Evaluation of the Accuracy of Standardized Uptake Values of 18F-fluorodeoxyglucose in Lung Lesions Based on Phantom Studies.

The aim of the study was to estimate the accuracy of standardized uptake values of 18F-fluorodeoxyglucose (18F-FDG) in lung lesions during positron emission tomography combined with computed tomography (PET/CT) imaging, based on phantom studies performed for different PET/CT scanners. MATERIALS AND METHODS: The analysis of the PET/CT with 18F-FDG data was performed for 86 patients newly diagnosed with the lung lesions: malignant tumors (n=37), benign tumors and inflammatory diseases (n=49). The criteria for inclusion in the study were developed considering the recommendations of the Fleischner Society (2017). The characteristics of the lesions on CT met the following requirements: a round shape or close to it; total size of 8 to 30 mm; solid or subsolid structure (with the exception of lesion with ground-glass opacity); a solid part size of ≥8 mm. All the patients had no signs of pleurisy, lymphadenopathy, or cancer history. PET/CT imaging with 18F-FDG was performed with three scanners: Discovery 690 (General Electric, USA), Biograph mCT 128 (Siemens, Germany), and Biograph mCT 40 (Siemens); the preparation of patients prior to the scan was standardized. To determine the reference accumulation of a radiopharmaceutical in the pathological lesion, four scans of a specialized NEMA IEC PET Body Phantom Set (USA) were performed for each scanner. For each unit, the recovery coefficients (RCs) of radioactivity, maximum and recovered (corrected) standardized uptake values (SUVs) were determined. Statistical relationship between the size of lesions, SUVmax and SUVcorrect was evaluated. Data processing was performed using MedCalc v. 19.2.0 software. RESULTS: During the phantom study, the underestimation of the radioactivity was determined in the spheres with the diameters of 10 and 13 mm, overestimation was observed in the sphere with the diameter of 28 mm. Both underestimation and overestimation of radioactivity were determined for the spheres with a diameter of 17 and 22 mm.SUVmax differed from the reference values for 85 patients (98.8%). The underestimation of these values was found for 63 patients (73.2%) due to the partial volume effect. The greatest underestimation was observed for the patients with 8 mm diameter lesions. Depending on the scanner, the underestimation of the SUVmax in these patients reached up to 54-73%. For 9 patients (25%) with malignant tumors of 9-12 mm, the utility of RC made it possible to avoid false negative results. For the lesions with a diameter of 30 mm, an overestimation of SUVmax up to 22% was determined due to the negative influence of the reconstruction algorithms. CONCLUSION: The use of RC eliminates the influence of the partial volume effect and reconstruction methods on the accuracy of estimating the SUVmax in lung lesions, which ensures reproducibility, increase in the information content of the method, as well as the comparability of the results of PET/CT with 18F-FDG obtained on the different models of PET/CT units with different technological characteristics.

[Comparative analysis of the informative value of 18F-fluorodeoxyglucose and 11C-methionine positron emission tomography in the differential diagnosis of solitary lung masses].

OBJECTIVE: To study the possibilities of enhancing the efficiency of differential diagnosis of solitary lung masses by optimizing the quantitative analysis of positron emission tomography (PET) data when two radiopharmaceuticals (RP) (18F-fluorodeoxyglucose (18F-FDG) and 11C-methionine) are used alone and in combination. MATERIAL AND METHODS: A comprehensive examination involving 18F-FDG and 11C-methionine PET was made in 116 patients with solitary lung masses of various genesis. A final diagnosis in the examinees was established from the results of postoperative material morphological analysis and/or laboratory tests and those of X-ray follow-up. RESULTS: No 18F-FDG and 11C-methionine hyperfixation was found in patients with benign tumors and in the majority of patients with focal pneumofibrosis. At 18F-FDG and 11C-methionine PET, RP accumulation was recorded in all patients with lung cancer (LC) and in patients with inflammatory diseases. Three patients with 18F-FDG PET-negative typical carcinoid tumors were noted to have increased 11C-methionine uptake. At 11C-methionine PET, RP accumulation was recorded in the projection of formation in all the patients with LC and in 38 of the 42 patients with inflammatory diseases. Regardless of the used RP, the Standardized Uptake Value (SUV) was significantly lower in the patients with inflammatory diseases than in those with LC (p ≤ 0.05). CONCLUSIONS: When RP is used alone, the diagnostic efficiency of C-methionine PET in the differential diagnosis of lung tumors and inflammations is higher than that of 18F-FDG PET. At the same time, the highest PET is seen when 18F-FDG and 11C-methionine are used in combination.

[First experience of using positron emission tomography with 11C-choline in prostate cancer (PC)].

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.

[Sensitivity of PET with 18F-fluorodesoxyglucose in the diagnosis of neuroendocrine tumors of the lungs].

PET with 18F-FDG was administered to 46 patients with different morphological types of neuroendocrine tumors. The method appeared to be highly sensitive in the diagnosis of atypical carcinoids as well as neuroendocrine large-cell lung cancer and small-cell lung cancer. At the same time its imaging capabilities in the detection of typical carcinoids were limited. The sensitivity of PET in these patients was 66.7%. However, the absence of 18F-FDG hyperfixation in typical carcinoids had strong evidence in favor of conditional benign process.

[Current possibilities of radiodiagnosis in liver tumors].

The report deals with potential of present-day techniques for radiological imaging, differential diagnosis and working out of modalities of treatment for primary and metastatic hepatic tumors. Results of complex examination (ultrasound, CT, MRI, PET using fluorine -18 FDG) of patients with benign and malignant tumors are discussed. Sensitivity and specificity of each procedure have been identified to be used in diagnosis of large-size tumors.

[Use of 18F-FDG PET scan in the diagnosis of large liver neoplasms and in the evaluation of therapeutic effectiveness].

The study involved 207 patients with large-size tumors. Results of 18FDG PET pointed to the basic factor of malignant transformation--foci of enhanced accumulation of radiological medicinal substances. Absence of ultrasound and CT-based evidence of such pathological accumulations contributed to interpretation of changes as benign ones. The effectiveness of chemotherapy was assessed by tumor metabolic response to treatment given at the time of 18FDG PET examination.

[Role of 18F-FDG PET scan in the differential diagnosis of large pancreatic masses].

Results of standard 18FDG PET and double-phase scanning were compared in the course of differential diagnosis of pancreatic cancer and chronic pseudotumorous pancreatitis, particularly, during exacerbation. PET diagnosis of cancer was confirmed in 6.5% while that of double-phase scanning--100%.

[Role of 18F-FDG PET in tumor grading and evaluating effectiveness of therapy in malignant lymphomas].

The report compares the results of (multi-layer spiral computed tomography) (MSCT), 67 Ga citrate lymph scintigraphy and 18FDG PET in patients with Hodgkin's disease. The predictive significance of the latter method exceeded that of MSCT and ultrasound in diagnosing lymph node neoplasia below the diaphragm. As far as peripheral and mediastinal lymph nodes are concerned, the MSCT efficiency of the three procedures was comparable. Advantage was offered by PET in early evaluation of therapeutic effectiveness. Moreover, its practical significance for assessing tumor sensitivity to therapy as well as differentiation between viable tumor tissue and fibrosis was demonstrated.

[Neoadjuvant intra-arterial oil chemoembolization and adjuvant selective intra-arterial chemoinfusion in the combined treatment of pancreatic cancer].

Neoadjuvant intra-arterial oil chemoembolization and adjuvant selective intra-arterial chemoinfusion with gemicitabine was administered to 28 patients with operable exocrine pancreatic cancer. It was well tolerated and not followed by complications which allowed for gastropancreatoduodenal resection to be carried out in all cases. Complete course of combined treatment was given to 23 out of 28 patients (82.1%). As a result, 2-, 3- and 5-year actuarial survival rates were 23.9, 17.4 and 13%, respectively. Long-term survival was recorded among patients without metastases into regional lymph nodes: two of them have survived without relapse for more than 5 years and one died of tumor progression after 4 years of the follow-up.

[Positron emission tomography with 18-fluorine deoxyglucose in the diagnosis and assessment of prostate cancer].

Results of PET studies using 18-fluorine deoxyglucose (18-FDG) in patients with large-size masses (51) are discussed. Histologically-confirmed prostate cancer was diagnosed in 36 (70.5%), benign hyperplasia--12 (23.5%) and chronic prostatitis--3(6%). 18FDG PET was conducted as whole body irradiation. Our results established its high predictive significance in identifying the scope of tumor involvement. However, the latter's potential is limited in diagnosis of primary tumor node due to low rate of glycolysis in it.

[Twelve years' clinical experience in using positron emission tomography: advances and prospects].

The paper describes 12 years' experience in using positron emission tomography (PET) at the Russian Research Center of Radiology and Surgical Technologies to detect cancer, cardiac, and psychoneurological diseases, to make their differential diagnosis, and to evaluate the efficiency of their treatment. It shows the capacities of PET using various radiopharmaceutical agents in a broad spectrum of the above abnormalities and defines prospects for further development of the technique.

[Clinical experience in using 18F-FDG PET in the staging and restaging of malignant lymphomas].

The present study was undertaken to determine the diagnostic accuracy of positron emission tomography (PET) in the staging and restaging of malignant lymphomas. For determination of the extent of a neoplastic process, complex radiation examination was conducted in 67 patients with malignant lymphomas. In 12 (17.9%) cases, the stage of the disease was changed, as evidenced by PET. There is evidence that the technique is of high diagnostic accuracy in detecting malignancies of l ymph nodes, skeletal system, and parenchymatous organs in lymphoproliferative diseases.

[Positron emission tomography in oncourology].

The authors present the results of the examination of 61 patients with genitourinary space-occupying lesions, using 18F- fluorodeoxyglucose positron emission tomography (PET) in whole body mode. In all cases the diagnosis was verified morphologically. The results demonstrated high diagnostic accuracy of PET, including possibility to determine the extent of oncourological cancer. However, the method displays poor efficacy in cases of hypernephroid cancer due to low level of glycolysis in this type of tumor.

[The role of positron emission tomography with C18-Fluorodeoxyglucose in clinical oncology]. / Primenenie pozitronnoi émissionnoi tomografii C18-F-ftordezokcilgliukozoi v klinicheskoi onkologii.

The study was concerned with evaluation of the diagnostic potential of positron emission tomography (PET) with 18-FDG in clinical oncology and elucidation of its role in assessing therapy effectiveness. The Ecat Exact 47 and Ecat Exat HR+ (Siemens) insatllations were used to examine 674 patients, with Whole Body protocol used in 585. PET with 18-FDG proved highly effective in diagnosing malignancies of the breast, lung, liver, pancreas, testis, brain and lymphoma as well as evaluating the efficacy of therapy.

[Assessment of 18FDG PET for diagnosis of pancreatic tumors]. / Vozmozhnosti PET s 18F-FDG dlia diagnostiki opukholei podzheludochnoi zhelezy.

The paper examines the informational value of positron emission tomography (PET) using 18FDG in the diagnosis of malignant of neoplasms of the pancreas and in the estimation of the extent of a metastatic involvement. Forty-four patients (26 males and 18 females whose age ranged from 28 to 60 years) with histologically verified cancer of the pancreas were examined. The study was conducted in the whole body mode on an Ecat Exact 47 positron emission tomograph following 70-90 minutes of administration of 18FDG, 370-420 MBk. To assess the findings, the differential accumulation ratio (DAR) of formation/liver was calculated. The mean DAR in patients with benign and malignant pancreatic tumors was 1.17 +/- 0.064 and 4.90 +/- 0.3 (p < 0.05). There was a false positive case in a patient with an exacerbation of chronic pancreatitis in the study. A relationship was observed between the level of tumor tissue 18FDG capture and the degree of malignancy. PET scanning in the whole body mode estimates the extent of a tumorous process. The authors' data show that the liver was most commonly involved in a metastatic process (96.6%). Hence, 18FDG PET is a highly informative technique in the diagnosis of malignant pancreatic tumors and in the estimation of the extent of a metastatic process and permits a differential diagnosis between benign and malignant tumors.