[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: 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 explore the value of ¹⁸F-FDG PET/CT on the assessment of chemotherapy response in patients with diffuse large B-cell lymphoma (DLBCL). Methods: ¹⁸F-FDG PET/CT was performed before and after 4 cycles of chemotherapy (R-CHOP or CHOP protocol) in 53 patients with DLBCL. The patients were divided into 3 groups: complete response group, partial response group and no response group. The therapeutic response was assessed by comparing post-treatment ¹⁸F-FDG PET/CT with pre-treatment PET/CT. Complete remission (CR) rate at the end of chemotherapy was calculated. χ² test was performed with software SPSS 13.0. Results: CR rates of complete response group, partially response group and no response group were 88.5% (23/26), 73.3% (11/15) and 8.3% (1/12), respectively (χ²=23.548, P=0.000). CR rates of the complete and partially response groups were significantly higher than those of no response group (χ²=22.656, P=0.000; χ²=11.407, P=0.001). Conclusion: ¹⁸F-FDG PET/CT may be useful for the assessment of chemotherapy response in DLBCL. (authors)

[en] Objective: To assess the value of ¹¹C-methionine (MET) PET/CT for the diagnosis of residual or recurrent glioma in comparison to ¹⁸F-FDG PET/CT. Methods: Forty-six patients suspected of residual or recurrent glioma underwent both ¹¹C-MET and ¹⁸F-FDG PET/CT within 5-day interval. The glioma was considered as positive on PET/CT images based on (1) visual judgment of higher tracer uptake compared with the normal gray matter; (2) semiquantitative analysis of tumor to contralateral normal gray matter (T/G) and contralateral normal white matter (T/W) ratios. The diagnosis was confirmed by stereotactic biopsy or radiological findings of MRI or CT and clinical follow-up (>6 months). The Chi-square test and paired t test were used for statistical analysis. Results: Residual or recurrent glioma was confirmed in 36 patients. The sensitivity, specificity, accuracy of ¹¹C-MET and ¹⁸F-FDG PET/CT were 94.4% (34/36) vs 47.2% (17/36), 90.0% (9/10) vs 100% (10/10), 93.5% (43/46) va 58.7% (27/46) (χ²=19.429, 1.053, 15.294, P<0.001, >0.05,<0.001), respectively. The T/G and T/W ratios of residual/recurrent glioma by ¹¹C-MET were significantly higher than those by ¹⁸F-FDG (T/G ratio: 1.68 ± 0.23 vs 1.13 ±0.51, t=5.877, P<0.001; T/W ratio: 2.52 ± 0.28 vs 1.42 ± 0.57, t=10.470, P<0.001). Conclusion: ¹¹C-MET PET/CT is more sensitive and accurate than ¹⁸F-FDG PET/CT for the detection of residual or recurrent glioma. (authors)

[en] Radiopharmaceutical of ¹⁸F-FHBG was synthesized and recombinant expression plasmid pLXSN-tk was constructed. The nude mice sub-skin model transplanted with human liver cancer was constructed by subcutaneous implantation of cultured the BEL-7402 liver carcinoma cell lines into the two sides axillary fossa nude mice. The left tumors were used as the control, while the right tumors were used as the experiment group, with the cancer cell being transfected by the pLXSN-tk. PET images were taken at 10, 30, 50, 70, 90, 110, 130, 150, 170, 190 and 210 min after ¹⁸F-FHBG injection via the tail veins. The results show that the uncorrected radiochemical yield of ¹⁸F-FHBG was 4%-10% and the radiochemical purity was over 95%. The ¹⁸F-FHBG PET images indicated that ¹⁸F-FHBG uptake of the control did not increase obviously, whereas high activity was observed in the experiment group 50-210 min after ¹⁸F-FHBG injection. ¹⁸F-FHBG uptake of the experiment group increased gradually to 19.772 kBq·mL^-1 150 min after ¹⁸F-FHBG injection, where the experiment/control tumor ratio was peaked at 4.99. The results indicated that ¹⁸F-FHBG PET imaging of HSV1-tk expression in tumors can be used to monitor, in living animals, and expression of theoretical gene. (authors)

[en] Background: PET with "1"8F-FDG has been considered of limited value for the detection of bladder cancer because of the urinary excretion of the tracer. Purpose: To investigate the clinical value of dual phase "1"8F-FDG PET/CT with oral diuretic in the diagnosis of bladder cancer. Methods: 107 patients with suspected bladder cancer were enrolled in the present study from May, 2003 to May, 2012. Each patient underwent the whole body "1"8F-FDG PET/CT scans routinely. After that, all patients received the forced diuresis by orally administration of furosemide (40 mg) and drinking a lot of water. Two hours later, after several times of urination, the patients underwent an additional delayed pelvic PET/CT scans. The intravesical radioactivity was compared between the routine and delayed the scans and the visualization of the tumor was evaluated. The diagnostic efficacy was determined based on the pathological examinations and the clinical following-up. Results: With the forced diuresis, intravesical "1"8F-FDG activity decreased significantly in 96.3% of the patients. The lesions on the wall of urinary bladder were visualized clearly in the delayed PET images, which weren't seen in the rout/ne PET images. "1"8F-FDG PET/CT was positive in 75 patients who all then received the operation. 69 patients were diagnosed pathologically to have the bladder cancer and 6 patients to have benign diseases. "1"8F-FDG PET/CT was negative in another 32 patients. Four patients of them were then diagnosed to be bladder cancer. Another 28 patients were clinically followed up more than 6 months and none of them was found to have bladder cancer. The sensitivity, specificity and accuracy of the dual phase PET/CT imaging for diagnosing the bladder cancer were 94.5%(69/73), 82.4%(28/34) and 90.7%(97/107), respectively. Conclusion: The forced diuresis using oral furosemide can significantly reduce the intravesical radioactivity and improve the detectability of "1"8F-FDG PET/CT for the bladder cancer. (authors)

[en] Objective: To investigate the value of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT on the detection and staging of natural killer (NK) /T cell lymphomas. Methods: Thirteen new and 2 recurrent cases of NK/T cell lymphoma were included in this study and they all underwent wllole-body ¹⁸F-FDG PET/CT scans. A lesion with intense ¹⁸F-FDG uptake was taken as positive for disease involvement and semiquantitative metabolic assessment was performed with the maximum standardized uptake value (SUV_max). All patients were followed for more than 6 months. The t-test was used to analyze the semi-quantitative data statistics. Results: (1) ¹⁸F-FDG PET/CT had 100% positive detection rate for NK/T cell lymphom. Of 11 cases with disease involvement of the nasal region. PET/CT detected 10.either in the nasal cavity or in the nasopharynx, 6 with extra-nasal infiltration, and 7 with regional nodal metastasis. There were 4 non-nasal cases and PET/CT detected one or multiple extra-nasal lymphoma lesions. The SUV_max of nasal and extra-nasal lesions was 12.42 ± 9.25, 9.54 ± 7.12, respectively, with no significant difference (t=1.120, P>0.05). (2) Two cases (2/15) diagnosed of this disease by PET/CT were initially referred as investigation of fever of unknown origin. For the remaining 13/15 known cases, PET/CT detected more 'unsuspected' lymphoma lesions in 7 cases and affected the staging in 6 patients. The ¹⁸F-FDG uptake (SUV_max)of I-II stage patients was mildly lower than that of III-IV stage patients, but no significant difference was observed (t=0.757, P>0.05). Conclusions: NK/T cell lymphoma is an intensely ¹⁸F-FDG-avid tumor. ¹⁸F-FDG PET/CT is an effective imaging tool for detection and staging of this disease. (authors)

[en] [${}^{18}$F]FAPI-42 is a new fibroblast activation protein (FAP)-specific tracer used for cancer imaging. Here, we describe the optimal acquisition time and in vivo evaluation of [${}^{18}$F]FAPI-42 and compared intra-individual biodistribution, tumor uptake, and detection ability to [${}^{68}$Ga]Ga-FAPI-04. A total of 22 patients with various types of cancer received [${}^{18}$F]FAPI-42 whole-body positron emission tomography/computed tomography (PET/CT). Among them, 4 patients underwent PET/CT scans, including an early dynamic 20-min, static 1-h, and static 2-h scans. The in vivo biodistribution in normal organs and tumor uptake were semiquantitatively evaluated using the standardized uptake value (SUV) and tumor-to-background ratio (TBR). Furthermore, both [${}^{18}$F]FAPI-42 and [${}^{68}$Ga]Ga-FAPI-04 PET/CT were performed in 12 patients to compare biodistribution, tumor uptake, and tumor detection ability. [${}^{18}$F]FAPI-42 uptake in the tumors was rapid and reached a high level with an average SUVmax of 15.8 at 18 min, which stayed at a similarly high level to 2 h. The optimal image acquisition time for [${}^{18}$F]FAPI-42 was determined to be 1 h postinjection. For tumor detection, [${}^{18}$F]FAPI-42 had a high uptake and could be clearly visualized in the lesions. Compared to [${}^{68}$Ga]Ga-FAPI-04, [${}^{18}$F]FAPI-42 had the same detectability for 144 positive lesions. In addition, [${}^{18}$F]FAPI-42 showed a higher SUVmax in liver and bone lesions (P < 0.05) and higher TBRs in liver, bone, lymph node, pleura, and peritoneal lesions (all P < 0.05). The present study demonstrates that the optimal image acquisition time of [${}^{18}$F]FAPI-42 is 1 h postinjection and that [${}^{18}$F]FAPI-42 exhibits comparable lesion detectability to [${}^{68}$Ga]Ga-FAPI-04.