FDG hPET-CT显像对非小细胞肺癌合并肺不张适形放疗靶区确定的影响

Using 18F-deoxyglucose γ-camera PET to Target Tumors in Atelectatic Lung in Non-small Cell Lung Cancer Patients Treated with Three-dimensional Conformal Radiotherapy

目的:通过与常规CT检查对比分析探讨了氟脱氧葡萄糖γ-相机型PET-CT(hPET-CT)显像对非小细胞肺癌(NSCLC)合并肺不张患者行三维适形放疗(3D-CRT)时病变靶区确定的临床意义。方法:对17例经组织学和(或)细胞学检查确诊为非小细胞肺癌且CT检查合并肺不张者,先后行胸部CT平扫和(或)强化CT和hPET-CT检查,分别勾画出大体肿瘤体积CT-GTV和hPET-CT-GTV,并分别制定出三维适形放疗的GTV进行比较。结果:全部患者的CT-GTV与hPET-CT-GTV均有不同程度的差别,其中2例患者的hPET-CT-GTV较CT-GTV增加20%(28.5cm3),CT-GTV平均为142.5㎝3,hPET-CT-GTV平均为171cm3;15例患者Hpet-CT-GTV较CT-GTV平均减少19.3%(26㎝3),CT-GTV平均为135㎝3(95-190㎝3),hPET-CT-GTV平均为109㎝3(65～155㎝3)(P=0.004)。GTV的减少主要原因是hPET-CT显像除外了与肿瘤组织在CT上不能区分的肺不张组织,从而导致靶区的缩小,使靶区更加精确,且避免周围正常组织不必要的照射,最大限度地保护了正常组织,显示了3D-CRT的优点。结论:hPET-CT显像对非小细胞肺癌(NSCLC)伴肺不张患者的肺不张组织与肺癌组织的鉴别有意义,提高了靶区定位的精确性。

Objective： To investigate the potential benefit of using 18F-deoxyglucose γ-camera PET-CT （FDGhPET-CT） to delineate the gross tumor volume （GTV） of non-small cell lung cancer （NSCLC） complicated with atelectasis in patients who are to be treated with three-dimensional conformal radiotherapy （3DCRT） in comparison to patients undergoing conventional inspection. Methods： Seventeen patients with histopathologieally and cytologically confirmed NSCLC complicated with varying degrees of atelectasis were studied. All patients were scanned with both thoracic CT and 18F-deoxyglucose γ-camera PET-CT. The GTV was delineated based on both CT image and hPET-CT image （CT-GTV, hPET-CT-GTV） and the GTV from each imaging technique （designated CT-GTV and hPET-CT-GTV） was compared before and after treatment. Results： The paired CT-GTV and hPET- CT-GTV values for each patient were different from each other. Fifteen of 17 patients＇ GTV was reduced an average of 19.3% （26 ㎝^3） with a median CT-GTV of 135 ㎝^3 （95-190 ㎝^3） and a median hPET-CT-GTV of 109 ㎝^3 （65-155 ㎝^3） （P=0.004）; 2 of 17 patients＇ GTV increased by 20% （28.5 cm^3）. The lower values obtained for hPET-CT-GTV were due to the ability of hPET-CT to differentiate cancer-induced atelectasis from gross tumor, reducing the target volume and sparing more of the surrounding normal tissue. This factor alone displays the superiority of 3DCRT using hPET-CT. Conclusions： The incorporation of hPET-CT data with gross tumor delineation improves the aecuracy of 3D- CRT for non-small cell lung eancer patients with atelectasis complications.