演題

Development of MR-NOTES system using real-time MRI navigation and nano-micelle contrast media

[演者] 仲 成幸:1
[著者] 村上 耕一郎:1, 山田 篤史:2, 貝田 佐知子:1, 赤堀 浩也:1, Horacio Cabral:3, 片岡 一則:3, 森川 茂廣:4, 谷 徹:2, 谷 眞至:1
1:滋賀医科大学 消化器外科, 2:滋賀医科大学 バイオメディカルイノベーションセンター, 3:東京大学 工学部, 4:滋賀医科大学 看護学科

Introduction: The clinical application of Natural Orifice Translumenal Endoscopic Surgery (NOTES) is associated with some difficulties such as spatial disorientation and a lost target. We have developed MRI (Magnetic Resonance Image) navigation system for the endoscopic surgery to overcome such difficulties. Nano-micelles have been demonstrated as an effective method of targeting drugs to malignant tumors with enhancement permeability and retention (EPR) effect. Nano-micelles can selectively accumulate in tumors at high concentrations, thus increasing the detection and targeting.
Materials and Methods: MR-compatible fiber scope is consist of non-ferromagnetic parts and the diameter of insertion segment is 11mm. The MR gradient-based tracking system (EndoScout) provides the real-time 6-degree of freedom position information. Augmented reality (AR) technique was utilized to fuse the Endoscopic camera view and 3D tumor target. MR-NOTES procedures were carried out on anesthetized pigs (approx. 30kg) in 1.5T MRI scanner. Gd-DTPA/DACHPt-loaded nano-micelles are 33 nm in diameter and containing the T1-weighed MRI contrast agent Gd-DTPA and the parent complex of the anticancer drug oxaliplatin, that is DACHPt, for simultaneous imaging and therapy. These nano-micelles were injected into the hepatic artery in an orthotopic rat HCC model and MRI performance was assessed.
Results and Discussion: Clear real-time MR images and clear endoscopic images were obtained. The virtual 3D image of tumor with AR technique was accurately indicated the target location in the endoscopic image. Tumor intensity of T1-weighted MR images increased considerably after injection of nano-micelles and remained stable for up to 3 hr in an orthotopic rat HCC model. MR -NOTES System which we have developed may enable us to overcome spatial disorientation and a lost target associated.
Conclusion: This MR-NOTES system can realize safer and more accurate surgical procedure of NOTES.
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