^(18)F-FDG hPET(hybrid PET)与CT对NSCLC区域淋巴结放疗的影响的比较——剂量学分析  

The impact of ^(18)F-FDG-hPET(hybrid PET) and CT lymph node imaging on the radiotherapy of non-small-cell lung cancer—dosimetry analysis

作　　者：张碧媛[1] 傅小龙[1] 蒋国梁[1] 章英剑[2] 陈兰飞[1] 胡伟刚[1] 周莉钧[1] 

机构地区：[1]复旦大学附属肿瘤医院放疗科,复旦大学上海医学院肿瘤学系,上海200032 [2]复旦大学附属肿瘤医院核医学科,复旦大学上海医学院肿瘤学系

出　　处：《中国癌症杂志》2006年第4期281-286,共6页China Oncology

摘　　要：背景与目的PET作为一种功能性影像技术,它对判定纵隔淋巴结癌转移的准确性显著优于CT。由于dPET(dedicated PET—专用型PET)价格昂贵,尚难在中国普及,国内不少医院是应用廉价得多的hPET(hybridPET—兼容型PET)进行FDG显像。虽然双探头的hPET的信噪比和空间分辨率低于环形探测器的dPET,但文献报道hPET和dPET对NSCLC区域淋巴结的定性诊断的吻合性可达93%。本研究探讨由18F-FDG hPET所提供的淋巴结转移的定性诊断信息参与设计非小细胞肺癌(NSCLC)的放疗计划与单用CT设计放疗计划相比,是否能产生剂量学影响和带来治疗增益的改变。方法49例经病理证实的NSCLC患者接受了同期(2周内)增强CT和hPET检查,选择了其中hPET和CT所显示区域淋巴结(N)转移情况不同且无远处转移的患者15例。对此15例患者,分别根据CT和hPET勾画GTV(大体靶体积)和PTV(计划靶体积),再对不同PTV进行三维适形放疗计划设计和优化,比较两者的PTV及DVH(剂量体积直方图)的差异,根据Lyman模型推算保持与基于CT的放疗计划相同的肺放射性损伤(NTCP)情况下,基于hPET设计的放疗计划的肿瘤靶区剂量及肿瘤控制率(TCP)的改变。结果15例患者中,由于hPET比CT检出了更多的转移淋巴结而使PTVhPET>PTVCT7例,平均扩大(25.2±3.9)cm3(P=0.000);由于hPET排除了部分CT阳性的淋巴结而使PTVhPET<PTVCT8例,平均缩小(47.4±3.6)cm3(P=0.000)。在给予相同的靶区剂量6000cGy/30次时,hPET参与后PTV缩小者的肺V20、MLD(平均全肺剂量)、食管V55、V45、MHD(平均全心剂量)及NTCP均显著降低,而PTV扩大者的相应指标均显著增加。在达到相同的肺NT-CP情况下,hPET参与后PTV缩小者靶区剂量可增加(675.0±99.6)cGy(P=0.00),TCP可能上升(3.4±0.5)%(P=0.01),hPET参与后PTV扩大者靶区剂量可能降低(600.0±138.0)cGy(P=0.005),TCP可能下降(3.1±0.8)%(P=0.026)。结论当hPET参与NSCLC的放疗计划设计时,由于hPET对纵隔淋�Background and purpose： As a functional image technology, PET has showed much more accuray than CT in the detection of metastases of mediastinal lymph node of non-small-cell lung cancer. The dedicated PET （dPET） has not been widely available in China due to its high cost, instead, the dual-head coincident gamma camera imaging that was also called hybrid PET （hPET） was commonly used to acquire FDG image. Despite the fact that hPET with dual-head detector has a lower target-background ratio and spatial resolution than that of the dPET with a ring detector, it was reported that the hPET scans had a high concordance of 93% with dPET in detection of local regional lymph node metastases of NSCLC. The purpose of this study was to estimate the impact of integrating hPET lymph node imaging into the treatment planning for the patients with non-small-cell lung cancer treated by radiation and to assess the differences between the planning with/without hPET by planning target volume（PTV）, dose-volume histogram（DVH）, tumor control probability（TCP） and normal tissue complication probability （NTCP）. Methods： 49 patients with pathologically proven non-small-cell lung cancer had undergone both enhanced CT and hPET examination within 2 weeks. 15 cases without remote metastases showed different local lymph node metastases in CT scan or hPET scan. For these 15 patients, two three-dimensional conformal treatment plans were made and optimized： one with a CT-based planning target volume （PTV） and one with a hPET-based PTV, both to be delivered by 6 000 cGy in 30 fractions. Both PTV and DVH were compared, assumed to keep same lung radiation injury probability as the treatment plan based on CT, the maximal tolerable prescribed radiation dose for the plan with hPET-based PTV was evaluated, thus the tumor control probability （TCP） was estimated. Results： Among the 15 patients, the PTV based on hPET （PTVhPET） was larger than that based on CT alone （PTVCT） in 7 patients, the mean difference was

关 键 词：单光子发射型计算机体层摄影术 ^18氟脱氧葡萄糖 非小细胞肺癌 淋巴结转移 放疗计划 治疗比 

分 类 号：R730.44[医药卫生—肿瘤]