sequent shale swelling. In this study, we utilized Carboxymethyl Trimethyl Ammonium Chloride (CTAC) to inhibit shale swelling, representing a novel application for this particular cationic surfactant. Several experiments were carried out to assess the effectiveness of CTAC in preventing shale swelling and to gain insights into the underlying mechanisms. Moreover, based on the results, CTAC is highly effective at low concentrations and can be used with other common additives. Furthermore, the contact angle in the presence of CTAC, cetyltrimethylammonium bromide (CTAB), and potassium chloride (KCl) at 1 wt.% in the bentonite mixture was 77°, 75°, and 38°, respectively. Also, by adding CTAB, total shale recoveries in simple and complete drilling muds increased by 5.53% and 0.94%, respectively. Meanwhile, In the presence of CTAC, the increase was equal to 12.37% and 6.43%, respectively. In addition, CTAC and CTAB in the complete drilling mud reduced the swelling by 9.94% and 4.2%, respectively. Ultimately, comparative studies show that CTAC performs better as a new inhibitor than CTAB and KCl as conventional inhibitors.

This study presents an innovative approach to eliminating the pharmaceutical pollutant diclofenac sodium (DFS) by combining nanofiltration membrane technology with an electrochemical oxidation process. The nanofiltration membrane was prepared by phase inversion, and modified with cetyltrimethylammonium chloride (CTAC) to improve surface properties and pore structure. The concentrate from the nanofiltration treatment has been utilized as the input feed for the electrochemical section, employing Ti/SnO2-α-Fe2O3 electrodes. The PES/CTAC membrane exhibits a more uniform and stable pore structure, leading to increased permeability and antifouling properties. Additionally, the inclusion of CTAC through the surface adsorption mechanism improved the DFS rejection performance, achieving a maximum rejection rate of 65.2% for the membrane with a composition of 0.1 wt% CTAC. The obtained results show that the titanium electrode coated with SnO2 and α-Fe2O3 nanoparticles removed the DFS pollutant by 56%. In total, both membrane and electrochemical process removed 80.5% of the primary Diclofenac pollutant. According to the low energy consumption of this process (EEC=0.014144 US$/m3) and other results, the combination of the PES/CTAC membrane and Ti/SnO2-α-Fe2O3 electrode is an efficient method for diclofenac sodium pollutant removal.

Introduction: Metallic artifacts induced by pacemakers and implantable cardioverter defibrillator (ICD) leads are a limitation of CT-based attenuation correction (CTAC) of PET data in cardiac PET/CT imaging. In this study, the impact of metal artefact reduction (MAR) for CTAC of cardiac PET/CT images in the presence of pacemakers and ICD leads was investigated through both qualitative and quantitative analysis using phantom and clinical studies.Methods: The study included seven patients (three with pacemaker leads and four with ICD leads) undergoing viability examinations using dedicated cardiac PET/CT protocols. For detailed analysis, CT and PET emission data were also obtained using an anthropomorphic thorax phantom and dedicated in-house made heart phantom incorporating pacemaker and ICD leads attached at the right ventricle of the heart. The PET data for both patient and phantom studies were corrected for attenuation using both artefactual CT as well as CT images enhanced using a MAR algorithm. The severity and magnitude of metallic artefacts arising from these leads were assessed on both mmaps and attenuation corrected PET images. VOI-based analysis and regression plots were performed for regions related to leads’ location. Bull’s eye view analysis was also performed on PET images corrected for attenuation with and without the MAR algorithm.Results: In phantom studies, the mean percent difference between tracer uptake obtained without and with MAR were seen to be as much as 10.16±2.1 and 6.86±2.1 in the segments of the heart in the vicinity to the metallic object, whereas they were 4.43±0.5 and 2.98±0.5 in segments far from the metal, for ICD and pacemaker leads, respectively. In clinical studies, the visual assessment of PET images by experienced physicians and quantitative analysis did not report significant differences when PET images are corrected for attenuation with and without MAR.Conclusion: It was concluded that although the MAR algorithm can effectively improve the quality ofμmaps, its clinical impact on the interpretation of PET images is not significant. Therefore cardiac PET images corrected for attenuation using CTAC in the presence of metallic leads can be interpreted without correction for metal artefacts. It should however be emphasized that in some special cases with multiple ICD leads attached to the myocardium wall, MAR might be useful for accurate attenuation correction.

Myocardial perfusion imaging is a non-invasive procedure that plays an integral role in the diagnosis and management of coronary artery disease. With the routine use of computerised tomography attenuation correction (CTAC) in myocardial perfusion imaging still under debate, the aim of this review was to determine the impact of CTAC on image quality in myocardial perfusion imaging. Medline, Embase and CINAHL were searched from the earliest available time until August 2019. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies version 2. Details pertaining to image quality and diagnostic accuracy were analysed, and results summarised descriptively. Three studies with ‘ unclear’ risk of bias and low applicability concerns (1002 participants) from a yield of 2725 articles were identified. Two studies demonstrated an increase in image quality, and one study found no difference in image quality when using CTAC compared to no attenuation correction. Benefits of CTAC for improving image quality remain unclear. Given the potential exposure risk with the addition of CTAC, patient and clinician factors should inform decision making for use of CTAC in myocardial perfusion imaging for coronary artery disease.

Objective(s): The aim of this study was to evaluate the influences of reconstruction and attenuation correction on the differences in the radioactivity distributions in 123I brain SPECT obtained by the hybrid SPECT/CT device.Methods: We used the 3-dimensional (3D) brain phantom, which imitates the precise structure of gray matter, white matter and bone regions. It was filled with 123I solution (20.1 kBq/mL) in the gray matter region and with K2HPO4 in the bone region. The SPECT/CT data were acquired by the hybrid SPECT/CT device. SPECT images were reconstructed by using filtered back projection with uniform attenuation correction (FBP-uAC), 3D ordered-subsets expectation-maximization with uniform AC (3DOSEM- uAC) and 3D OSEM with CT-based non-uniform AC (3D-OSEMCTAC). We evaluated the differences in the radioactivity distributions among these reconstruction methods using a 3D digital phantom, which was developed from CT images of the 3D brain phantom, as a reference. The normalized mean square error (NMSE) and regional radioactivity were calculated to evaluate the similarity of SPECT images to the 3D digital phantom.Results: The NMSE values were 0.0811 in FBP-uAC, 0.0914 in 3D-OSEMuAC and 0.0766 in 3D-OSEM-CTAC. The regional radioactivity of FBP-uAC was 11.5% lower in the middle cerebral artery territory, and that of 3DOSEM- uAC was 5.8% higher in the anterior cerebral artery territory, compared with the digital phantom. On the other hand, that of 3D-OSEMCTAC was 1.8% lower in all brain areas.Conclusion: By using the hybrid SPECT/CT device, the brain SPECT reconstructed by 3D-OSEM with CT attenuation correction can provide an accurate assessment of the distribution of brain radioactivity.

Due to the development of various industries, surfactants are used in detergents and disinfectants, oil industries, soil washing, petrochemicals, etc., and enter the ground in different ways. Surfactants, after entering the soil composition, change the physical and mechanical properties of soils due to physical and chemical processes. In this study, the pollutant effect of anionic, cationic, and non-ionic surfactants on some properties of sandy and sand with 20% clay soil is investigated. For this purpose, compaction, direct shear, consolidation, and capillary tests were performed on the soil exposed to water with 1% of various surfactants. The results showed that surfactants have a negligible effect on the maximum dry unit weight of the granular soil. Also, Triton and HEC surfactants do not have a significant effect on the optimum moisture content, but other surfactants reduced it compared to water. In general, soil shear resistance decreases in the presence of surfactant solutions compared to clean water. Also, according to the results of consolidation tests performed on the sandy soil with 20% clay, HEC, LABSA, and CTAC surfactants increased the compression coefficient and increased the swelling coefficient compared to clean water. HEC surfactants caused a decrease and CTAC and LABSA surfactants increase the consolidation coefficient (CV) compared to water. Also, all surfactants reduced differently the capillary ascend in the soil.

This article presents a method for the electrochemical preparation of a coating of nickel– silica nanocomposites on a carbon steel substrate. The incorporation of hydrophilic silica particles into the Ni composite coating during co-electrodeposition is so difficult due to the small size and the hydrophilicity of SiO2 particle, generally less than 2 v% of silica is incorporated into the composite at different current densities, agitation speeds and silica concentrations. The effect of the presence of four surfactants, namely cocamidopropyl betaine (CAPB), decylglycoside (DG), cetyltrimethyl ammonium chloride (CTAC) and ammonium lauryl ether sulfate (ALES), on overcoming this problem was investigated in this research, and the surfactants were found to greatly influence the surface charge of silica, silica incorporation percentage and the microstructure of the composite. In fact, upon increasing the internal stresses, the products prepared in the presence of CAPB and DG were found to crack to some degree. CTAC was found to lead to entrapment mode silica co-deposition in the Ni coating. Furthermore, the addition of ALES into an electrolyte bath negatively supercharged silica surfaces and increased silica dispersion, which led to a dramatic increase in the silica incorporation percentages to around 14 v%. The results showed that Ni– SiO2 composites prepared in the presence of ALES had better corrosion resistance, hardness and wear properties.

The advent of dual-modality PET/CT imaging has revolutionized the practice of clinical oncology, cardiology and neurology by improving lesions localization and the possibility of accurate quantitative analysis. In addition, the use of CT images for CT-based attenuation correction (CTAC) allows to decrease the overall scanning time and to create a noise-free attenuation map (mmap). The near simultaneous data acquisition in a fixed combination of a PET and a CT scanner in a hybrid PET/CT imaging system with a common patent table minimizes spatial and temporal mismatches between the modalities by elimination the need to move the patient in between exams. As PET/CT technology becomes more widely available, studies are beginning to appear in the literature that document the use of PET/CT in a variety of different cancers, including lung, thyroid, ovarian, lymphoma, and unknown primary cancers, and for general oncology, cardiology and neurology applications. Specific applications of PET/CT, such as those for radiation therapy planning, are also being explored. The purpose of this review paper is to introduce the principles of PET/CT imaging systems and describe the sources of error and artifact in CT-based attenuation correction algorithm. This paper also focuses on recent developments and future trends in hybrid imaging and their areas of application. It should be noted that due to limited space, the references contained herein are for illustrative purposes and are not inclusive; no implication that those chosen are better than others not mentioned is intended.

Introduction: The advent of dual-modality PET/CT scanners has revolutionized clinical oncology by improving lesion localization and facilitating treatment planning for radiotherapy. In addition, the use of CT images for CT-based attenuation correction (CTAC) decreases the overall scanning time and creates a noise-free attenuation map (mmap). CTAC methods include scaling, segmentation, hybrid scaling/segmentation, bilinear and dual energy methods. All CTAC methods require the transformation of CT Hounsfield units (HU) to linear attenuation coefficients (LAC) at 511 keV. The aim of this study is to compare the results of implementing different methods of energy mapping in PET/CT scanners.Materials and Methods: This study was conducted in 2 phases, the first phase in a phantom and the second one on patient data. To perform the first phase, a cylindrical phantom with different concentrations of K2HPO4 inserts was CT scanned and energy mapping methods were implemented on it. For performing the second phase, different energy mapping methods were implemented on several clinical studies and compared to the transmission (TX) image derived using Ga-68 radionuclide source acquired on the GE Discovery LS PET/CT scanner.Results: An ROI analysis was performed on different positions of the resultant µmaps and the average mvalue of each ROI was compared to the reference value. The results of the µmaps obtained for 511 keV compared to the theoretical values showed that in the phantom for low concentrations of K2HPO4 all these methods produce 511 keV attenuation maps with small relative difference compared to gold standard. The relative difference for scaling, segmentation, hybrid, bilinear and dual energy methods was 4.92, 3.21, 4.43, 2.24 and 2.29%, respectively. Although for high concentration of K2HPO4 the three methods; hybrid scaling/segmentation, bilinear and dual energy produced the lowest relative difference of 10.91, 10.88 and 5%, respectively. For patients it was found that for soft tissues all the mentioned energy mapping methods produce acceptable attenuation map at 511 keV. The relative difference of scaling, segmentation, hybrid, and bilinear methods compared to TX method was 6.95, 4.51, 7, and 6.45% respectively. For bony tissues, the quantitative analysis showed that scaling and segmentation method produce high relative difference of 26 and 23.2%, respectively and the relative difference of hybrid and bilinear in comparison to TX method was 10.7 and 20%, respectively.Discussion and Conclusion: Based on the result obtained from these two studies it can be concluded that for soft tissues all energy mapping methods yield acceptable results while for bony tissues all the mentioned methods except the scaling and segmentation yield acceptable results.

Background: 99m-Tc Ethyl-Cysteinate-Dimer SPECT and MR imaging play a significant role in diagnosing anosmia. In this study, two-tissue class and three-tissue class attenuation maps (2C-MR and 3C-MR) obtained from MR images were compared with CT-based attenuation correction (CTAC). Afterward, the presence of hypo-perfusion in brain lobes was evaluated in SPECT images. Materials and Methods: The 2C-MRAC map was generated through segmentation of T1-W MR images into air and soft-tissue, while in the 3C-MRAC map, the cortical bone was also considered. For investigating MRAC approaches, the difference between activity concentration (ACC) values was estimated in 144 volumes of interest. Ten normal and fourteen anosmic patients were compared by calculating the average normalized count and standard uptake value ratio parameters in the brain lobes. Results: The comparison between attenuation correction strategies represented that MRAC images resulted in underestimation of the ACC values which was more substantial in the cortical area rather than in central regions (maximum 9% vs. 6% for 2C-MR and maximum 5. 5% vs. 3. 5% for 3C-MR). Nevertheless, there was a strong correlation between the MRAC and CTAC methods with a correlation coefficient of 0. 7 for both 2C-MR and 3C-MR. The statistical analysis between normal and affected groups indicated the hypo-perfusion in the cortex of Lh_frontal, Rh and Lh_temporal lobes with p-values < 0. 05. Conclusions: Using MRAC resulted in underestimation of activity concentration which was partly eliminated by considering the cortical bone in the 3C-MR attenuation map. Hypo-perfusion was perceived in Frontal and Temporal lobes in SPECT-MRAC images of the anosmic group.