FDG PET/CT在精确放疗中应用的初步研究

目的：研究FDG PET/CT在肿瘤病例中的成像特点和对精确放疗的影响.方法：2009年8月至2011年5月,72例肿瘤患者在放疗前接受GE Discovery PET/CT定位扫描.图像资料传至Varian Eclipse 8.6治疗计划系统.将FDG在各组织器官及肿瘤病灶中的聚积水平分为四个等级（＋-＋＋＋＋）,分析PET成像特点并探讨PET/CT图像融合对放疗的影响.结果：通常情况下,肿瘤病灶和正常脑组织、膀胱肾盏肾盂FDG聚积水平最高（＋＋＋＋）;肝脏、脾脏、椎体次之（＋＋＋）;大部分肌肉和胃肠道、胰腺FDG稍低（＋＋）;肺和皮肤最低（＋）.非肿瘤性FDG高聚积多见于左心室、咽喉周围、局部肠道内以及创伤或炎症病变等部位.PET/CT图像融合使肿瘤病灶更易被发现,因此约22％病例病灶数增加.此外,约62.5％放疗靶区受PET/CT融合图像影响发生了较明显改变.结论：FDG PET/CT在放疗的应用有利于复杂解剖部位肿瘤的边界确定及早期肿瘤病灶的发现和治疗,而非肿瘤性FDG高聚积是最主要的不良影响因素.

Preliminary study on FDG PET/CT application in the precision radiotherapy

Objective：To research imaging characteristic and the influence of Fusion Fluoro - deoxy - glucose Pos- itron Emission Tomography/ Computed Tomography （ FDG PET/CT） to precision radiotherapy in tumor patients. Methods：From 2009 to 2011,72 patients were conducted FDG PET/CT scanning（ type of Discovery, GE. Co. ） be- fore radiotherapy. Images data were transferred to the Treatment Planning System （TPS, Eclipse 8.6, Varian Co. ）. The FDG accumulation in all tissues and organs and tumor lesion were divided into four levels（ ＋ - ＋ ＋ ＋ ＋ ）. The PET imaging characteristics was analyzed, and the PET/CT image fusion influence on radiotherapy was discussed. Results： In general, the accumulation level of FDG in tumor, brain, bladder, renal calices and renal pelvis is always the highest （ ＋ ＋ ＋ ＋ ） ,and in liver,spleen and centrums it is higher（ ＋ ＋ ＋ ） ,and in most part of muscle tissue and gastroin- testinal tract,pancreas ,it is lower（ ＋ ＋ ） ,and in lungs and skin it is always lowest（ ＋ ）. The non -tumor high FDG accumulation zone was often found in the left ventricle, around laryngopharynx, local intestine tract, trauma sites, or in- flammation sites, and so on. PET/CT image fusion make the tumor lesions to be detected more easily, so lesion number was increased in about 22% cases. In addition, about 62.5 % target area was obviously changed by PET/CT image fu- sion involved in radiotherapy. Conelusion：FDG PET/CT in the radiotherapy is helpful to determine the boundary of the tumor in complex anatomical site, to discover and treat early tumor lesion, and non - tumor FDG accumulation is the main negative factor.