| Background and objectiveLung cancer is the leading cause of death of malignant tumors. At present, non small cell lung cancer accounts for about 80% of all lung cancer, about 75% of the patients found already at an advanced stage, the five-year survival rate is low, prognosis is poorer. The treatment methods include surgery, radiotherapy and chemotherapy. For la because of medical reasons for inoperable patients (serious medical diseases, elderly patients, refused surgery, etc.) and stage III inoperable patients radical chemoradiotherapy; I or B II because of medical reasons for inoperable patients with No recommended received radical radiotherapy, the high-risk patients followed by adjuvant chemotherapy (Group 2B), N1 patients recommended received radical radiotherapy. For the implementation of radiotherapy patients, the range of lesions is crucial to the accuracy of target setting. At present, most clinical with CT or MRI results as conventional radiotherapy on the basis of sketch. But when NSCLC some complicated with atelectasis, pleural effusion, or obstructive pneumonia complications. CT is difficult to judge the boundary of the tumor, and the true lesions have great difference, so according to the formulation of the target area of the tumor radiotherapy plan will affect the prognosis of patients with. And PET/CT as the boundary of a functional, anatomical imaging, by the PET imaging can provide information of molecular lesions in detail the function and metabolism, precise anatomical localization of lesions with CT imaging can well distinguish between tumor and non tumor tissue and provide more accurate information for the next treatment. This study aims to investigate the application value of 18F-FDG PET/CT in non-small cell lung cancer in radiotherapy..Materials and methods1 General informationIn accordance with the 2014 NCCN guidelines "collected in our hospital in 2010 January to December 2014 of 20 patients with non small cell lung cancer patients, and no prior radiotherapy. Inclusion criteria:(1) complete medical history, physical examination findings and clinical staging required for conventional imaging data; (2) tumor lesions for 1-2; (3) lung cancer first, with or without lymph node enlargement; (4) with tumor radiation therapy indications. Male 15 cases, female 5 cases, aged 38 to 76 years (median age 57 years). Were confirmed by pathology or cytology confirmed NSCLC, which squamous cell carcinoma (SCC) in 16 cases,4 cases of adenocarcinoma; primary tumor site distribution:1 case of left lung lobe in 8 cases, left lower lung lobe in 2 cases, right pulmonary lobe (4 cases), right pulmonary lobe in 5 cases and mediastinal type. Lymph node metastasis:12 distribution of hilar and mediastinal leaf between 9,26,6 and 3 other regions of the supraclavicular (muscle)2 chest CT examinationAll patients use American GE Dis-86 750 HDCT for routine chest plain scan, scan range from the thoracic inlet to the diaphragm muscle level, including the whole lung field. Scanning parameters:tube voltage of 120 kVp, automatic tube current, noise figure 12, rotating frame 0.6 per week, pitch 0. 984, bed speed 39.37 mm/week, a thick layer of spacing layer and are 5 mm, scanning the vision 400 mm x 400 mm. And by experienced two radiology oncology physicians jointly by the sketch layer lung primary lesions and lymph node range, gtvct tumor volume.3 18F-FDG PET/CT examinationThe instrument for Siemens company Biograph Truepoint 64 (PET/CT 52). The PET detector for 52 ring lutetium oxyorthosilicate, total 32448 detection unit, the axial field of view (axial FOV) range for 216mm, the axial resolution is 2mm. With the 64 layer data acquisition system with CT matching (DAS), instant time resolution of 83ms. Imaging agent for 18F-FDG,18F produced by Japan’s Sumitomo HM-20 medical cyclotron and 18F-FDG by Pat Beijing Science and Technology Co., Ltd. PET-FDG-IT-1 automatic synthesis modules for production, radiation chemical purity of 95%. After the first CT scan capture, determine the CT and PET scanning range, in the shallow breathing state complete CT scanning and image reconstruction, then the PET image acquisition range with CT. PET image by attenuation correction, iterative reconstruction, multi level, multi amplitude imaging. After scanning PET and CT images to the image workstation, image fusion and 3D reconstruction. Will PET/CT imaging and CT images were transmitted to the radiotherapy planning system, PET/CT imaging guided radiotherapy target volume delineation, in accordance with the SUVmax>2.5 as standard, by two nuclear medicine physicians outlining common pulmonary primary lesion range, in the PET/CT images to calculate the primary tumor volume GTVPET/CT.4 statistical processingUsing SPSS software to obtain the results of statistical analysis, t-test analysis of 18F-FDG PET/CT and CT to delineate the GTV and different pathological types of GTV has no difference. P<0.05 said the difference was statistically significant.Results1.GTVct and GTVPEt of 20 patients have different degree of difference. GTVCT (133.0519.21) cm3, GTVPEr (119.75+17.83) cm3, both comparative difference was statistically significant(P<0.05); One of the three patients GTVPET/CT GTVCT increased by 18.1%,17 patients GTVPET GTVCT shrink 14.3% relatively.2. TNM staging change:20 cases of 3 patients with 18F-FDG PET/CT check M installment up discovered the sternum, ribs and vertebral metastases, its from radical radiotherapy to palliative radiotherapy treatment; F-FDG PET/CT is more than CT found 7 lymph nodes metastasis, (detailed) make up 4 cases N staging of patients from surgery to radical radiotherapy treatment.3. Different tumor histologic types in CT and 18F-FDG PET/CT in GTV difference:by tumor histological type classification, this study cases squamous carcinoma and adenocarcinoma group.Conclusion1.20 cases of patients with NSCLC GTVPET/CT mean (21.31+13.81 cm3) than the gtvct (24.18 ± 14.85 cm3) is small, the difference has statistical significance (P< 0.05). GTVPET/CT is GTVCT average rate was 12.38%. Including 4 cases of GTVPET/CT patients is greater than GTVCT,16 cases of GTVPET/CT less than GTVCT-2. According to the histological classification, the study of case group adenocarcinoma and squamous cell carcinoma group, the results are shown in table 2. Table 2 18F-FDG and PET/CT difference CT guided radiotherapy target range delineation and tumor histological type.3.20 cases of non small cell lung cancer patients, according to the results of 18F-PET/CT imaging and 45%(9/20) of patients with stage occurred the change:up staged in 5 cases, where N staging in 2 cases, M stage in 3 cases; stage decreased in 3 cases,2 cases dropped from T3 to T2,1 case from T4 drop to T3.3 cases of M stage patients increased 18F-FDGPET/CT were found the sternum, rib and vertebral metastases, the diagnosis and treatment of the disease from radical radiotherapy for palliative radiotherapy; 18F-FDG PET/CT compared with CT and found two lymph node metastasis,2 cases of N up points the treatment period rose from surgery to radiotherapy. |
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