胰腺癌平扫或强化氟脱氧葡萄糖PET-CT图像靶区勾画研究

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年间 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(GTV),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 GTV_CT、平扫 GTV_PET、平扫或强化 GTV_PET-CT平均值分别为76.9、47.0、44.5 cm³,平扫 GTV_PET-CT平均体积明显小于平扫GTV_CT (z=－3.91,P=0.000)。11例强化 GTV_CT、强化 GTV_PET、强化 GTV_PET-CT平均体积分别为64.1、45.1、49.3 cm³,强化 GTV_PET-CT平均体积明显小于强化GTV_CT (z=－2.13,P=0.033),强化 GTV_PET-CT平均体积与平扫 GTV_PET-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。

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

Objective To investigate the application of non-contrast and contrast-enhanced ¹⁸FDG 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 GTV_CT, GTV_PET, non-contrast GTV_PET-CT were 76.9 cm³, 47.0 cm³ and 44.5 cm³, respectively. The mean volume of non-contrast GTV_PET-CT was significantly smaller than non-contrast GTV_CT(z=－3.91, P=0.000). For the eleven patients with contrast CT, the mean volume of contrast GTV_CT, GTV_PET, contrast GTV_PET-CT were 64.1 cm³, 45.1 cm³ and 49.3 cm³,respectively. The mean volume of contrast GTV_PET-CT was significantly smaller than contrast GTV_CT(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.