Development of fluorescence guided navigation system using a near infra-red fluorescent agent

我们开发了一种近红外荧光可视化系统，并将其应用于脑肿瘤动物模型的肿瘤检测。在本实验中，我们使用吲哚青绿(ICG)作为荧光增强材料。用780 nm激光激发光照射手术野。近红外荧光用红外摄像机结合800 nm低通滤光片显示。我们证实ICG积聚在颅内肿瘤中，其荧光清晰地显示为透过薄颅、大脑皮质和硬脑膜物质的明亮区域。为改进普通5-氨基酮戊酸(5-ALA)肿瘤可视化系统，研制了激光荧光手术内窥镜系统，并将其应用于脑室内肿瘤的活检。脑室内肿瘤通常被室管膜上皮覆盖，确切的存在变得模糊。这种激光荧光手术内窥镜系统使我们能够找到准确的肿瘤范围，确保可靠的肿瘤活检。另一个改进点是将5-ALA荧光引导下的肿瘤切除应用于恶性胶质瘤以外的另一种脑肿瘤。至于脑膜瘤是最常见的中枢神经系统良性肿瘤，我们发现80%以上的脑膜瘤表现出来自5-ALA的强烈荧光。在恶性脑膜瘤的情况下，并蔓延到周围结构，如脑、血管和颅骨，有肿瘤残留和局部复发的风险。5-ALA荧光引导手术是预防肿瘤残留和复发的良好临床应用。

We developed a near infra-red fluoscopic visualizing system and applied it to detect the tumor of the animal model of brain tumor. In this experiment, we employed the indocyanin green (ICG) for the fluorescent enhanced material. The excitation light from 780 nm laser was irradiated the operative field. The near infra-red fluorescence were visualized using infra-red CCD camera combined with low pass filter of 800 nm. We confirmed that ICG was accumulate to the intracranial tumor and its fluorescence was clearly visualized as a bright area through the thin skull, cerebral cortex, and dura matter. In conclusion, near infra-red fluorescence tumor visualizing system has advantageous to detect the deep seated cryptic tumor.In order to improve the ordinary tumor visualizing system using 5-aminolevulinic acid (5-ALA), we developed the Laser fluorescent operative endoscopic system, and applied it for biopsy of the intra-ventricular tumor. Intra-ventricular tumors are often covered by the ependymal epithelium and the exact existence become vague. This laser fluorescent operative endoscopic system enables us to find us the exact tumor extend and ensure the reliable tumor biopsy.Another improved point was to apply the fluorescence guided tumor removal using 5-ALA to another brain tumor other than malignant glioma. As for the maningiomas, which are the most popular benign neoplasm at the central nervous system, we fond that the more than 80 % of maningiomas showed the strong fluorescence derived from 5-ALA. In the cases of malignant menintiomas and extended to surrounding structures, such as brain, vessels, and skull, has a risk of tumor residue and local recurrence. The 5-ALA fluorescent guided surgery is a good clinical application in such cases to prevent from tumor residue and recurrence.