Browsing by Author "Tofighi, Mojdeh"
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Item In vitro and in vivo study of Tc-99m-MIBI encapsulated in PEG-liposomes: A promising radiotracer for tumour imaging(Springer, 2003-04) Belhaj-Tayeb, Hayet; Briane, Dominique; Vergote, Jackie; Kothan, Suchart; Leger, Gerard; Bendada, Saad-Eddine; Tofighi, Mojdeh; Tamgaç, Feyzi; Uludağ Üniversitesi/Tıp Fakültesi/Nükleer Tıp Anabilim Dalı.; 0000-0002-2325-7728; 35569192500Encapsulation of technetium-99m sestamibi (Tc-99m-MIBI) in polyethyleneglycol-liposomes (Tc-99m-MIBI-PEG-liposomes) could extend the duration of its circulation in blood and alter its biodistribution, enabling its concentration in tumours to be increased. An original method to encapsulate Tc-99m-MIBI in PEG-liposomes is described. The Tc-99m-MIBI-PEG-liposomes were compared with free Tc-99m-MIBI with respect to (a) tumour availability (b) ability to distinguish between chemotherapy-sensitive and -resistant cells and (c) uptake ratio in tumour imaging. PEG-liposomal systems composed of distearoylphosphatidylcholine/cholesterol/PEG(2000)-distearoyl phosphatidylethanolamine and lissamine-rhodamine B-labelled liposomes were used. The encapsulation of 99mTc-MIBI in liposomes was achieved using the K+ diffusion potential method. We compared the uptake of free versus encapsulated Tc-99m-MIBI by sensitive and resistant erythroleukaemia (K562) and breast tumour (MCF-7ras) cells. To assess the internalisation of these liposomes into cells, rhodamine B-labelled PEG-liposomes were used and visualised by fluorescence microscopy. Biodistribution and imaging characteristics of encapsulated and free radiotracer were determined in rats and tumour-bearing nude mice. The efficiency of Tc-99m-MIBI encapsulation in PEG-liposomes was 50+/-5%. Use of Tc-99m-MIBI-PEG-liposomes did not impair the ability of this tracer to distinguish between chemotherapy-sensitive and -resistant tumour cells; the percentage of radio-activity accumulated in the sensitive K562 cells was 1.24+/-0.04%, as compared with 0.41+/-0.04% in the resistant K562 cells. One hour post injection in rats, PEG-liposomes showed a ten times higher activity in blood than free Tc-99m-MIBI, whereas activity of free Tc-99m-MIBI in kidneys and bladder was markedly higher than that of encapsulated Tc-99m-MIBI, indicating faster clearance of the free radiotracer. In the (MCF7-ras)-bearing nude mice, PEG-liposome uptake in tumour was two times that of free Tc-99m-MIBI. Summarising, the Tc-99m-MIBI-PEG-liposomes demonstrated a longer blood circulation time, enabled distinction between chemotherapy-sensitive and -resistant cells and improved tumour to background contrast in in vivo imaging. Tc-99m-MIBI-PEG-liposomes therefore show promising potential for tumour imaging.Item The interest of (18)FDG-PET in the management of testicular cancer(Masson Editeur, 2004-02-28) Tofighi, Mojdeh; Baillet, Georges; Weinmann, Pierre; Moretti, Jean Luc; Tamgaç, Feyzi; Uludağ Üniversitesi/Tıp Fakültesi.; 0000-0002-2325-7728; 35569192500The key to prognosis initial staging and early recurrence diagnosis are key parameters in the treatment and outcome of testicular cancer. Initial staging. It is difficult using conventional modalities, which can miss node involvement and are non-specific since enlargement does not rime with involvement. (18)FDG PET improves the accuracy of initial staging. Residual mass and recurrences Existence of residual mass or enhancement of its volume in the presence of an otherwise beneficial chemotherapy is difficult to manage. Several studies have demonstrated the value of (18)FDG imaging in such cases. As for follow-up whole body (18)FDG can prevent multiple diagnostic imaging and can diagnose recurrences with greater diagnostic accuracy than with other imaging modalities.