FDG PET may be useful for differentiating common enhancing malignant brain tumors, particularly lymphoma versus high-grade glioma and metastatic tumor. FDG PET can provide useful information for distinguishing between lymphoma and other malignant enhancing brain tumors and is recommended when differential diagnoses are difficult to narrow using MRI alone.

Key words: GLUT-1; positron emission tomography; [F-18]-fluorodeoxyglucose; standardized uptake value; ovarian cancer; biomarkerOvarian cancer is locally aggressive and often disseminates to distant sites. 1 For all stages, the 5-year survival rate is only 46%. 2 Treatment planning depends on information regarding the presence or absence of metastases, the local situation and the malignant activity of the primary tumor. In general, anatomic imaging has been the fundamental approach to cancer imaging, and its daily use has been supported in the management of individual patients with cancer. In ovarian cancer, chest and abdomen CT is used to screen for metastases and MRI is used to assess the local situation.However, anatomic imaging methods for cancer management are of limited value, due to the difficulty in predicting whether the tumor will respond to chemotherapy in patients with ovarian cancer. Treatment other than primary debulking surgery for cancer of the ovary has been proposed as patients with bulky, nonresectable disease do not benefit from primary surgery. 3,4 Analysis of therapeutic outcome in patients with advanced cancer of the pancreas and esophagus provides clear evidence that neoadjuvant chemotherapy before surgery enables downstaging, thereby improving the operability as well as the prognosis of patients. 5,6 In an advanced ovarian cancer study, Kuhn et al. 7 reported that neoadjuvant chemotherapy apparently improved patient prognoses. Thus, early detection of tumor response to chemotherapy would be useful in determining whether such an approach is suitable for ovarian cancer patients.For assessment of malignant activity (which is a biomarker of response to chemotherapy, prognosis and overall chance of survival in ovarian cancer patients), measurement of viability and grading of tumors, 8 -10 cell proliferation 11-13 and glucose metabolism 14,15 are instructive. However, these assessments are performed using tissue specimens, requiring laparotomy for a biopsy or resection of ovarian tissue, which is subject to tissue sampling errors. A noninvasive in vivo imaging technique to assess malignant activity and gain prognostic information of ovarian tumors may be more accurate, as well as provide a more acceptable alternative for patients initially reluctant submit to minor surgery.FDG-PET is a unique, noninvasive method for studying biochemical and metabolic changes in cancer tissue. 16 FDG uptake has been correlated with tumor proliferation rate, tumor grade and expression of glucose transporters, which are biomarkers of the response to chemotherapy and the prognosis and overall chances of survival in cases of malignant disease. 16 -20 Our aim was to determine whether FDG-PET is useful for the assessment of malignant activity and the gathering of prognostic information in ovarian cancer. We compared FDG uptake, quantified as an SUV, with clinical stage; tumor grade of cells, assessed by HE staining; and cell proliferation and glucose metabolism, assessed by immunohistochemistry (MIB-1 LI and inten...

(18)F-FDG PET is considered to be useful for the diagnosis and evaluation of disease activity along with HRCT findings, and in monitoring response to chemotherapy in patients with PM.

Osteoporosis represents a significant side effect of glucocorticoid therapy, and alendronate has been reported to prevent this glucocorticoid-induced osteoporosis. Functional imaging with 18 F-fluoride PET allows quantitative analysis of bone metabolism in specific skeletal regions. However, only a few studies have quantitatively determined bone turnover and metabolism in glucocorticoid-induced osteoporosis by radiologic imaging techniques including PET. The aim of this study was to examine changes in regional bone remodeling and turnover as measured by 18 F-fluoride PET, the relationship between these measured changes and conventional bone metabolism parameters, and the effect of alendronate treatment. Methods: The study group consisted of 24 postmenopausal women (mean age, 59.7 y) who had various diseases, excluding rheumatoid arthritis, and had been treated with 10 mg or more of oral glucocorticoids (prednisolone equivalent) per day for more than 6 mo. Treatment with 5 mg of alendronate per day began at the time of study entry and continued for 12 mo. 18 F-fluoride PET was performed at baseline, 3 mo, and 12 mo to determine localized bone turnover, and the results were compared with other bone metabolism parameters. Results: Lumbar spine standardized uptake values (SUVs) were significantly lower (P , 0.05) in the osteoporotic group (T-score # 22.5) than in the group that was healthy or osteopenic (T-score . 22.5). Patients treated with alendronate for 12 mo exhibited significant decreases in serum bone-specific alkaline phosphate (P , 0.05), urinary N-telopeptide for type I collagen (P , 0.01), lumbar spine SUV (P , 0.01), and femoral neck SUV (P , 0.01) in association with a gradual increase in bone mineral density (BMD) of the lumbar spine relative to the baseline value (P , 0.05). Although there was a significant correlation between BMD and SUV in the lumbar spine at baseline (P , 0.05), there was no correlation between the 2 variables at 12 mo of treatment with alendronate. Conclusion: Alendronate treatment resulted in significant decreases in bone metabolism and turnover in the lumbar spine. It also led to an increase in BMD of the lumbar spine in patients with glucocorticoid-induced osteoporosis. Our findings suggest that antiresorptive therapy has a direct bone-metabolism effect on skeletal kinetics in glucocorticoid-induced osteoporosis at the clinically important site of the lumbar spine.

The grade of histologic differentiation is one of the most important prognostic factors in patients with endometrial carcinoma and postoperative staging. The aim of this study was to investigate whether 16a-18 F-fluoro-17b-estradiol ( 18 F-FES) and 18 F-FDG PET reflect clinicopathologic features in patients with endometrial tumors. Methods: A total of 22 patients with endometrial adenocarcinoma and 9 with endometrial hyperplasia (mean age, 56.0 6 15.3 y) underwent 18 F-FES PET for estrogen receptor imaging and 18 F-FDG PET. Regional values of tracer uptake were evaluated using standardized uptake value (SUV) and the SUV ratio of 18 F-FDG to 18 F-FES. The accuracy for predicting tumor aggressiveness defined as high-risk carcinoma (International Federation of Gynecology and Obstetrics [FIGO] stage $ Ic or histologic grade $ 2), low-risk carcinoma (FIGO stage # Ib and grade 1), and hyperplasia was compared for each PET parameter using receiver-operating-characteristic (ROC) analysis. The diagnostic accuracy of MRI findings for clinical staging was also compared. Results: Although the SUV for 18 F-FDG was significantly lower in endometrial hyperplasia than in carcinoma, a significant difference between high-risk and low-risk carcinoma was observed only in SUV for 18 F-FES. High-risk carcinoma showed a significantly greater 18 F-FDG-to-18 F-FES ratio (3.6 6 2.1) than did low-risk carcinoma (1.3 6 0.5, P , 0.01) and hyperplasia (0.3 6 0.1, P , 0.005). Low-risk carcinoma showed a significantly higher 18 F-FDG-to-18 F-FES ratio than hyperplasia (P , 0.0001). In ROC analysis, the most accurate diagnostic PET parameter for predicting high-risk and low-risk carcinoma was the 18 F-FDG-to-18 F-FES ratio. The optimal 18 F-FDG/ 18 F-FES cutoff value of 2.0, determined by ROC analysis, revealed 73% sensitivity, 100% specificity, and 86% accuracy, which was better than the 77% accuracy for MRI. The 18 F-FDGto-18 F-FES ratio of 0.5 yielded a correct diagnosis for carcinoma from hyperplasia with 100% accuracy. Conclusion: Endometrial carcinoma reduces estrogen dependency with accelerated glucose metabolism as it progresses to a higher stage or grade. 18 F-FES and 18 F-FDG PET studies provide a new index of the 18 F-FDG-to-18 F-FES ratio, which is considered the most informative index reflecting tumor aggressiveness. This index will be useful for making noninvasive diagnoses and deciding the appropriate therapeutic strategy for patients with endometrial carcinoma.