Individually optimum therapy based on less invasive bio-imaging in brain yumors

脑肿瘤的治疗结果仍然令人沮丧和不满意，尽管最近的发展在治疗模式。正电子发射断层扫描（PET）是一种微创的生物成像技术，在发现中枢神经系统（CNS）病变的早期异常方面比解剖学成像更敏感，研究者已将PET与各种示踪剂广泛应用于脑肿瘤和非肿瘤性CNS疾病，大多数非肿瘤性CNS疾病的氧代谢仍然较低，而CNS感染如结节病和脑脓肿的氧代谢则增加。11 C-甲基-L-甲硫氨酸PET图像显示肿瘤细胞作为热病变存在，其特征在于即使在肿瘤的狭窄病变中也有明显的积聚。<18>氟脱氧葡萄糖（FDG）不是脑肿瘤的特异性示踪剂，而是作为糖代谢指标的生理性示踪剂。FDG可掺入正常组织如脑和肌肉中。位于灰质的恶性脑肿瘤并不总是说明“热”图像不同于周围组织。改进的方法（使用代谢转移）在大脑中的FDG抑制有一些优势，使肿瘤“热”的可视化与周围的脑组织更不同。<18>氟多巴（DOPA）PET反映多巴胺能细胞的局部定位，并揭示基底神经节的轮廓。DOPA摄取模式的分散意味着肿瘤向基底节的弥漫性浸润生长，从而限制了手术切除，而扭曲意味着肿瘤对基底节及其周围组织的扩张性生长，多学科生物成像研究可以使我们建立肿瘤特异性，并对个体脑肿瘤的血流动力学和代谢特征，因此，量身定制的治疗方式更可行。

The therapeutic results of brain tumors remain dismal and unsatisfactory in spite of recent development in therapeutic modalities. Less invasive bio-imaging using positron emission tomography (PET) is expected to be more sensitive than anatomic imaging in detecting early abnormalities of the central nervous system (CNS) lesions .The investigators have extensively applied PET with various tracers on brain tumors and non-tumor CNS diseases.Oxygen metabolism remained low in most non-tumor CNS diseases, whereas it increased in CNS infections such as sarcoidosis or brain abscess. The 11C-methyl-L-methionine PET images illustrate the existence of tumor cells as a hot lesion, characterized by marked accumulation, even in a narrow lesion of tumor.^<18>F-Fluorodeoxyglucose (FDG) is not a specific tracer to brain tumors but a physiologic tracer as an indicator of glucose metabolism. FDG incorporates in normal tissue such as brain and muscles. Malignant brain tumors located in the gray matter do not always illustrate "hot" image differently from the surrounding tissue. Modified methods (using metabolic shift) of FDG depression in the brain have some advantage that visualizes the tumors "hot" more differently from the surrounding brain tissue.^<18>F-Fluorodopa (DOPA) PET reflects a topographic localization of dopaminergic cells and reveals the contour of basal ganglia. Dispersion of DOPA uptake pattern implies diffusely infiltrating growth of tumor into the basal ganglia, thus limiting surgical resection, whereas distortion implies expansive growth of the tumor against the basal ganglia of and surrounding tissue.Multidisciplinary bio-imaging studies may allow us to establish tumor-specificity, and to hemodynamically and metabolically characterize individual brain tumors; accordingly, tailor-made treatment modalities are more feasible.