Introduction. The minimum size of malignant brain tumors detected by positron emission and computed tomography (PET-CT) exceeds 6-7 mm. One of the ways to increase the sensitivity of PET-CT in detecting of malignant brain tumors is to increase the administered activity of the radiopharmaceutical 11C-choline.Purpose & tasks. The aim of the study was to experimentally study the possibility of obtaining a small-size glioblastoma (GB) images (up to 4 mm) by PET-CT with the 11C-choline.Materials and methods. The study was performed on 24 rats with implanted intracerebral tumor «Glioma C6» (glioblastoma). Animals underwent magnetic resonance imaging (MRI) with contrast enhancement (CE) and PET-CT with 11C-choline for 21 days after tumor transplantation.Results. It was shown that using two methods: MRI with CE and PET-CT with 11C-choline, a glioblastoma up to 4 mm can be convincingly visualized.Conclusion. The data obtained can be crucial for early detection of glioblastoma, justification of treatment tactics, evaluation of the treatment effectiveness and prediction the outcome of the disease.

The review presents an analysis of the literature on the diagnosis of gliomas and the study of their structural and biological features based on implementation of new techniques in clinical practice of diagnostic imaging. These techniques include perfusion technologies for multislice spiral computed tomography (MSCT), magnetic resonance imaging (MRI), functional MRI, proton magnetic resonance spectroscopy (MRS), single photon emission computed tomography (SPECT), and positron emission tomography (PET) with various radiopharmaceuticals (RPHs), first and foremost, labeled amino acids, such as11C-L-methionine and18F-Fluoroethyltyrosine. There is presented that with the application of these two methods (MRI and PET), the most important biochemical processes underlying oncogenesis of malignant tumors might be studied by non-invasive way. The obtained data can be crucial for an early detection of tumor lesions, staging the pathological process, rationale for therapeutic tactics, personalization of treatment, evaluation of the efficiency of therapy at early stages and prognosis of the disease result.

The review presents an analysis of the literature on the diagnosis of brain tumors and the study of their structural and biological features based on application of nuclear imaging: single photon emission computed tomography (SPECT) and positron emission tomography (PET) with different radiopharmaceuticals (RPHs), especially amino acids (11C-L-methionine and 18F-FET). It is shown PET-CT and SPECT allow to noninvasively study the most important biochemical processes underlying the oncogenesis. The obtained data can be crucial for an early detection of tumor lesion, staging the pathological process, personalization of treatment, evaluation of the efficiency of therapy and prognosis of the oncologic disease outcome.

The paper presents a 82 Sr/ 82 Rb-generator and shows the possibility and perspectives to use the radiopharmaceutical (RFP) «Rubidium chloride, from 82Rb generator» (hereinafter referred to as « 82 Rb-chloride») for the diagnosis of brain tumors (GM) based on the experience of the use of the radiopharmaceutical in the FGBI «RRCRST» of the Ministry of Healthcare of Russia. Results of observation of 23 patients are presented with malignant and benign tumors, and non-neoplastic lesions in the brain. The tendency was detected for the prevalence of increased accumulation of 82 Rb-chloride in malignant tumors as compared to benign tumors and in arteriovenous malformations (AVM) in which the 82Rb-chloride is accumulated within the vascular phase, but it is not retained. Ultra-short half-life of the radionuclide [ 82 Rb] (76 sec) and low radiation exposure arising when the 82Rb-chloride is intravenously injected, create completely new possibility for sequential use of two or more radiopharmaceuticals at examining a patient. For example, PET imaging with 18 F-FDG, 11 C-L-methionine or 11 C-choline can be performed in 7 minutes after the injection of the 82Rb-chloride to a patient. The efficiency of using 82 Rb-chloride as a diagnostic tool in the neurooncological patients is stated. The method was develop for dosing and injection of the radiopharmaceutical from a generator. Using a single generator of Rubidium-82 it is possible to run about 800 PET studies. Generator is reliable and easy in use.

The paper presents a 82 Sr/ 82 Rb-generator and shows the possibility and perspectives to use the radiopharmaceutical (RFP) «Rubidium chloride, from 82Rb generator» (hereinafter referred to as « 82 Rb-chloride») for the diagnosis of brain tumors (GM) based on the experience of the use of the radiopharmaceutical in the FGBI «RRCRST» of the Ministry of Healthcare of Russia. Results of observation of 23 patients are presented with malignant and benign tumors, and non-neoplastic lesions in the brain. The tendency was detected for the prevalence of increased accumulation of 82 Rb-chloride in malignant tumors as compared to benign tumors and in arteriovenous malformations (AVM) in which the 82Rb-chloride is accumulated within the vascular phase, but it is not retained. Ultra-short half-life of the radionuclide [ 82 Rb] (76 sec) and low radiation exposure arising when the 82Rb-chloride is intravenously injected, create completely new possibility for sequential use of two or more radiopharmaceuticals at examining a patient. For example, PET imaging with 18 F-FDG, 11 C-L-methionine or 11 C-choline can be performed in 7 minutes after the injection of the 82Rb-chloride to a patient. The efficiency of using 82 Rb-chloride as a diagnostic tool in the neurooncological patients is stated. The method was develop for dosing and injection of the radiopharmaceutical from a generator. Using a single generator of Rubidium-82 it is possible to run about 800 PET studies. Generator is reliable and easy in use.

The paper presents a case of a 52-year-old female patient with pleomorphic malignant fibrous histiocytoma/ undifferentiated pleomorphic sarcoma of the left atrium. One year after surgical resection of the primary tumor, microsurgical removal of the right parietal lobe metastatic tumor was performed. PET/CT with 11C-methionine and 18F-FDG performed 2 months after surgical resection of brain metastasis revealed local recurrence of sarcoma in the left atrium and left lateral ventricle metastases. This clinical case demonstrates high diagnostic accuracy of PET/CT with 18F-FDG and 11C-methionine in detecting local recurrence of cardiac undifferentiated sarcoma, however, PET/CT with 11C-methionine appears to be superior to PET/CT with18F-FDG in detecting brain metastasis.

The aim of the investigation was to estimate the sensitivity of combined positron emission and computed tomography (PET/CT) in the diagnostics, extension and treatment efficiency of neuroendocrine tumors (NET) using Ga-68-DOTA-TATE as an imaging agent.Materials and Methods. PET/CT with Ga-68-DOTA-TATE was performed in 86 patients with pulmonary and gastrointestinal NET (55 patients underwent it preoperatively, 31 patients - postoperatively). All patients before PET/CT were administered a diagnostic dose of radiopharmaceutical (RP) at the rate of 1.5 MBq per a kilogram of body mass but not less than 100 MBq. The developed RP synthesis module (Gerat13-Ga-68) enabled to prepare a ready for intravenous administration Ga-68-DOTA-TATE within 15 min. Moreover, RP was defined to have a stably high radiochemical yield (over 50% without decay correction) and the appropriate quality. The patients were scanned 50-60 min after RP injection, the procedure being carried out according to a whole body protocol using PET/CT Discovery 690 (General Electric, USA). The data processing included the image analysis of computed and positron emission tomograms, as well as combined images. The main feature of sst-positive tissue tumor was pathological focal Ga-68-DOTA-TATE hyperfixation even if there were no evident structural changes of the organ according to CT findings. In cases when CT showed a tumor but the tumor didn't accumulated RP, its nature was considered to be malignant and the tumor was estimated as sst-negative.Results. In patients examined before treatment, the sensitivity of PET/CT with Ga-68-DOTA-TATE to diagnose a primary tumor was 90.9% (50/55). In 3 patients PET showed a sst-negative tumor, in 2 patients a primary mass was not detected after tomography either. In addition, an initially determined stage of the disease was confirmed by PET/CT in 36 of 47 cases (76.6%). The rest patients were found to have second metastases in different organs and systems.PET/CT findings in 13 of 31 patients examined after the treatment didn't coincide with those obtained by other techniques. In 6 patients the presence of pathological PR accumulation indicated no positive effect of the therapy, 3 patients were found to have secondary changes, 3 patients were detected to have a significant increase of liver metastases (only in CT), and 1 female patient after surgery appeared to have the disease recurrence in the stump of the left main bronchus.

Proper and accurate staging of the disease helps in the selection of treatment strategy and planning for further prognosis of cancer in patients with Hodgkin’s lymphoma (HL). Aim of the study was to examine the role of positron emission tomography (PET) with 18F-FDG in the staging of patients with HL, a comparison of PET findings with the results of computed tomography (CT) and evaluation of the prognostic value of interim PET performed after 2–3 cycles chemotherapeutic treatment in patients with HL. Eighty nine patients who presented with newly diagnosed HL underwent conventional staging methods including CT as well as PET with 18F-FDG. The sensitivity, specificity and diagnostic accuracy of PET in examination of pathological lymph nodes, extranodal organs and pathological process above and below the diaphragm were higher than that of CT. Significant decrease in the sensitivity of CT was revealed in the detection of the disease below the level of the diaphragm (68,5 %). In accordance with the PET results were changed stage and treatment in 10 (11,2 %) patients. After two or three cycles of chemotherapy, 66 patients had negative FDG-PET scans and 23 patients had positive scans. Three PET-negative patients relapsed. In the PETpositive group, nine patients progressed. In 14 (60,9 %) patients continued treatment resulted in complete remission. Survival analyses showed highly significant associations between early interim FDG-PET and progression free survival (p < 0,0001).

OBJECTIVE: To investigate the diagnostic value of 18F-FDG positron emission tomography (PET) in the diagnosis and staging of marginal zone non-Hodgkin lymphomas (NHLs). MATERIAL AND METHODS: Twenty-four patients with new-onset NHLs were examined. Extranodal MALT lymphoma, splenic marginal zone lymphoma (MZL), and nodal MZL lymphoma were diagnosed in 18, 3, and 3 patients, respectively. 18F-FDG PET was carried out by the standard protocol via whole-body examination, by estimating the standardized tracer uptake value (SUV(max)) in the abnormal foci. RESULTS: Most (83.3%) of the examinees were found to have abnormal tracer hyperfixation foci. The mean SUV(max) was 5.05 ± 0.9. There was no correlation between SUV(max) in the tumor foci and their metabolic sizes (r = 0.1; p = 0.7). No significant differences between the mean SUV(max) were found in patients with different histological types of MZL (p > 0.05). Disease staging by PET and other diagnostic methods yielded contradictory results in three patients. The final analysis suggested that the stage had been correctly determined in all the 3 patients from PET findings. CONCLUSION: The results of 18F-FDG PET suggest that it is of high iagnostic value in imag-ng marginal zone NHLs. The major advantage of PET is that it can accu-ately stage the disease, which can provide a ra-ionale for optimal treat-ent policy.

Characteristics of the developed 82 Rb medical generator intended for the production of Rubidium Chloride, 82 Rb from Generator radiopharmaceutical for positron emission tomography (PET) are examined. The results of laboratory tests and clinical trials are presented. The influence of thermal sterilization on the ionexchange characteristics of the sorbent based on hydrous tin(IV) oxide is studied. The possibility of radiation “self-sterilization” of the generator column and of the maintenance of aseptic conditions in it throughout the generator operation life is assessed. In the course of operation of one generator, it is possible to obtain up to 19 L of a sterile and apyrogenic solution of the radiopharmaceutical with permissible content of radioactive and stable impurities. The efficiency of the 82 Rb elution from the sorbent at different eluent flow rates is determined. The efficiency of using the generator in PET investigations in cardiology and oncology is demonstrated.

OBJECTIVE:To comparatively study the diagnostic capabilities of positron emission tomography (PET) with various tumorotropic radiopharmaceuticals (TRPs) in detecting malignant brain gliomas (BG) and estimating their degree.MATERIAL AND METHODS:One hundred and fourteen patients, including 47 with histologically verified glioblastoma multiforme (GBM), 27 with anaplastic astrocytoma (AA), 23 with benign astrocytoma (BA), and 17 with postoperative cysts, were examined. PET was performed using TRPs: 18F-fluorodesoxyglucose (18F-FDG), 11C-sodium butyrate (11C-SB), 11C-L-methionine (11C-MET), and 11C-choline (11C-COL).RESULTS:Malignant gliomas (GBM and AA) were clearly visualized by PET using 11C-MET, 11C-CHOL, and 11C-SB. 18F-FDG PET visualization of tumors was difficult because of increased RP accumulation in the cerebral cortex. WHO grades II-III gliomas were completely visualized by 11C-MET PET. Only some tumors were clearly displayed by PET with 11C-CHOL and 11C-SB. The accumulation indices (AI) obtained by 11C-CHOL PET in patients with malignant gliomas were, on average, 4.0- and 5.5-fold higher than those by 11C-MET and 11C-SB PET, respectively. Significant differences (p < 0.001) in AI obtained by "C-CHOL ("C-CHOL-AI) PET were first established between the patients with GBM (WHO grade IV) and those with AA (WHO grade III).CONCLUSION:11C-CHOL PET is the most sensitive method to identify gliomas and estimate their grade. The advantage of 11C-MET PET is the possible imaging of the entire volume of viable tumor tissue.

Purpose. The aim was to investigate the role of positron-emission and computed tomography (PET/CT) with 18 F-FDG in the diagnosis and staging of patients with indolent non-Hodgkin’s lymphoma, to compare PET/CT findings with the results of computed tomography (CT) and proliferative activity of tumor cells. Material and methods. 49 consecutive patients with untreated indolent non-Hodgkin’s lymphoma were evaluated in our study. Conventional staging methods including CT as well as PET/CT with 18 F-FDG were performed for investigating lymph node and extranodal manifestation of the disease. Results. The sensitivities, specificities and diagnostic accuracies in diagnosis for lymphomatous involvement of nodal regions were 75.7%, 98.4% and 86.8% for PET/CT and 51%, 98.4% and 74.4% for CT The accuracy in detecting extranodal manifestation for PET/CT was 84.6% compared to 71.8% for CT. Disease staging by PET/CT and conventional diagnostic methods was identical in 75.5% of patients, 24.5% showed discordant results. PET/CT correctly resulted in a higher stage than CT in more than 18% (n = 9) of the patients. No significant difference was found between the SUV max of the various types of indolent lymphoma (p = 0,065). The correlation of SUV max and Ki-67 index was not statistically significant (r = 0,1, p = 0,7). Conclusion. PET/cT provides significantly more accurate information compared to CT for diagnosis and staging of patients with indolent non-Hodgkin’s lymphoma.

OBJECTIVE: To define the role of 18F-FDG positron emission tomography (PET) performed after 2-3 chemotherapy cycles in the prediction of disease prognosis and to identify a group of patients requiring more intensive treatment. MATERIAL AND METHODS: Seventy-one patients with non-Hodgkin lymphoma of different histological types were examined. PET was carried out at different stages of diagnosis and primary treatment in the patients. RESULTS: The examinations made after 2-3 polychemotherapy (PCT) cycles indicated that 36 (50.7%) patients continued to have signs of metabolic activity of lymphoproliferative disease (a PET-positive group) and 35 (49.3%) patients were found to have no abnormal tracer accumulation foci (a PET-negative group). Twenty-nine (82.9%) patients from the PET-negative group continued to remain in complete remission throughout the follow-up (the median follow-up was 405 days). At late stages, 6 (17.1%) patients were identified to have abnormal tracer hyperfixation foci that were indicative of disease recurrence. Only 8 patients from the PET-positive group were observed to show a complete metabolic response to treatment at the end of first-line PCT. The metabolic activity of the disease was maintained in the remaining patients. The results of PET conducted at the late stages of the follow-up indicated that metabolically active tumor foci continued to be visualized in 20 (55.6%) patients and further treatment resulted in complete remission in 16 (44.4%) patients. CONCLUSION: PET findings could predict the further course of the disease and differentiate more intensive treatment-requiring patients at the early stages of chemotherapy.

Introduction into clinical practice of combined positron emission technology and computer tomography (PET/CT) allows in one study to identify structural and functional abnormalities. The study involves 32 patients who underwent PET/CT with "C-choline, including 5 patients with prostate cancer (PC), 3--with chronic prostatitis and 24--with biochemical PC recurrence. PET/CT with 11C-choline has a high diagnostic efficacy in detection of local recurrence and PC metastases in patients with biochemical PC recurrence. The results of visual analysis do not permit to distinguish PC from benign prostate diseases.