title: Imaging of metastatic pulmonary tumors following NIS gene transfer using single photon emission computed tomography.
abstract: The Na+/I- symporter (NIS) is a membrane glycoprotein that facilitates the uptake of iodine into thyroid follicular cells. Recently, we and others have demonstrated the feasibility of imaging subcutaneous xenografts expressing exogenous NIS, suggesting that NIS may serve as an imaging reporter gene to monitor vector delivery and therapeutic gene expression. In this study, we established NIS-expressing pulmonary tumors in nude mice to investigate the minimal tumor size required for in vivo detection of pulmonary tumors by single photon emission computed tomography (SPECT) with pinhole collimation. In order to define the anatomic location of NIS-expressing tumor nodules detectable by SPECT, we performed simultaneous, dual-isotope imaging. We injected 1 mCi 99mTc-MAA via tail vein to image pulmonary perfusion and injected 1 mCi Na125I intraperitoneally to image NIS-expressing tumors. Fused images showed that 99mTc-MAA perfusion defects correlated with NIS-mediated 125I uptake. Post-mortem analysis revealed that tumors 3 mm in diameter could be detected by SPECT with pinhole collimation. These studies demonstrate the feasibility of SPECT to detect pulmonary tumors expressing exogenous NIS in mice.
authors.affiliation: Medical Scientist Program, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Derek K
authors.initials: DK
authors.lastname: Marsee
authors.forename: Daniel H Y
authors.initials: DH
authors.lastname: Shen
authors.forename: Lawrence R
authors.initials: LR
authors.lastname: MacDonald
authors.forename: Douangsone D
authors.initials: DD
authors.lastname: Vadysirisack
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Lin
authors.forename: George
authors.initials: G
authors.lastname: Hinkle
authors.forename: Richard T
authors.initials: RT
authors.lastname: Kloos
authors.forename: Sissy M
authors.initials: SM
authors.lastname: Jhiang
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D005822:Genetic Vectors; D007457:Iodine Radioisotopes; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D051381:Rats; D027981:Symporters / Q000235:genetics*; D013668:Technetium Tc 99m Aggregated Albumin; D015899:Tomography, Emission-Computed, Single-Photon; D000099209:Sodium-Iodide Symporters
chemical_list: D007457:Iodine Radioisotopes; D027981:Symporters; D013668:Technetium Tc 99m Aggregated Albumin; D000099209:Sodium-Iodide Symporters