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Brachytherapy with implantation of micro sources based on isotope 125I is a preferred treatment for localized prostate cancer without signs of germination of the gland capsule and in the absence of signs of metastases (stage cT1-T23aN0M0). Structural imaging methods (ultrasound, computed tomography, and magnetic resonance imaging) do not have high specificity in the differential diagnosis of prostate cancer. Hybrid technologies of radiation imaging (single-photon emission computed tomography/computed tomography, positron emission tomography/computed tomography, and positron emission tomography/magnetic resonance imaging) combine the advantages of high sensitivity of cross-sectional structural imaging methods (computed tomography and magnetic resonance imaging) and high specificity of molecular imaging methods (single-photon emission computed tomography and positron emission tomography) with tumorotropic radiopharmaceuticals. In this original clinical study, based on seven observations of localized prostate cancer (Gleason 6–7), it was shown that the precision of low-dose brachytherapy using 125I micro sources of localized prostate carcinomas, along with targeted biopsy, can be increased using hybrid methods of PSMA-receptor molecular imaging (single-photon emission computed tomography/ computed tomography, positron emission tomography/ computed tomography). The single-photon emission computed tomography/ computed tomography method is more accessible than positron emission tomography/ computed tomography. Moreover, when coupled with cold kits (HYNIC-PSMA), it allows research within any radioisotope diagnostics laboratory equipped with single-photon emission computed tomography/ computed tomography. The innovative technology of PSMA-navigation biopsy and brachytherapy, under the control of hybrid molecular imaging, can be used in primary and recurrent cases of localized prostate cancer, increases the accuracy and reduces the traumatic nature of procedures, and increases the medical and economic efficiency of low-dose brachytherapy with 125I micro sources. Further research is needed to improve the technology and evaluate its long-term results.

Objective: In this study, we aimed to determine the independent predictive parameters of overall survival (OS) ofpatients with inoperable pancreatic ductal adenocarcinoma (PDAC) and to investigate whether these parameterscan be used as potential biomarkers to shape precision medicine practices for PDAC patients.Material and Methods: The clinical and pathological data of patients who were diagnosed with inoperablepancreatic ductal adenocarcinoma between January 2016 and December 2019 and who underwent18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in our departmentwere retrospectively analyzed. Tumor diameter, maximum standardized uptake value (SUVmax), metabolictumor volume (MTV), and total lesion glycolysis (TLG) were calculated from FDG PET/CT images. Univariate andmultivariate Cox regression analyzes were performed to investigate the variable affecting overall survival. Overallsurvival data were analyzed using the Kaplan–Meier method, using the log-rank test.Results: A total of 48 patients, 31 male and 17 female, with a mean age of 65.85 ± 1.64 were included in the study.In univariate Cox regression analyzes were performed to examine the factor affecting OS. Clinicopathologicalfactors (tumor localization, tumor diameter, stage) and FDG PET/CT parameters (SUVmax, MTV and TLG) with ap-value of < 0.2 were compared to multivariate Cox regression analysis. TLG was found to be the only independentpredictor of OS. In the Kaplan-Meier analysis, the median OS duration of the patients with a median value of TLGbelow 298.34 was 13.87 months, while the median OS duration was found to be 4.97 months in patients with a TLGvalue above this value.Conclusion: In our study, TLG value, which is an FDG PET/CT parameter that reflects both the metabolic activity andthe volume of the tumor, was found to be the only independent predictor of the OS of inoperable PDAC patients.TLG can be used as a potential biomarker for survival in patients with inoperable PDAC and may assist precisionmedicine applications.

Objectives: To compare block sequential regularized expectation maximization (BSREM) and ordered subset expectation maximization (OSEM) for the detection of in-transit metastasis (ITM) of malignant melanoma in digital [18F]FDG PET/CT. Methods: We retrospectively analyzed a cohort of 100 [18F]FDG PET/CT scans of melanoma patients with ITM, performed between May 2017 and January 2020. PET images were reconstructed with both OSEM and BSREM algorithms. SUVmax, target-to-background ratio (TBR), and metabolic tumor volume (MTV) were recorded for each ITM. Differences in PET parameters were analyzed with the Wilcoxon signed-rank test. Differences in image quality for different reconstructions were tested using the Man-Whitney U test. Results: BSREM reconstruction led to the detection of 287 ITM (39% more than OSEM). PET parameters of ITM were significantly different between BSREM and OSEM reconstructions (p < 0.001). SUVmax and TBR were higher (76.5% and 77.7%, respectively) and MTV lower (49.5%) on BSREM. ITM missed with OSEM had significantly lower SUVmax (mean 2.03 vs. 3.84) and TBR (mean 1.18 vs. 2.22) and higher MTV (mean 2.92 vs. 1.01) on OSEM compared to BSREM (all p < 0.001). Conclusions: BSREM detects significantly more ITM than OSEM, owing to higher SUVmax, higher TBR, and less blurring. BSREM is particularly helpful in small and less avid lesions, which are more often missed with OSEM. Key Points: • In melanoma patients, [18F]FDG PET/CT helps to detect in-transit metastases (ITM), and their detection is improved by using BSREM instead of OSEM reconstruction. • BSREM is particularly useful in small lesions. [ABSTRACT FROM AUTHOR]

Uveal melanoma is the most common intraocular malignancy. Despite significant progress in the treatment of the primary tumor, uveal melanoma continues to be the most aggressive tumor due to its high potential for hematogenous metastatic spread. Uveal melanoma metastases are located mostly in the liver. Overall survival of patients with liver metastases is 4 to 15 months. There is no adjuvant systemic therapy to prevent metastases of uveal melanoma. In this paper, we aim to analyze achievement in diagnosis of metastatic uveal melanoma made during the last 10 years and to show advantages and disadvantages of the main diagnostic methods. The last years showed the emergence of understanding the differences between skin and uveal melanoma based on different molecular genetic abnormalities and different signaling pathways of these tumors. The success of target treatments for skin melanoma is not applicable to uveal melanoma. Skin and uveal melanoma responds differently to immune checkpoint inhibitors. Insufficient efficacy of systemic chemotherapy, immune and target therapy has made it necessary to develop techniques of local chemoembolization and radioembolization of uveal melanoma metastases. At present, there are no available assessment algorithms for the management of patients with uveal melanoma and suspected metastases. Ultrasonography, if seen as available techniques for radiology diagnostics, should be enhanced either by the intravenous contrast, or by qualifying computed tomography. The use of positron emission tomography / computed tomography has not demonstrated the maximal diagnostic value in identification of liver metastases, and, taken into account its high costs, low availability, and large radiation dose, it cannot be considered as a feasible method for every 6 months' application. The most effective diagnostic method is magnetic resonance imaging with the liver-specific contrast agents, due to the possibility to detect metastases of less than 1 cm in diameter. However, this technique has not been widely accepted clinically due to high costs, contraindications and a big proportion of false positive results. Current armamentarium of radiation techniques that could be potentially applicable for visualization of hepatic focal abnormalities is rather impressive and is being continuously updated; however, the problem of the metastatic uveal melanoma diagnosis remains unsolved.

Purpose: To investigate the physiological uptake of hybrid fluorine-18-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) before and after an uncomplicated endovascular aneurysm sealing (EVAS) procedure as a possible tool to diagnose EVAS graft infection and differentiate from postimplantation syndrome. Materials and Methods: Eight consecutive male patients (median age 78 years) scheduled for elective EVAS were included in the prospective study (ClinicalTrials.gov identifier NCT02349100). FDG-PET/CT scans were performed in all patients before the procedure and 6 weeks after EVAS. The abdominal aorta was analyzed in 4 regions: suprarenal, infrarenal neck, aneurysm sac, and iliac. The following parameters were obtained for each region: standard uptake value (SUV), tissue to background ratio (TBR), and visual examination of FDG uptake to ascertain its distribution. Demographic data were obtained from medical files and scored based on reporting standards. Results: Visual examination showed no difference between pre- and postprocedure FDG uptake, which was homogenous. In the suprarenal region no significant pre- and postprocedure differences were observed for the SUV and TBR parameters. The infrarenal neck region showed a significant decrease in the SUV and no significant decrease in the TBR. The aneurysm sac and iliac regions both showed a significant decrease in SUV and TBR between the pre- and postprocedure scans. Conclusion: Physiological FDG uptake after EVAS was stable or decreased with regard to the preprocedure measurements. Future research is needed to assess the applicability and cutoff values of FDG-PET/CT scanning to detect endograft infection after EVAS. [ABSTRACT FROM AUTHOR]

Background - Cutaneous malignant melanoma (CMM) is one of the most lethal malignancies and the follow-up involves, in addition to clinical examination and analysis of tumor markers, several imaging methods such as the Positron Emission Tomo- graphy/Computed Tomography (PET/CT) exam with 18fluor-fluorodeoxyglucose (18F-FDG). The aim of the study is to evaluate the utility of PET/CT in the assessment of the extension of the disease and of suspected recurrence in the CMM, comparing the imaging findings with those described in CT studies. Methods - It was performed a retrospective analysis of 62 PET/CT studies in 50 patients diagnosed with CMM. It was excluded a study which had a doubtful outcome (pulmonary nodule) and it was not possible to perform its diagnosis. The information related to the results of pathologic studies and imaging studies was obtained through medical history and medical reports of CT and PET/CT. A database was created with the collected data through Excel software and a descriptive statistical analysis was carried out. Results - Of the PET/CT studies analyzed, 31 were considered true positives (TP), 28 true negatives (TN), 1 false negative (FN) and 1 false positive (FP). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of PET/CT for staging and evaluation of suspicious relapse in CMM are, respectively, 96.9%, 96.6%, 96.9%, 96.6% and 96.7%. From the CT results considered in statistical analysis, 14 corresponded to TP, 12 to TN, 3 to FP and 5 to FN. The sensitivity, specificity, PPV and NPV, and accuracy of CT for staging and evaluation of suspicious relapse in CMM are, respectively, 73.7%, 80.0%, 82.4%, 70.6% and 76.5%. Comparatively to the CT results, PET/CT allowed a change in therapeutic approach in 23% of studies. Conclusion - PET/CT is a useful tool in evaluating CMM, characterized by high diagnostic accuracy in staging and in the evaluation of suspected recurrence of MMC compared to CT only. [ABSTRACT FROM AUTHOR]

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We report a case of acute Epstein–Barr virus (EBV) infection in which the clinical syndrome and pattern of F-18-2-fluoro-2-deoxy-d-glucose (FDG) uptake mimicked malignant lymphoma. A 53-yr-old man presented with 2 wk of high fevers, night sweats, sinus congestion and severe fatigue. The patient was treated for 1 wk with broad-spectrum antibiotics for acute sinusitis without any improvement. Persistence of fevers and presence of abnormal lymphadenopathy seen on the abdominal computed tomography (CT) were concerning lymphoma with B symptoms. FDG positron emission tomography (PET) showed avid FDG uptake in numerous abdominal/pelvic nodes, liver, spleen and bone marrow. These findings were highly suspicious for lymphoma. Patient underwent a pelvic lymph node biopsy which showed large granular lymphocytes that were predominantly T cells. Bone marrow biopsy showed diffuse infiltration with plasmocytoid cells that were not kappa lambda restricted. Additional diagnostic workup became available showing positive EBV IgM titers and negative IgG levels indicating acute infectious mononucleosis. Lymph node biopsy stained positively with EBV-encoded RNA. We concluded that patient’s abnormal FDG PET was most likely secondary to acute EBV infection. After 2 months, follow-up FDG PET/CT showed marked improvement in lymphadenopathy and decreased hypermetabolic activity in the liver and spleen. Other than EBV, there are many other FDG-avid non-malignant conditions that may lead to false-positive PET scans. FDG accumulates in inflamed and infected lesions with increased glucose metabolism. This case underscores the importance of maintaining a broad differential and restricting use of PET scans for staging. [ABSTRACT FROM AUTHOR]