摘要目的 探讨PET-CT在食管癌临床分期诊断和三维适形放疗靶区勾画及治疗计划制定中的应用价值.方法 2007-2008年经病理证实的食管癌患者20例人组,其中2例接受手术治疗,18例行三维适形放疗.患者疗前行PET-CT模拟定位,比较食管镜、食管钡餐造影、CT、PET-CT_(SUV2.5)、PET-CT_(40%SUVmax)图像上的病变长度及最大横径,观察CT与PET-CT对临床分期诊断的差异.依据CT、PET-CT_(SUV2.5)和PET-CT<40%SUVmax>勾画靶区并制定治疗计划,评价3套计划受量情况.结果 食管镜、食管钡餐造影、CT、PET-CTS_(SUV2.5、PET-CT_(40%SUVmax))所示病变长度分别为4.93、5.06、6.67、5.89、4.84 cm,CT、PET-CT_(SUV2.5)、PET-CT_(40%SUV)所示病变最大横径分别为4.05、3.38、2.95 cm.CT图像诊断31个淋巴结转移,PET-CT图像诊断21个淋巴结转移,共同诊断14个,17个淋巴结CT诊断阳性而PET-CT为阴性,7个淋巴结CT诊断阴性而PET-CT为高代谢.5例患者经PET-CT模拟定位后M分期由Mn期改为_1期,1例经PET-CT模拟定位后由M_0期改为M_1期,1例CT和PET-CT M分期一致.依据CT和PET-CT_(SUV2.5)勾画的GTV基本相等2例,CTV_(CT)<GTV_(SUV2.5)者5例,>GT_(SUV2.5)者13例,GTV_(SUV2.5),<GTV_(CT)组患者正常组织受量较低.结论 以SUV2.5为阈值勾画的GTV长度可能与实际病变长度最为接近,其次是食管钡餐造影;以40%SUV_(max)为阈值勾画GTV有可能会较低估计实际病变长度.PET-CT使部分患者临床分期及治疗目的 发生改变,部分患者靶区范围或体积减少,正常组织受量降低.

abstractsObjective To investigate the value of PET-CT in TNM staging and three-conformal radiotherapy (3DCRT) in esophageal carcinoma. Methods From September 2007 to November 2008, 20 patients with pathologically confirmed esophageal carcinoma were enrolled, including 2 treated with surgery and 18 with 3DCRT. All the patients received PET-CT simulation before the treatment. The length and maximum transverse diameter of Grit based on esophagoscope, esophagography, CT, PET-CT_(SUV2.5) and PET-CT_(40%SUVmax) were compared. The TNM stages were compared based on CT and PET-CT images. Three treatment plans were produced and analyzed based on images of CT, PET-CT_(SUV2.5) and PET-CT_(40%SUVmax),respectively. Results The length of lesion on esophagoscope, esophagography, CT, PET-CT_(SUV2.5) and PET-CT_(40%SUVmax) was 4. 93 cm, 5.06 cm, 6. 67 cm, 5. 89 cm and 4. 84 cm, respectively. The corresponding maximum transverse diameter on the last 3 images was 4. 05 cm, 3.38 cm and 2. 95 cm, respectively. In all, 31, 21 and 14 positive lymph nodes were identified according to CT images, PET-CT images and the both. Five patients with CT diagnosed stage M_0 were found to have distant metastasis by PET-CT images, and 1 patient with CT diagnosed stage M_1 was excluded by PET-CT. The volumes of GTV_(CT) were similar with GTV_(SUV2.5) in 2 patients, smaller in 5 patients, and larger for the remaining 13 patients. For these 13 patients, the radiation dose of normal tissues based on GTV_(SUV2.5) was relatively lower. Conclusions The length of lesion based on PET -CT_(SUV2.5) matches the pathological length best , followed by esophagography. With PET-CT_(40%SUVmax) the actual lesion length may be underestimated. TNM stage might be changed by PET-CT, and then the target volumes and radiation doses of normal tissues might be reduced.