PET/CT在放射治疗中的应用价值

正电子发射断层扫描仪／计算机体层扫描（positron emission tomography／computed tomography，PET／CT）同机融合是1种先进的影像诊断系统，它可更精确地确定原发肿瘤、区域转移淋巴结以及远处转移病灶的位置和范围，对肿瘤放疗前治疗计划的制定、放疗疗效的评价、放疗后复发或残留的鉴别以及放疗后预后的评估等方面均具有重要作用。     

PET-CT图像融合在食管癌精确放疗中的应用

目的探讨PET-CT融合图像勾画靶区的食管癌三维适形放疗计划的优势。方法对16例食管癌病例分别进行CT、PET同机扫描,图像重建后传输至三维治疗计划系统(3D-Treatment planning system,TPS),进行自动图像融合,由同一临床医师分别在CT、PET-CT融合图像上勾画出,同一物理师分别设计优化TPS计划,给予常规处方剂量2.0Gy×30次,每个计划采用5个方向照射野来实现较好的靶区剂量分布,并达到周围正常组织保护的目的。计算各计划的靶区体积并显示剂量体积直方图(dose-volume histogram,DVH),比较2个计划的全肺平均受量(mean lung dose,MLD)、双肺受照超过20Gy的体积占全肺体积的百分比(V20)、气管平均受量、心脏平均受量、脊髓最大受量。结果CT勾画的GTV体积均值为67.10cm3,大于PET-CT融合图像下勾划的GTV均值60.82cm3,包括MLD、全肺V20、气管平均受量、心脏平均受量、脊髓最大受量在内的各项DVH参数的比较显示,均以PET-CT勾画靶区的计划明显优于CT勾画靶区的计划。结论PET-CT图像融合基础上勾画靶区制定放疗计划,可更有效的保护周围正常组织和器官。     

3D-CRT结合同步化疗治疗Ⅲ期非小细胞肺癌的随机分组研究

[目的]研究三维适形放射治疗（3D-CRT）大剂量分割同步给予铂类为主的化学药物治疗不能切除的Ⅲ期非小细胞肺癌（NSCLC）的可行性。[方法]自2000年8月至2003年6月，将90例符合入选条件的Ⅲ期非小细胞肺癌患者随机分为3组，1组30例，以铂类为主的化疗＋3D-CRT常规分割组；2组30例，为单纯3D-CRT常规分割组；3组30例，以铂类为主的化疗＋3D-CRT大剂量分割组。1、2组分割剂量1．8—2Gy／次，5次/周，总剂量66～66．6Gy／6～8周，3组4．5～5Gy／次，3次/周，总剂量45Gy／4～5周.[结果]1、2、3组的3年总生存率和无病生存率分别为33.3％、20．0％、36．6％和23.3％、16．6％、23．3％，中位生存期分别为31、20、32个月。1、3组明显好于2组（1组和2组比较．Х^2=3．87．P=0．0492；2组和3组比较，Х^2=4．28．P=0．0387）．2组的中位转移时间为22个月，与1组的31．5个月、3组的30．5个月比较，有显著性统计学意义（1组和2组比较Х^2=4．71，P=0．0301；2、3组比较Х^2=4．02，P=0．0449）。1、2、3组的中位复发时间分别为27．5、32、28个月，无显著性统计学差异（1、2组比较Х^2=0．42，P=0．5177；1、3组比较Х^2=0．001，P=0．9636；2、3组比较Х^2=0．44，P=0．5066）。急性放射性食管炎：1、2、3组的发生半分别为46．7％、43．3％、63．3％。1、2、3组发生放射性肺炎的例数接近（Х^2=1．440，P=0．487），以Ⅰ级反应为主。[结论]3D-CRT联合化疗降低了Ⅲ期非小细胞肺癌患者的远处转移率，提高了总生存率和无病生存率。大剂量分割结合同步化疗可缩短疗程．提高局部控制率．但发生早期和晚期放射性损伤的概率增加．     

18F-FDG PET/CT显像监测胃癌术后复发转移的价值

Objective PET with 18F-fluorodeoxyglucose (FDG) has been used to beth detect and stage a variety of malignancies. The aim of this retrospective study was to evaluate the clinical value of 18F-FDG PET/CT for recurrence and metastasis in gastric carcinoma patients after total gastrectomy. Methods A total of 45 gastric carcinoma patients who underwent total gastrectomy were included. PET/CT scans were obtained for restaging. The " gold standard" of 18F-FDG PET/CT diagnostic accuracy was based on either histopathology or clinical follow-up. By using the t-test from SPSS 11.5, the cut-off of maximum standard-ized uptake values (SUVmax) from 18F-FDG to differentiate benign from malignant lesion at stomach were determined and calculated. Results (1) Of the 45 patients, 22 were suspicion recurrent lesion at stomach. Of the 22 patients, 12 were confirmed to have recurrent lesions. The diagnostic accuracy were 100.0% (12/ 12) for sensitivity, 70.0% (7/10) for specificity, and 86.4% (19/22) for accuracy, respectively. A higher SUVmax in malignant than benign lesion was noted (6.27 ± 3.42 vs 3.92 ± 2.24), though not reached to the significance (t = 1. 862, P > 0.05). (2) For extra-gastric lesion detection, the sensitivity, specificity, and accuracy for region lymph nodes were 78.9% (15/19), 92.3% (24/26), and 86.7% (39/ 45), for peritoneal spreading were 6/9, 97.2% (35/36), 91. 1% (41/45), and for distant sites were 86.7%(13/15), 93.3% (28/30), 91.1% (41/45). (3) False positive were found in eight sites. All were either inflammatory or physiological uptake at intestine. False negative were found in nine sites. Either due to small in size (less than 1.0 cm in diameter), well differentiation of the tumor cell or with a nature of signet ring. Conclusion 18F-FDG PET/CT had a potential to detect local, regional, and distant metastasis in gastric cancer.     

18F-FDG PET/CT显像监测胃癌术后复发转移的价值

Objective PET with 18F-fluorodeoxyglucose (FDG) has been used to beth detect and stage a variety of malignancies. The aim of this retrospective study was to evaluate the clinical value of 18F-FDG PET/CT for recurrence and metastasis in gastric carcinoma patients after total gastrectomy. Methods A total of 45 gastric carcinoma patients who underwent total gastrectomy were included. PET/CT scans were obtained for restaging. The " gold standard" of 18F-FDG PET/CT diagnostic accuracy was based on either histopathology or clinical follow-up. By using the t-test from SPSS 11.5, the cut-off of maximum standard-ized uptake values (SUVmax) from 18F-FDG to differentiate benign from malignant lesion at stomach were determined and calculated. Results (1) Of the 45 patients, 22 were suspicion recurrent lesion at stomach. Of the 22 patients, 12 were confirmed to have recurrent lesions. The diagnostic accuracy were 100.0% (12/ 12) for sensitivity, 70.0% (7/10) for specificity, and 86.4% (19/22) for accuracy, respectively. A higher SUVmax in malignant than benign lesion was noted (6.27 ± 3.42 vs 3.92 ± 2.24), though not reached to the significance (t = 1. 862, P > 0.05). (2) For extra-gastric lesion detection, the sensitivity, specificity, and accuracy for region lymph nodes were 78.9% (15/19), 92.3% (24/26), and 86.7% (39/ 45), for peritoneal spreading were 6/9, 97.2% (35/36), 91. 1% (41/45), and for distant sites were 86.7%(13/15), 93.3% (28/30), 91.1% (41/45). (3) False positive were found in eight sites. All were either inflammatory or physiological uptake at intestine. False negative were found in nine sites. Either due to small in size (less than 1.0 cm in diameter), well differentiation of the tumor cell or with a nature of signet ring. Conclusion 18F-FDG PET/CT had a potential to detect local, regional, and distant metastasis in gastric cancer.     

肺癌放疗后放射性肺损伤CT分级与正常组织并发症概率的关系

目的 探讨非小细胞肺癌 (NSCLC)三维适形放疗(3DCRT)后放射性肺损伤的CT分级与正常组织并发症概率(NTCP)的关系。方法 将3DCRT治疗后CT随访6个月以上的169例Ⅰ～Ⅲ期NSCLC患者按随访CT放射性肺损伤的表现分级并分为CT阳性组(2～4级)和CT阴性组(0、1级),复习全部病例的治疗计划,按全肺NTCP和患侧肺的NTCP分布各分为5组,对比分析放射性肺损伤CT分级与NTCP的关系。结果 不同CT分级的全肺和患侧肺NTCP值差异有统计学意义(全肺P=0.004,患侧肺P=0.000);全肺NTCP分组和患侧肺NTCP分组研究均显示患侧肺CT分级阳性率组间差异有统计学意义(全肺P=0.003,患侧肺P=0.000)。结论 NSCLC行3DCRT后放射性肺损伤的CT分级与NTCP密切相关。     

基于放疗中重复四维CT的食管癌大体肿瘤体积位移变化的比较研究

目的 基于重复四维CT (4DCT)模拟定位增强扫描探讨放疗中胸段食管癌原发肿瘤分次放疗内靶区位移变化。方法 29例胸段食管癌患者分别于放疗前及放疗10、20、30次时行4DCT模拟定位增强扫描,获得各时相原发肿瘤大体肿瘤体积(GTV)及内大体肿瘤体积(IGTV)。比较同次4DCT扫描所得胸上、中、下段食管癌GTV三维方向位移差异,各时段4DCT扫描所得同段食管癌GTV间同一方向位移差异及疗程中IGTV空间位置和体积变化。结果 胸中段患者初次及放疗20次时GTV位移在左右、前后、上下方向均不同(P=0.000~0.016),放疗10次时GTV位移上下与左右、前后方向均不同(P=0.000~0.006);胸下段患者初次及放疗10、20次时GTV位移上下与前后方向也不同(P=0.004~0.013);放疗疗程中不同治疗时段间GTV同一方向位移均相似(P=0.102~0.823)。疗程中IGTV空间位置变化不明显(P=0.689~0.999),而其体积在放疗20次时缩小最明显(P=0.012~0.029)。结论 放疗疗程中不同时段同一部位食管癌同一方向位移变化并不明显,尽管放疗20次时IGTV明显缩小但疗程中其空间位置变化不大。     

千伏X线平片测定自主呼吸控制和自由呼吸状态下保乳术后术腔中银夹位移的比较研究

目的 探讨适度深吸气呼吸控制(mDIBH)与自由呼吸(FB)两种状态下千伏(KV)X线平片测得术腔中选定银夹位移的差异及其两种呼吸状态下临床靶体积(CTV)外扩到计划靶体积(PTV)边界的差异.方法 比较mDIBH和FB状态下,同一选定银夹不同方向上位移的差异,不同选定银夹在同一方向上位移的差异,左右、头脚、前后各方向上CTV→PTVSb扩边界的差异性.结果 FB状态下,左右、头脚、前后方向最上层银夹与最下层银夹的位移不同[9.7mm与10.6mm(Z=-2.12,P=0.037)、7.3 mm与8.3mm(Z=-2.31,P=0.041)、15.5 mm与16.1 mm(Z=-2.32,P=0.041)],而最近胸壁层银夹与最外侧银夹位移相似[8.6 mm与10.6mm(Z=-0.27,P=0.754)、8.4 mm与8.3 mm(Z=-0.24,P=0.814)、15.7mm与16.5mm(Z=-0.26,P=0.856)];mDIBH状态下,每个银夹不同方向位移不同[5.0 mm与7.8 nun(Z=-2.31,P=0.036)、5.0 mm与9.3 mill(Z=-2.21,P=0.021)、7.8 nun与9.3 mm(Z=-2.11,P=0.041)].FB状态下,不同银夹在左右方向上的位移相似[10.6 mm与10.6 mm(Z=-0.24,P=0.815)],在头脚、前后方向上的位移不同[7.3 mill与8.4 mm(Z=-2.45,P=0.021)、15.5 mm与16.5 mm(Z=-2.41,P=0.043)];mDIBH状态下,不同银夹在左右方向上的位移不同[4.4mm与5.4 mm(Z=-2.31,P=0.031)],而在头脚、前后方向上的位移相似[8.6 mm与8.6 nlnl(Z=-0.21,P=0.815)、10.5 mm与10.8 mm(Z=-0.27,P=0.754)].FB与mDIBH状态间各银夹CTV→PTV外扩边界差异在左右、前后方向均不同[9.7 mm与5.0 mm(Z=-2.34,P=0.029)、15.5 mm与9.3 mm(Z=-2.31,P=0.021)],而在头脚方向上则相似[7.3 mm与7.8 mm(Z=-0.29,P=0.770)].结论 部分乳腺外照射的CTV→PTV靶区边界外扩应依据呼吸状态、边界位置及边界方向区别对待.     

基于锥形束CT的保乳术后调强放疗在线校正前后分次间位移规律分析

目的 基于锥形束CT（CBCT）探讨乳腺癌保乳术后调强放疗（IMRT）疗程中在线校正分次间位移变化规律。方法 选择保乳术后行全乳IMRT患者18例,共获取452次CBCT图像,获取CBCT校正前后分次间三维方向位移及摆位误差,分析分次间三维方向位移曲线。 结果 患者分次间位移幅度变化较大,同一患者不同方向的分次间位移幅度差异也较大。疗程中左右（LR）、前后（AP）和头脚（SI）方向分次间位移差异最大为0.22、0.49和0.48 cm,CBCT校正后LR、AP和SI方向位移差异最大为0.16、0.21和0.17 cm,CBCT在线校正降低了放疗疗程中患者SI方向的分次间位移（-0.08 cm 和0.03 cm,t=-2.373,P<0.05）和LR、AP、SI方向的随机误差（t=5.302、6.689、4.812,P<0.05）,系统误差差异无统计学意义。CBCT校正前后放疗疗程中患者分次间位移无明显规律性。结论 对于保乳术后IMRT患者,通过自动像素-解剖结构密度配准实施CBCT在线校正降低了放疗过程中患者头脚方向的分次间位移和三维方向的随机误差;由于个体差异性的存在,CBCT在线校正前后患者分次间三维方向位移离散度较大。