Preliminary study on the evaluation of olfactory neuroblastoma using PET/CT.

PURPOSE: Because of paucity of data available regarding the utility of PET/CT in the diagnosis and staging of patients with olfactory neuroblastoma (ONB), we retrospectively analyzed the efficacy of PET/CT in 9 patients with ONB. MATERIALS AND METHODS: Whole-body F-18 FDG PET/CT was performed in 7 patients with newly diagnosed ONB, as well as in 1 patient with recurrence and in 1 patient with remnant tumor. Regional C-11 choline (C-11 CHO) PET/CT was performed in 2 patients with negative F-18 FDG scans. The lesion with intense radiotracer uptake was suggested as positive for tumor and the results of PET/CT were compared with conventional staging examinations. RESULTS: F-18 FDG PET/CT was positive in 7/9 (77.7%) patients with ONB. In 2 patients with negative F-18 FDG, the lesions were C-11CHO avid. Both the primary tumors and its invasions were clearly delineated by F-18 FDG or C-11 CHO PET/CT. SUVmax of F-18 FDG in the primary tumor was 6.37 ± 4.22 and did not correlate with lesion size (F-18 FDG/size: r = 0.097, P = 0.820). Whole-body F-18 FDG PET/CT detected parapharyngeal and cervical lymph node metastases in 2 patients, lung metastases in 1 patient, liver metastases in 1 patients, and bone metastases in 2 patients. PET/CT altered the stages of 3 of 9 patients with upstaging in 2 patients and downstaging in 1 patient. CONCLUSIONS: PET/CT may be useful for the diagnosis and staging of ONB.

18F-FDG PET/CT for assessing therapeutic response to chemotherapy in patients with diffuse large B-cell lymphoma / 中华核医学杂志

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.

Comparison between 11 C-methionine and 18F-FDG PET/CT in diagnosing residual or recurrent glioma / 中华核医学杂志

Objective To assess the value of 11 C-methionine (MET) PET/CT for the diagnosis of residual or recurrent glioma in comparison to 18 F-FDG PET/CT. Methods Forty-six patients suspected of residual or recurrent glioma underwent both 11 C-MET and 18 F-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 stereotsctic 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) (x2 =19. 429, 1. 053, 15. 294, P ＜0.001, ＞0.05, ＜0.001 ), respectively. The T/G and T/W ratios of residual/recurrent giloma by 11 C-MET were significantly higher than those by 18 F-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 11 C-MET PET/CT is more sensitive and accurate than 18 F-FDG PET/CT for the detection of residual or recurrent glioma.

The value of ~(18)F-FDG PET/CT on the detection and staging of natural killer/T cell lymphomas / 中华核医学杂志

Objective To investigate the value of ~(18)F-fluorodeoxyglucose (FDG) PET/CT on the detection and staging of natural killer (NK)/T cell lymphomas.Methods Thirteen new and 2 recurrent csses of NK/T cell lymphoma were inchded in this study and they all underwent wllole-body ~(18)F-FDG PET/CT scans.A lesion with intense ~(18)F-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) ~(18)F-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 ~(18)F-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 ~(18)F-FDG-avid tumor.~(18)F-FDG PET/CT is an effective imaging tool for detection and staging of this disease.

Construction of a retroviral vector for RNA interference targeting human telomerase reverse transcriptase / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a recombinant retroviral vector for RNA interference targeting human telomerase reverse transcriptase (hTERT).</p><p><b>METHODS</b>The sequences coding for enhanced fluorescence protein (EGFP), U6 promoter and a small interfering RNA (siRNA) targeting hTERT were amplified by PCR, respectively, and sub-cloned sequentially into the retroviral shuttle plasmid pLXSN to construct the plasmid pLXSN-EGFP-U6-siTERT. The recombinant expression plasmid was identified by restriction enzyme digestion and sequencing. Fluorescence microscopy and flow cytometry were employed to analyze EGFP expression in NIH3T3 transfected with the recombinant plasmid, and MMT assay was performed to evaluate the growth inhibition of Hela cells resulting from RNA interference mediated by the plasmid.</p><p><b>RESULTS</b>Sequence analysis and restriction enzyme digestion showed that the recombinant expression plasmid pLXSN-EGFP-U6-siTERT was constructed successfully. Twenty-four hours after transfection of NIH3T3 cells with the recombinant plasmid, the expression rate of EGFP reached 24.1% as shown by flow cytometry. MTT assay demonstrated a cell death rate of 53.2% 72 h after transfection of Hela cells with the plasmid.</p><p><b>CONCLUSION</b>The successful construction of the recombinant retroviral plasmid mediating potent cell growth inhibition suggests the great potential of RNA interference technique in suppressing hTERT expression in mammalian tumor cells.</p>