胰腺癌平扫或强化氟脱氧葡萄糖PET—CT图像靶区勾画研究

Gross tumor volume delineation with combination of non-contrast/contrast CT and FDG PET in pancreatic cancer

目的探讨平扫或强化氟脱氧葡萄糖（FDG）PET—CT图像在胰腺癌靶区勾画中的作用。方法回顾分析本院2008--2009年问21例局部晚期不可切除及术后复发胰腺癌患者资料，以相同固定体位分别行平扫CT、PET，其中11例之后行强化CT。将扫描数据输入治疗计划系统，行平扫或强化CT、PET图像融合，分别依据强化CT、平扫CT、平扫PET及平扫或强化PET—CT融合图像勾画大体肿瘤体积（CTV），并用配对或成组t检验比较不同图像GTV大小。结果21例患者平扫GTVCT、平扫GTVPFT、平扫或强化GTVPncT平均值分别为76．9、47．0、44．5cm^2，平扫GTVPE-CT平均体积明显小于平扫GTVCT（z=-3．91，P=0．000）。11例强化GTVCT、强化GTVPET、强化GTVPET-CT平均体积分别为64．1、45．1、49．3cm^2，强化GTVPET-CT平均体积明显小于强化GTVCT（==-2．13，P=0．033），强化GTVPET-CT平均体积与平扫GTVPET-CT相似（z=-0．80，P=0．424）。结论PET和强化或平扫CT的融合图像能提高不可切除胰腺癌靶区勾画准确性，有望降低放疗不良反应。

Objective To investigate the application of non-contrast and contrast-enhanced is FDG PET/CT in the delineation of gross tumor volume （GTV） of pancreatic cancer. Methods Between Jan. 2008 and Dec. 2009, twenty-one patients with unresectable locally advanced pancreatic cancer or recurrent pancreatic cancer after surgery in our hospital had both non-contrast CT and PET images acquired at the same body position. Among the whole group, eleven patients also had contrast CT images. The image data sets were transferred to the treatment planning workstation for registration. Then gross tumor volumes （GTV） were delineated independently using the information of PET images, contrast/non-contrast CT scan and contrast/non-contrast PET-CT fusion images. The differences of mean volume in these different sets of GTV were analyzed. Results For the whole group, the mean volume of non-contrast GTVCT, GTVpET, noncontrast GTVPET-CT were 76. 9 cm3 , 47. 0 cm3 and 44. 5 cm3 , respectively. The mean volume of non-contrast GTVPET-CT was significantly smaller than non-contrast GTVCT （ z = - 3. 91, P = 0. 000）. For the eleven patients with contrast CT, the mean volume of contrast GTVcT, GTVpET , contrast GTVpET.CT were 64. 1 cm3 , 45. 1 cm3 and 49. 3 cm3 ,respectively. The mean volume of contrast GTVpET_Cr was significantly smaller than contrast GTVCT （z = - 2. 13, P = 0. 033 ）. No significant differences were found between contrast PET-CT and non-contrast PET-CT （z = -0. 80,P = 0. 424）. Conclusions Co-registration of PET and contrast/non- contrast CT information in pancreatic cancer may improve the accuracy of GTV delineation, and possibly reduce the adverse effect of irradiation.