study of radiolabeled IONPs in rabbit model showed rapid accumulation in various organs such as heart, liver, and kidneys. This work suggested that green synthesized iron oxide nanoparticles are potential nanocarriers for diagnostic imaging and efficiently distributing DOX to specific organs. The aqueous extract of green tea leaves was used for the facile green synthesis of iron oxide nanoparticles (IONPs). Furthermore, the chemotherapeutic drug doxorubicin (DOX) and gamma-emitting radionuclide ^99mTc were loaded on these iron oxide nanoparticles to evaluate the in vivo biodistribution and drug delivery studies in the rabbit models.

Effective Labeling of Amine Pharmacophores through the Employment of 2,3-Pyrazinedicarboxylic Anhydride and the Generation of fac-[M(CO)3(PyA)P] and cis-trans-[M(CO)2(PyA)P2] Complexes (PyA = Pyrazine-2-carboxylate, P = Phosphine, M = Re, 99mTc)

The fac-[M(CO)₃(PyA)(P)] and cis-trans-[M(CO)₂(PyA)(P)₂] neutral complexes (M is Re or ^99mTc), based on the mixed ligand strategy with pyrazine-2-carboxylic acid (PyAH) as the bidentate N,O and triphenylphosphine as the monodentate P ligand, are presented. Through the employment of the anhydride of pyrazine-2,3-dicarboxylic acid (PyDA), the PyAH scaffold was conveniently derivatized with the model bioactive amine 1-(2-methoxyphenyl)piperazine, the active part of the 5-HT_1A antagonist WAY100635. Reaction of either PyAH or the pharmacophore-bearing PyAH ligand (L¹H) with fac-[M(CO)₃]⁺ core in water yielded the intermediate fac-[M(CO)₃(PyA)(H₂O)] complexes. The labile aqua ligand was easily replaced by PPh₃ to yield the fac-[Re(CO)₃(PyA)(PPh₃)] complexes, while in toluene under reflux, the cis-trans-[Re(CO)₂(PyA)(PPh₃)₂] complexes were obtained. The latter complexes were alternatively obtained from mer-[Re(CO)₃(PPh₃)₂Cl] by refluxing with the PyA ligand in toluene. The analogous ^99mTc complexes were synthesized quantitatively, showing excellent stability in competition studies. The methodology described herein represents a practical procedure for the effective integration of the fac-[M(CO)₃]⁺ core with amine-bearing biologically active compounds for diagnosis/therapy.

Diagnosis of Cardiac Rehabilitation after Percutaneous Coronary Intervention in Acute Myocardial Infarction Patients by Emission Computed Tomography Image Features under Filtered Back Projection Reconstruction Algorithm

This study aimed to explore the application value of emission computed tomography (ECT) imaging technology based on filtered back projection reconstruction algorithm (FBP) in cardiac function examination after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Eighty patients with myocardial infarction diagnosed by medical history, electrocardiograph (ECG), and myocardial enzyme admitted to hospital from February 2018 to February 2019 were selected as the research objects. All patients underwent PCI seven days after the onset of myocardial infarction. ECT was performed for all patients before and after surgery. In addition, all ECT images were processed by the FBP reconstruction algorithm. On this basis, preoperative and postoperative cardiac surgery function and ischemia of the patients were diagnosed. Then, the diagnostic results were compared with the results of coronary angiography and echocardiogram. The results showed that all patients had a total of 541 segments before PCI surgery. ECT examination revealed 294 abnormal segments of the ventricular wall, with a total score of 585 points. A total of 100 segments were scored with 1 point, a total of 194 segments were scored with 2 points, and a total of 50 segments were scored with 3 points. After PCI, the number of abnormal segments was reduced to 58, with a total score of 193. There were 6 segments with a score of 1, 44 segments with a score of 2, and 5 segments with a score of 3. The left ventricular diastolic volume (EDV), left ventricular systolic volume (ESV), stroke volume (CO), and ejection fraction (EF) of the patients before the operation were 148 ± 16 mL, 77 ± 14.5 mL, 4.29 ± 0.37 L/min, and 41.9 ± 8%, respectively. The EDV, ESV, CO, and EF of the patients after surgery were 132 ± 16 mL, 62 ± 13 mL, 4.89 ± 0.71, and 53 ± 6%, respectively. Significant changes occurred in various systolic function parameters before and after surgery, P < 0.05. The standardized regression coefficients of the three groups were 0.32, 0.41, and 0.47, respectively, P < 0.05, which indicated that the greater the coronary artery stenosis rate, the higher the diagnostic coincidence rate of left anterior descending limb (LAD), left circumflex branch (LCX), and left coronary artery (RCA). The conformity of ECT imaging in the LCX group for diagnosis of myocardial ischemia was higher than that of UCG, P < 0.05. To sum up, the ECT technology based on the FBP reconstruction algorithm had a good application prospect in the diagnosis of cardiac function recovery in AMI patients after PCI.