In June 2019, a drone image recording was performed equipped with an RGB camera on an experimental wheat field at an interval of seven days three times a day. Within one day (12.06.2019) information was collected about the weather conditions and eight measurements were made every hour. The commonly accepted indices were calculated: VARIgreen and ExG for the one-month and one-day observations of the received RGB digitized information. A regression model was created for a full factor experiment of type 23. The interaction of the factors that characterize the conditions of the video was evaluated. Conclusions were formulated as to the influence of the factors under which the observations were made. A recommendation was made with regard to which part of the day it is most appropriate to take photos and video surveillance of wheat.
INTRODUCTION: According to the literature, 68Ga-FAPI-04 has receptor specificity for malignant neoplasms with overexpression of the fibroblast activation protein and is used to visualize various types of neoplasms, in particular head and neck cancer, gastrointestinal tract, lung, breast cancer with a high contrast ratio of the tumor to the background, and may possibly become an alternative to 18F-FDG.OBJECTIVE: The results of the first experience of using PET/CT with 68Ga-FAPI-04 in Russia.MATERIALS AND METHODS: A comparative analysis of the results of 68Ga-FAPI-04 and 18F-FDG PET/CTs with an interval of 1–3 days was carried out in 13 patients (four women and nine men) with various oncological diseases, examined from February to December 2021 in Granov Russian Research Center of Radiology and Surgical Technologies.RESULTS: In all 13 patients, it was possible to identify both primary tumors and their metastases with different tracer uptake. 68Ga-FAPI PET/CT compared with 18F-FDG PET/CT revealed more metastatic foci (135 vs 127) predominantly in the liver, peritoneum, mesentery, omentum, and brain due to low background uptake in these organs. In our observation, foci of increased 68Ga-FAPI-04 uptake localized in non-enlarged retroperitoneal lymph nodes in two patients. Also, in two patients with bone metastases from bladder cancer and stomach cancer, one false positive and one false negative result was obtained with 68Ga-FAPI-04.DISCUSSION: The high uptake of 68Ga-FAPI-04 in the tumor makes it a promising tracer for many types of cancer, especially in cases, where conventional 18F-FDG PET/CT faces limitations due to its pharmacokinetics. At the same time, PET/CT with 68Ga-FAPI-04, aimed at visualizing the tumor microenvironment, may have a higher sensitivity in detecting small lesions due to the predominance of stroma in them. 68Ga-FAPI showed better results in detecting both lytic and osteoblastic bone metastases compared to 18F-FDG.CONCLUSION: 68Ga-FAPI is a promising tracer for molecular imaging of most malignant neoplasms and requires further study. 68Ga-FAPI-04 can become an addition or a full-fledged solution when other tracers have limitations.
Introduction: Metabolic Tumor Volume (MTV) and Total Tumor Lesion Glycolysis (TLG) are used in 18F-fluorodeoxyglucose Positron-Emission Tomography combined with Computed Tomography (18F-FDG PET/CT) as functional markers, indicating tracer uptake in whole tumor. MTV and TLG are not yet engaged in clinical practice, because volume measurement accuracy depends on the selected measurement method, and optimal MTV and TLG segmentation is not established.Purpose: Assessment of accuracy of metabolic tumor volume measurement ways, using 18F-FDG PET/CT in patients with Diffuse Large B-Cell Lymphoma (DLBCL).Material and methods: Baseline 18F-FDG PET/CT performed in 21 patients with DLBCL. Tumor Volume (TV), measured on contrast enhanced CT (CTTV), considered as reference. While measuring MTV, we aimed to achieve a 1:1 ratio between CTTV and MTV. If anatomical and metabolic tumor contours matched, MTV was considered true (MTVtrue). Overall MTV and TLG measurements are 254. Tumor contouring, using relative thresholds, was made around Standardized Uptake Value (SUVmax) of tracer in tumor and intact liver.Results: On CT, the size of the lesions varied from 24 to 241 mm, M = 103.4±62.3, Me = 93 (48.5–155.5). In 15 (71.4 %) foci, hypodense areas of necrosis were determined. PET imaging revealed high tracer uptake in all foci of varying degrees of intensity. SUVmax values in tumors ranged from 5.8 to 30.5, Me = 20.4 (17.3–23.2). No significant correlation was found between the size of the foci and SUVmax (ρ = 0.17, p = 0.4744). The best accuracy in measuring MTV was observed when several thresholds were applied: VOIPERCIST, VOI2.5, VOIauto-contour, as well as VOI10 %, VOI15 % and VOI20 %. The optimal absolute threshold values were SUV values in the range from 2 to 3, and relative values in the range from 10 % to 20 % of the SUVmax in the tumor. MTV underestimation was more often determined using relative cut-off indices in the range of25–50 % and SUV thresholds ≥ 5.3.Conclusion: The results obtained showed that the use of a single threshold value for MTV segmentation in patients with DLBCL is not advisable. The choice of the MTV measurement method should be carried out individually for each lesion, taking into account its shape, size and structure, as well as the intensity and uniformity of tracer uptake in the tumor and adjacent anatomical structures.
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