[en] PET-CT is a good modality for localization of the malignant lesions. It is superior to PET in the diagnosis, localization and guiding treatment for head and neck cancer. Possessing of the superiority of PET and CT, PET-CT can improves the accuracy and confidence for diagnosis and staging and helps to reliably distinguish malignant lesions from physiologic uptake and some inflammation. It is also helpful for guiding more accurate radiotherapy. Although PET-CT has a lot of superiorities, it still has come shortcomings in the diagnosis of the thyroid cancer, parotid gland tumor and in the discriminating malignancy from some active inflammation. (authors)

[en] In this paper we discuss the value of ¹⁸F-FDG PET/CT on the TNM staging of colorectal cancer before surgery. Forty-one patients diagnosed with colorectal cancer from surgery were examined by ¹⁸F-FDG PET/CT. PET/CT findings were compared with post-operative pathology. The sensitivity of colorectal cancer was 97.6% by PET and 100% by PET/CT. The diagnostic accuracy of T-stage and N-stage and metastasis and TNM-stage before operation in colorectal cancer were 85.4%, 85.4%, 97.6% and 75.6% respectively, and the correlation with surgical appearances and pathological findings were 0.574, 0.670, 0.918 and 0.664 respectively, all P<0.01. Good correlation exists between manifestations on PET/CT and operative pathology. PET/CT may become a good choice diagnostic modality for pre-treatment staging evaluations of colorectal carcinomas. (authors)

[en] Objective: To study the clinical value of ¹¹C-methionine (MET) PET/CT imaging in brain glioma. Methods: 27 cases were studied including 2 glioma, 23 operated glioma and 2 healthy volunteers. ¹¹C-MET PET/CT was performed in all cases but ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in only 17 cases. Follow-up period was within 3-17 months. Results: ¹¹C-MET was negative in 4 cases and ¹⁸F-FDG negative in 3 cases in group without remnant or recurrent tumor after operation. In 2 cases of initial glioma and 19 cases with remnant or recurrent tumor group, ¹¹C-MET imaging was positive in 20 cases, tumor/gray matter ratio and tumor/white matter ratio were 2.02 ± 0.96, 3.01 ± 1.79, respectively, among them 14 cases also with ¹⁸F-FDG imaging showed positive in 12 cases. Lesions showed by ¹¹C-MET were far more clear than that of ¹⁸F-FDG. Also tumor/gray matter ratio and the tumor/white matter ratio of ¹¹C-MET imaging were significantly higher than ¹⁸F-FDG (2.15 ± 1.16 vs 0.97 ± 0.43, P<0.01; 3.31 ± 2.16 vs 1.90 ± 0.67, P<0.05 ). Conclusion: ¹¹C-MET PET/CT is superior to ¹⁸F-FDG PET/CT in the diagnosis and localization of brain glioma. (authors)

[en] Objective: To conjugate galactose streptavidin (SA-gal) and use it as a clearing agent in pre-targeting radioimmunoimaging (RII) of colon carcinoma xenograft models. Methods: SA-gal was obtained by incubating galactose moiety with streptavidin at a molar ratio of 45 : 1. For imaging in vivo, biotinylated antibody radiolabelled with ¹³¹I was injected into the nude mice bearing the colon carcinoma xenograft via the tail vein. 24 h later, SA-gal were intraperitoneally injected at a ratio of 10-fold (molar) excess to antibody. At 0.5 h and 6 h after SA-gal administration, the animals of different test groups were killed for biodistribution study or imaging. No clearing agent was administrated to the animals of two control groups and they were also killed for biodistribution study or imaging at 24 h or 30 h after injection of ¹³¹I labelled antibody. Results: 1) Galactose moiety was bound to SA at a molar ratio of 20 : 1. 2) In pre-targeting RII, SA-gal undertook the chase effect very fast. At 0.5 h after injection, the blood level of radioactivity decreased very fast and tumor-to-blood (T/B) ratio increased from 0.32 to 1.44. At 6 h after SA-gal administration, T/B ratio reached 5.23, significantly higher than 0.41 of the control group (P<0.001), and the tumor was imaged clearly. At 0.5 h after SA-gal administration, a large increment in liver radioactivity was seen accompanying with a rapid decrease of blood radioactivity. Conclusion: SA-gal can considerably improve T/NT ratio and offer better early tumor images and it is a favorable clearing agent in ¹³¹I-biotinylated antitumor antibody RII

[en] Objective: The aim of this study was to evaluate the clinical role of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT for detection of recurrent and (or) metastatic tumor in patients with rising serum alpha fetoprotein (AFP) after the management of hepatocellular carcinoma (HCC). Methods: The whole body ¹⁸F-FDG PET/CT scans were performed in 123 patients with rising serum AFP [(3554.49 ± 1663.08) μg/L; normal level: 0-8. 1 μg/L] on routine follow-up examinations after the management of HCC. All PET and CT images of one patient were fused by the specific software on workstation. PET images, CT images and PET/CT fused images were analyzed by frame to frame. All patients were followed up for more than six months. The final diagnosis was obtained by pathologic finding from surgery or biopsy, and (or) multi-modalities of imaging and clinical follow-up. Chi-Square test for statistics was used with SSPS 11.5 software. Results: There were 111 patients proved to be suffered with recurrent and (or) metastatic tumor. Intrahepatic lesions were found in 84 patients; extrahepatic lesions were found in 65 patients. The overall sensitivity of ¹⁸F-FDG PET/CT for tumor detection was 87.4% (97/111) and it was obviously higher than 70.3% (78/111) of ¹⁸F-FDG PET alone (χ²=9.744, P=0.002). The specificity, accuracy, positive predictive value and negative predictive value of ¹⁸F-FDG PET/CT was 83.3% (10/12), 87.0% (107/123), 98.0% (97/99) and 41.7% (10/24), respectively. The PET and CT were complement in the lesions detection. In 9 patients proved as well-differentiated HCC, the sensitivity of ¹⁸F-FDG PET/CT was 5/9, which was lower than that of overall sensitivity (χ²=6.616, P=0.01). Conclusions: ¹⁸F-FDG PET/CT is a valuable imaging tool to detect the recurrent and (or) metastatic tumor in patients with rising serum AFP after HCC treatment. Nevertheless, a pitfall of false-negative could be happened in patients with well-differentiated HCC. (authors)

[en] Objective: To evaluate the clinical value of PET/CT on the diagnosis and staging of lung cancer. Methods: 46 lung cancer patients including 35 pre-treatment and 11 post-treatment cases. PET/CT fusion images, PET images and CT images of the same patient were analyzed frame by frame. Results: 1) The sensitivity of PET/CT in 35 pre-treated cases reached 100%. Except one case of alveolar carcinoma showed a diffuse uptake in both lungs, the other patients displayed as hypermetabolic nodular or mass lesions with the size around 0.8-9.4 cm and the standardized uptake value (SUV) 4.6 ± 1.94. The position of hypermetabolic lesion of PET finding were all concordant to CT. PET/CT was superior to PET and CT in final diagnosis, delineating the border, detecting tumor invasion and in differentiating lung cancer from atelectasis, obstructive pneumonitis and pleural effusion. Among 11 post-treated cases, no malignancy was seen in 9 cases and in two cases with metastases in both lungs, the lesions were detected definitely by PET/CT. 2)For the staging, PET/CT was also superior to PET and CT alone with the sensitivity of 95.2%(PET/CT), 90.4%(PET), 73.8%(CT) respectively. PET and CT were complemental each other in the detection of the lesions. Obviously, PET was superior to CT in detection of small lymph node metastases, pleura, bone and adrenal metastases. CT was better than PET in detection of small lung metastases. Conclusions: PET/CT is superior to PET and CT alone in the diagnosis and staging of lung cancer. PET and CT can complement each other. (authors)

[en] To investigate the improved clearance effect of avidin (Av) and streptavidin-gal (SA - gal) for blood radiolabeled biotinylated antibody in pre-targeting radio-immuno therapy (RIT) of colon carcinoma xenograft models. Biotinylated antibody radiolabeled with ¹³¹I was injected into the nude mice bearing the colon carcinoma via the tail vein. 24 h later, in 2 test groups, SA-gal or Av at a 10 - fold molar excess of antibody was intraperitoneally injected into the animals whereas no any chase agents were given to the control animals. Animals were killed for biodistribution study at 30h after ¹³¹I-labelled biotinylated antibody administration. Results showed that Av and SA-gal took the effect of chase very fast. At 6h after injection, the blood level of radioactivity decreased very fast. The tumor/blood ratios of control group, Av chase group, SA-gal chase group were 0.42, 2.09, 5.23 respectively, P < 0.05 and P < 0.01 for the latter two groups as compared other control groups. Compared with Av, SA-gal showed better chase effect, its T/B ratios was 5.23, significantly higher than 2.09 of Av (P < 0.01). In the tissue biodistributions, relatively high non-specific radioactivity uptakes in non-liver organs were seen in Av chase group. Utilized in pre-targeting RIT, both Av and SA-gal could make the blood level of radioactivity decrease quickly and considerably improves tumor T/NT ratios. The chase effect of SA-gal was superior to that of avidin

[en] Objective: The aim of this study was to evaluate the clinical role of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in detection of malignant melanoma. Methods: The whole body ¹⁸F-FDG PET/CT scans were performed on 61 patients with malignant melanoma. All PET and CT images of one patient were fused by the specific software on workstation. PET images, CT images and PET/CT fused images were analyzed by frame to frame. All patients were followed up for at least six months or last to the patient death. The final diagnosis was obtained by pathologic finding horn surgery or biopsy, and (or) multi-modalities of imaging and clinical follow-up. Results: The overall sensitivity, specificity and accuracy of ¹⁸F-FDG PET/ CT for detecting primary malignant melanoma was 90.9% (40/44), 88.2% (15/17) and 90.2% (55/61), respectively. In 9 patients post local surgery and proven histologically malignant melanoma, ¹⁸F-FDG PET/ CT detected the residual and metastatic tumor in 3/5 and 4/4 eases, respectively. In 7 patients with metastastic melanoma, ¹⁸F-FDG PET/CT found primary tumors in 2 eases and metastatic foci in 4 eases. In 33 patients after the radical operation, the sensitivity, specificity and accuracy of ¹⁸F-FDG PET/CT for detecting recurrence or metastasis was 100.0% (19/19), 85.7% (12/14) and 93.9% (31/33), respectively. Of these 33 patients, 16 (48.5%) were up-staged and 7 (21.2%) were down-staged by ¹⁸F-FDG PET/ CT. Conclusion: ¹⁸F-FDG PET/CT is a valuable imaging tool to detect the residual, recurrent and metastatic tumor in patients with malignant melanoma. (authors)

[en] Objective: To assess the value of ¹⁸F-fluorodeoxyglucose (FDG) PET imaging in localizing the epileptic foci and its use in surgical therapy. Methods: PET brain imaging was performed in 110 patients with primary epilepsy. The images were analyzed by visual inspection and semi-quantitative measurement. The scalp electroencephalogram (EEG) was examined in all patients, among whom electrocorticogram (ECoG) or depth electroencephalogram (DEEG) was examined in 26 cases and MRI and(or) CT were performed in 66 cases. In 110 cases, temporal lobectomy was performed in 17 patients and X-ray or γ knife therapy was performed in 69 cases. The duration of follow-up lasted at least 1 year. Results: 88.2% cases had abnormal PET imaging among 110 cases including 94.8% hypometabolic foci and 5.2% hypermetabolic foci. PET was more sensitive than EEG and MRI (88.2%, 67.3% and 43.5% respectively, χ² were 13.88 and 24.17, all P <0.01). PET detected solitary lesion well in 60.8% patients, the result was also more sensitive than EEG (60.8% vs 35.1% , χ²=11.08, P<0.01). Compared with ECoG or DEEG, the sensitivity and accuracy of PET to localize the epileptic foci were 92% and 87%. 17 patients treated by temporal lobectomy and 69 patients by X-ray or γ knife therapy guided with PET, all got satisfactory results. Conclusion: ¹⁸F-FDG PET imaging is a sensitive modality in localizing epileptic foci and also useful to guide surgical and orientation radiation therapy. (authors)

[en] Objective: To evaluated the value of PET conventional parameters and texture parameters in prediction of the Kirsten rat sarcoma viral oncogene (KRAS) gene expression status in colorectal cancer (CRC) by analyzing the relationship between those parameters and KRAS gene status. Methods: From December 2012 to January 2017, ¹⁸F-fluorodeoxyglucose (FDG) PET/CT data and KRAS gene status of 58 CRC patients (40 males, ¹⁸Females, average age 56.31 years) before anti-tumor therapies were collected. The relationship between PET parameters and KRAS gene expression was analyzed. Receiver operating characteristic (ROC) curve analysis was used to evaluate the values of PET conventional parameters and texture parameters for predicting the KRAS gene status. Spearman rank correlation and Mann-Whitney u test were used to analyze the data. Results: of 58 CRC patients, 19 (32.8%) had KRAS mutation, while 39 (67.2%) were with wild type KRAS. Among the 46 PET image parameters extracted by Chang-Gung image texture analysis (CGITA), 14 PET image parameters were selected by Spearman rank correlation (all |r_s| > 0.8), including 12 texture parameters and 2 conventional parameters (maximum standardized uptake value (SUV_max) and total lesion glycolysis (TLG)). Six PET image parameters (4 texture parameters and 2 conventional parameters) were found to be different between KRAS gene mutant group and wild group (u values: from -4.481 to -2.046, all P < 0.05). Among the 4 texture parameters, standardized uptake value (SUV) kurtosis (SUV_kur) had the best prediction value, while SUV_max was the better one for prediction in the 2 conventional parameters. When 4.27 was selected as the cut-off value for SUV_kur , the Youden index was up to the maximum as 0.35 and it yielded 0.667 on the area under curve (AUC) (95% CI: 0.517-0.816, P = 0.041) with the sensitivity of 15/19 and specificity of 56.4% (22/39), respectively. When 16.6 was selected as the cut-off value of for SUV_max , the Youden index was up to the maximum as 0.64 and the AUC on predicting the KRAS mutant was 0.865 (95% CI: 0.770-0.960, P < 0.001) with the sensitivity of 17/19 and specificity of 74.4%(29/39), respectively. The efficacy of SUV_max for predicting KRAS mutation was significantly better than that of SUV_kur (z = 3.258, P = 0.001). Conclusion: PET texture parameters and conventional parameters can be used to predict the KRAS gene status in CRC patients, and SUV_max may be the best parameter. (authors)