Objectives: This study sought to assess 18 F-fludarabine ( 18 F-FLUDA) PET/ CT's ability in differentiating primary central nervous system lymphomas (PCNSLs) from glioblastoma multiformes (GBMs). Patients and Methods: Patients harboring either PCNSL (n = 8) before any treatment, PCNSL treated using corticosteroids (PCNSLh; n = 10), or GBM (n = 13) were investigated with conventional MRI and PET/CT, using 11 C-MET and 18 F-FLUDA. The main parameters measured with each tracer were SUV T and T/N ratios for the first 30 minutes of 11 C-MET acquisition, as well as at 3 different times after 18 F-FLUDA injection. The early 18 F-FLUDA uptake within the first minute of injection was equally considered, whereas this parameter was combined with the later uptakes to obtain R FLUDA 2 and R FLUDA 3 ratios. Results: No significant differences in 11 C-MET uptakes were observed among PCNSL, PCNSLh, and GBM. With 18 F-FLUDA, a clear difference in dynamic GBM uptake was observed, which decreased over time after an early maximum, as compared with that of PCNSL, which steadily increased over time, PCNSLh exhibiting intermediate values. The most discriminative parameters consisting of R FLUDA 2 and R FLUDA 3 integrated the early tracer uptake (first 60 seconds), thereby provided 100% specificity and sensitivity. Conclusions: 18 F-FLUDA was shown to likely be a promising radiopharmaceutical for differentiating PCNSL from other malignancies, although a pretreatment with corticosteroids might compromise this differential diagnostic ability. The diagnostic role of 18 F-FLUDA should be further investigating, along with its potential of defining therapeutic strategies in patients with PCNSL, while assessing the treatments' effectiveness.

Background. Breast cancer is the second most common cancer worldwide. Despite significant advances in breast cancer treatment, more than 50 % of patients develop recurrence following completion of treatment. If there is a suspicion of disease progression, the differential diagnosis of metastatic tumor and non-metastatic lesion using the standard imaging methods can be difficult. A modern approach to the detection and assessment of the extension of recurrent disease is individual evaluation of the biological characteristics of the tumor, including determination of the status of estrogen receptors with the goal of adequate treatment. PET/CT with 18F-fluoroestradiol in patients with hormone-dependent breast cancer can be used to determine the expression of estrogen receptors (RE) in tumor tissue and assess the presence of receptor-positive metastases throughout the body in a single study. Case description. We report the cases of 55-year-old and 57-year-old women with hormone-dependent breast cancer after standard treatment (surgery, radiation therapy and hormone therapy). During hormone therapy, lung lesions were detected in both patients. To assess the activity of these lesions, 18F-fluoroestradiol PET/CT was used. In the first case, a low uptake of 18F-FDG was observed. In the other case, no18F-FDG uptake was found. Given that both patients had hormone-dependent breast cancer, it was decided to perform PET/CT with 18F-fluoroestradiol (18F-FES) to evaluate the expression of ER. In the first case, the 18F-FES uptake was detected in all lesions that indicated the evidence of metastases. Histological examination confirmed the evidence of metastatic tumor. In the second case, no uptake of 18FFES was detected in the foci and the patient was followed-up for 6 months. Computed tomography showed decrease in the size of lesions.Conclusion. The use of 18F-FES PET/CT can be an important diagnostic tool for detection of disease progression in patients with hormone-dependent breast cancer. In case of detection of positive foci on 18F-FES PET/CT scans, hormone therapy for breast cancer can be administered without invasive procedures for verifying the diagnosis.

No abstract

The study of plastic and energy metabolism and their correlation with various histologic types of brain gliomas. Assessment of heterogeneity tumor structure and adjacent brain tissues by comparing MRI and 11C-methionine and 18F-fluorodeoxyglucose PET/CT data. Materials and methods. 52 patients (M/F 27/25, average age 48±12 years) with gliomas were enrolled in this study: glioblastoma (n = 19), anaplastic astrocytoma (n=9), diffuse astrocytoma (n=9), anaplastic oligodendroglioma (n=6), oligodendroglioma (n=6). Research protocol consisted from MRI before (T2, T2-FLAIR, 3DT1 (FSPGR) and after contrast enhancement (2DT1 (SE)) and dynamic MET and FDG PET/CT.Quantification parameters were: tumor to normal index (T/N) at last 10 min of time-activity curve (reflects the activity of metabolic processes), T/N in first peak of maximum uptake (Pmax) during first 60sec of study (reflects delivery level of radiopharmaceutical agent). Measurements were made in three areas: 1 -tumor core, 2 -edema/infiltration, 3 -intact brain tissue in close vicinity to the tumor borders (outside the T2-FLAIR hyperintensity zone). Сomparison was made between areas 1 and 2, 2and 3, and with intact brain tissue reference; MET and FDG accumulation correlations were studied.Results. Significant differences in T/N MET between areas 1 and 2 were obtained in all gliomas (p <0.05). Pmax MET differed only in glioblastomas (p <0.0001) and oligodendrogliomas (p <0.05), which correlated with the high level of vascularization of these tumor types. T/N FDG significantly differed between area 2 and 3 (p <0.05), which might allow to evaluate the boundaries of infiltrative growth of glioma, with mandatory comparison with MRI. Strong stable correlations of plastic and energy metabolism (as well as high level of radiopharmaceutical agent delivery) in the core of astrocytomas (Grade II-III) (Rs 0.8, p <0.05) and edema/infiltration area around of glioblastomas (Rs 0.5, p = 0, 02) were found and proved the evolutionary theory of glioma growth. Conclusion.The patterns of MET/FDG distribution as well as plastic and energy metabolism correlations in different tumor areas (core and edema/infiltration) and intact brain tissue in close vicinity to the tumor borders bring us closer to understanding the fundamental metabolic processes of brain gliomas.

No abstract