title: Biodistribution characteristics and SPECT imaging of (99m)Tc-RET and (99m)Tc-REG in human lung cancer xenografts.
abstract: OBJECTIVE
  To investigate the biodistribution and single-photon emission computed tomography (SPECT) imaging of (99m)Tc-labeled arginine-glutamic acid-threonine (RET) and arginine-glutamic acid-glycine (REG) in nude mice bearing human lung cancer xenografts.
  
  
  METHODS
  RET and REG were labeled directly with (99m)Tc and their binding efficiency to tumor cells was measured in human nonsmall cell lung cancer H1299 cells. After intravenously injecting (99m)Tc-RET and (99m)Tc-REG into normal mice and nude mice bearing human lung cancer xenografts, their biodistribution was measured at different postinjection times, and percentages of injected dose per gram tissue (% ID/g) of organs of interest were calculated. The mice bearing H1299 lung cancer xenografts were scanned by SPECT at different times following the (99m)Tc-RET or (99m)Tc-REG injection.
  
  
  RESULTS
  The radiochemical purity of (99m)Tc-RET and (99m)Tc-REG was 93.15%±2.02% and 92.90%±2.86%, respectively. The binding rate of (99m)Tc-RET and (99m)Tc-REG to H1299 cells was 3.56%±0.37% and 2.32%±0.31%, respectively. The uptake of (99m)Tc-RET and (99m)Tc-REG in tumor was 4.96±1.05% ID/g at 4 hours postinjection and 1.95±0.73% ID/g at 2 hours postinjection, respectively. Tumors in nude mice could be best imaged at 4.5-6 hours postinjection of (99m)Tc-RET.
  
  
  CONCLUSIONS
  (99m)Tc-RET has a higher binding rate to H1299 cells than (99m)Tc-REG and might be used as a potential lung cancer imaging agent.
authors.affiliation: 1 Department of Nuclear Medicine, The First Affiliated Hospital of Soochow University. Suzhou , Jiangsu, P.R. China .
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Xie
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: Wang
authors.forename: Ci-Yi
authors.initials: CY
authors.lastname: Liu
authors.forename: Cheng
authors.initials: C
authors.lastname: Chang
authors.forename: Bei
authors.initials: B
authors.lastname: Lei
authors.forename: Yi-Wei
authors.initials: YW
authors.lastname: Wu
mesh_terms: D000818:Animals; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009842:Oligopeptides / Q000493:pharmacokinetics*; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: D009842:Oligopeptides; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals
keywords: lung neoplasma; peptides; pharmacokinetics; technetium